ext: Upgrade PyBind11 to version 2.2.1

This upgrade is necessary for pybind to build with GCC 7.2.

We still need to add the patch for stl.h. MSC_FULL_VER change is no longer
needed.
See https://gem5-review.googlesource.com/c/public/gem5/+/2230

Change-Id: I806729217d022070583994c2dfcaa74476aef30f
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/5801
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

95 files changed, 8613 insertions, 4796 deletions

diff --git a/ext/pybind11/tests/CMakeLists.txt b/ext/pybind11/tests/CMakeLists.txt
index 11be49e53..25e06662c 100644
--- a/ext/pybind11/tests/CMakeLists.txt
+++ b/ext/pybind11/tests/CMakeLists.txt
@@ -12,7 +12,7 @@ option(PYBIND11_WERROR  "Report all warnings as errors"  OFF)
 if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
     # We're being loaded directly, i.e. not via add_subdirectory, so make this
     # work as its own project and load the pybind11Config to get the tools we need
-    project(pybind11_tests)
+    project(pybind11_tests CXX)
 
     find_package(pybind11 REQUIRED CONFIG)
 endif()
@@ -26,22 +26,23 @@ endif()
 
 # Full set of test files (you can override these; see below)
 set(PYBIND11_TEST_FILES
-  test_alias_initialization.cpp
   test_buffers.cpp
+  test_builtin_casters.cpp
+  test_call_policies.cpp
   test_callbacks.cpp
   test_chrono.cpp
-  test_class_args.cpp
+  test_class.cpp
   test_constants_and_functions.cpp
-  test_copy_move_policies.cpp
+  test_copy_move.cpp
   test_docstring_options.cpp
   test_eigen.cpp
   test_enum.cpp
   test_eval.cpp
   test_exceptions.cpp
-  test_inheritance.cpp
-  test_issues.cpp
-  test_keep_alive.cpp
+  test_factory_constructors.cpp
+  test_iostream.cpp
   test_kwargs_and_defaults.cpp
+  test_local_bindings.cpp
   test_methods_and_attributes.cpp
   test_modules.cpp
   test_multiple_inheritance.cpp
@@ -51,15 +52,16 @@ set(PYBIND11_TEST_FILES
   test_opaque_types.cpp
   test_operator_overloading.cpp
   test_pickling.cpp
-  test_python_types.cpp
+  test_pytypes.cpp
   test_sequences_and_iterators.cpp
   test_smart_ptr.cpp
+  test_stl.cpp
   test_stl_binders.cpp
   test_virtual_functions.cpp
 )
 
 # Invoking cmake with something like:
-#     cmake -DPYBIND11_TEST_OVERRIDE="test_issues.cpp;test_picking.cpp" ..
+#     cmake -DPYBIND11_TEST_OVERRIDE="test_callbacks.cpp;test_picking.cpp" ..
 # lets you override the tests that get compiled and run.  You can restore to all tests with:
 #     cmake -DPYBIND11_TEST_OVERRIDE= ..
 if (PYBIND11_TEST_OVERRIDE)
@@ -68,6 +70,16 @@ endif()
 
 string(REPLACE ".cpp" ".py" PYBIND11_PYTEST_FILES "${PYBIND11_TEST_FILES}")
 
+# Contains the set of test files that require pybind11_cross_module_tests to be
+# built; if none of these are built (i.e. because TEST_OVERRIDE is used and
+# doesn't include them) the second module doesn't get built.
+set(PYBIND11_CROSS_MODULE_TESTS
+  test_exceptions.py
+  test_local_bindings.py
+  test_stl.py
+  test_stl_binders.py
+)
+
 # Check if Eigen is available; if not, remove from PYBIND11_TEST_FILES (but
 # keep it in PYBIND11_PYTEST_FILES, so that we get the "eigen is not installed"
 # skip message).
@@ -104,6 +116,9 @@ if(PYBIND11_TEST_FILES_EIGEN_I GREATER -1)
   endif()
 endif()
 
+# Optional dependency for some tests (boost::variant is only supported with version >= 1.56)
+find_package(Boost 1.56)
+
 # Compile with compiler warnings turned on
 function(pybind11_enable_warnings target_name)
   if(MSVC)
@@ -121,32 +136,55 @@ function(pybind11_enable_warnings target_name)
   endif()
 endfunction()
 
+set(test_targets pybind11_tests)
+
+# Build pybind11_cross_module_tests if any test_whatever.py are being built that require it
+foreach(t ${PYBIND11_CROSS_MODULE_TESTS})
+  list(FIND PYBIND11_PYTEST_FILES ${t} i)
+  if (i GREATER -1)
+    list(APPEND test_targets pybind11_cross_module_tests)
+    break()
+  endif()
+endforeach()
 
-# Create the binding library
-pybind11_add_module(pybind11_tests THIN_LTO pybind11_tests.cpp
-  ${PYBIND11_TEST_FILES} ${PYBIND11_HEADERS})
+set(testdir ${CMAKE_CURRENT_SOURCE_DIR})
+foreach(target ${test_targets})
+  set(test_files ${PYBIND11_TEST_FILES})
+  if(NOT target STREQUAL "pybind11_tests")
+    set(test_files "")
+  endif()
 
-pybind11_enable_warnings(pybind11_tests)
+  # Create the binding library
+  pybind11_add_module(${target} THIN_LTO ${target}.cpp ${test_files} ${PYBIND11_HEADERS})
+  pybind11_enable_warnings(${target})
 
-if(EIGEN3_FOUND)
-  if (PYBIND11_EIGEN_VIA_TARGET)
-    target_link_libraries(pybind11_tests PRIVATE Eigen3::Eigen)
-  else()
-    target_include_directories(pybind11_tests PRIVATE ${EIGEN3_INCLUDE_DIR})
+  if(MSVC)
+    target_compile_options(${target} PRIVATE /utf-8)
   endif()
-  target_compile_definitions(pybind11_tests PRIVATE -DPYBIND11_TEST_EIGEN)
-endif()
 
-set(testdir ${CMAKE_CURRENT_SOURCE_DIR})
+  if(EIGEN3_FOUND)
+    if (PYBIND11_EIGEN_VIA_TARGET)
+      target_link_libraries(${target} PRIVATE Eigen3::Eigen)
+    else()
+      target_include_directories(${target} PRIVATE ${EIGEN3_INCLUDE_DIR})
+    endif()
+    target_compile_definitions(${target} PRIVATE -DPYBIND11_TEST_EIGEN)
+  endif()
 
-# Always write the output file directly into the 'tests' directory (even on MSVC)
-if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
-  set_target_properties(pybind11_tests PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${testdir})
-  foreach(config ${CMAKE_CONFIGURATION_TYPES})
-    string(TOUPPER ${config} config)
-    set_target_properties(pybind11_tests PROPERTIES LIBRARY_OUTPUT_DIRECTORY_${config} ${testdir})
-  endforeach()
-endif()
+  if(Boost_FOUND)
+    target_include_directories(${target} PRIVATE ${Boost_INCLUDE_DIRS})
+    target_compile_definitions(${target} PRIVATE -DPYBIND11_TEST_BOOST)
+  endif()
+
+  # Always write the output file directly into the 'tests' directory (even on MSVC)
+  if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+    set_target_properties(${target} PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${testdir})
+    foreach(config ${CMAKE_CONFIGURATION_TYPES})
+      string(TOUPPER ${config} config)
+      set_target_properties(${target} PROPERTIES LIBRARY_OUTPUT_DIRECTORY_${config} ${testdir})
+    endforeach()
+  endif()
+endforeach()
 
 # Make sure pytest is found or produce a fatal error
 if(NOT PYBIND11_PYTEST_FOUND)
@@ -162,9 +200,15 @@ if(NOT PYBIND11_PYTEST_FOUND)
   set(PYBIND11_PYTEST_FOUND TRUE CACHE INTERNAL "")
 endif()
 
+if(CMAKE_VERSION VERSION_LESS 3.2)
+  set(PYBIND11_USES_TERMINAL "")
+else()
+  set(PYBIND11_USES_TERMINAL "USES_TERMINAL")
+endif()
+
 # A single command to compile and run the tests
 add_custom_target(pytest COMMAND ${PYTHON_EXECUTABLE} -m pytest ${PYBIND11_PYTEST_FILES}
-                  DEPENDS pybind11_tests WORKING_DIRECTORY ${testdir})
+                  DEPENDS ${test_targets} WORKING_DIRECTORY ${testdir} ${PYBIND11_USES_TERMINAL})
 
 if(PYBIND11_TEST_OVERRIDE)
   add_custom_command(TARGET pytest POST_BUILD
@@ -180,59 +224,13 @@ if (NOT PROJECT_NAME STREQUAL "pybind11")
   return()
 endif()
 
-# Add a post-build comment to show the .so size and, if a previous size, compare it:
+# Add a post-build comment to show the primary test suite .so size and, if a previous size, compare it:
 add_custom_command(TARGET pybind11_tests POST_BUILD
   COMMAND ${PYTHON_EXECUTABLE} ${PROJECT_SOURCE_DIR}/tools/libsize.py
   $<TARGET_FILE:pybind11_tests> ${CMAKE_CURRENT_BINARY_DIR}/sosize-$<TARGET_FILE_NAME:pybind11_tests>.txt)
 
-# Test CMake build using functions and targets from subdirectory or installed location
-add_custom_target(test_cmake_build)
-if(NOT CMAKE_VERSION VERSION_LESS 3.1)
-  # 3.0 needed for interface library for subdirectory_target/installed_target
-  # 3.1 needed for cmake -E env for testing
-
-  include(CMakeParseArguments)
-  function(pybind11_add_build_test name)
-    cmake_parse_arguments(ARG "INSTALL" "" "" ${ARGN})
-
-    set(build_options "-DCMAKE_PREFIX_PATH=${PROJECT_BINARY_DIR}/mock_install"
-                      "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
-                      "-DPYTHON_EXECUTABLE=${PYTHON_EXECUTABLE}"
-                      "-DPYBIND11_CPP_STANDARD=${PYBIND11_CPP_STANDARD}")
-    if(NOT ARG_INSTALL)
-      list(APPEND build_options "-DPYBIND11_PROJECT_DIR=${PROJECT_SOURCE_DIR}")
-    endif()
+# Test embedding the interpreter. Provides the `cpptest` target.
+add_subdirectory(test_embed)
 
-    add_custom_target(test_${name} ${CMAKE_CTEST_COMMAND}
-      --quiet --output-log test_cmake_build/${name}.log
-      --build-and-test "${CMAKE_CURRENT_SOURCE_DIR}/test_cmake_build/${name}"
-                       "${CMAKE_CURRENT_BINARY_DIR}/test_cmake_build/${name}"
-      --build-config Release
-      --build-noclean
-      --build-generator ${CMAKE_GENERATOR}
-      $<$<BOOL:${CMAKE_GENERATOR_PLATFORM}>:--build-generator-platform> ${CMAKE_GENERATOR_PLATFORM}
-      --build-makeprogram ${CMAKE_MAKE_PROGRAM}
-      --build-target check
-      --build-options ${build_options}
-    )
-    if(ARG_INSTALL)
-      add_dependencies(test_${name} mock_install)
-    endif()
-    add_dependencies(test_cmake_build test_${name})
-  endfunction()
-
-  pybind11_add_build_test(subdirectory_function)
-  pybind11_add_build_test(subdirectory_target)
-
-  if(PYBIND11_INSTALL)
-    add_custom_target(mock_install ${CMAKE_COMMAND}
-      "-DCMAKE_INSTALL_PREFIX=${PROJECT_BINARY_DIR}/mock_install"
-      -P "${PROJECT_BINARY_DIR}/cmake_install.cmake"
-    )
-
-    pybind11_add_build_test(installed_function INSTALL)
-    pybind11_add_build_test(installed_target INSTALL)
-  endif()
-endif()
-
-add_dependencies(check test_cmake_build)
+# Test CMake build using functions and targets from subdirectory or installed location
+add_subdirectory(test_cmake_build)
diff --git a/ext/pybind11/tests/conftest.py b/ext/pybind11/tests/conftest.py
index 5b08004e3..f4c228260 100644
--- a/ext/pybind11/tests/conftest.py
+++ b/ext/pybind11/tests/conftest.py
@@ -196,7 +196,7 @@ def pytest_namespace():
     except ImportError:
         scipy = None
     try:
-        from pybind11_tests import have_eigen
+        from pybind11_tests.eigen import have_eigen
     except ImportError:
         have_eigen = False
     pypy = platform.python_implementation() == "PyPy"
@@ -211,6 +211,8 @@ def pytest_namespace():
         'requires_eigen_and_scipy': skipif(not have_eigen or not scipy,
                                            reason="eigen and/or scipy are not installed"),
         'unsupported_on_pypy': skipif(pypy, reason="unsupported on PyPy"),
+        'unsupported_on_py2': skipif(sys.version_info.major < 3,
+                                     reason="unsupported on Python 2.x"),
         'gc_collect': gc_collect
     }
 
diff --git a/ext/pybind11/tests/constructor_stats.h b/ext/pybind11/tests/constructor_stats.h
index f66ff71df..babded032 100644
--- a/ext/pybind11/tests/constructor_stats.h
+++ b/ext/pybind11/tests/constructor_stats.h
@@ -169,7 +169,7 @@ public:
         auto &internals = py::detail::get_internals();
         const std::type_index *t1 = nullptr, *t2 = nullptr;
         try {
-            auto *type_info = internals.registered_types_py.at(class_.ptr());
+            auto *type_info = internals.registered_types_py.at((PyTypeObject *) class_.ptr()).at(0);
             for (auto &p : internals.registered_types_cpp) {
                 if (p.second == type_info) {
                     if (t1) {
diff --git a/ext/pybind11/tests/local_bindings.h b/ext/pybind11/tests/local_bindings.h
new file mode 100644
index 000000000..b6afb8086
--- /dev/null
+++ b/ext/pybind11/tests/local_bindings.h
@@ -0,0 +1,64 @@
+#pragma once
+#include "pybind11_tests.h"
+
+/// Simple class used to test py::local:
+template <int> class LocalBase {
+public:
+    LocalBase(int i) : i(i) { }
+    int i = -1;
+};
+
+/// Registered with py::module_local in both main and secondary modules:
+using LocalType = LocalBase<0>;
+/// Registered without py::module_local in both modules:
+using NonLocalType = LocalBase<1>;
+/// A second non-local type (for stl_bind tests):
+using NonLocal2 = LocalBase<2>;
+/// Tests within-module, different-compilation-unit local definition conflict:
+using LocalExternal = LocalBase<3>;
+/// Mixed: registered local first, then global
+using MixedLocalGlobal = LocalBase<4>;
+/// Mixed: global first, then local
+using MixedGlobalLocal = LocalBase<5>;
+
+/// Registered with py::module_local only in the secondary module:
+using ExternalType1 = LocalBase<6>;
+using ExternalType2 = LocalBase<7>;
+
+using LocalVec = std::vector<LocalType>;
+using LocalVec2 = std::vector<NonLocal2>;
+using LocalMap = std::unordered_map<std::string, LocalType>;
+using NonLocalVec = std::vector<NonLocalType>;
+using NonLocalVec2 = std::vector<NonLocal2>;
+using NonLocalMap = std::unordered_map<std::string, NonLocalType>;
+using NonLocalMap2 = std::unordered_map<std::string, uint8_t>;
+
+PYBIND11_MAKE_OPAQUE(LocalVec);
+PYBIND11_MAKE_OPAQUE(LocalVec2);
+PYBIND11_MAKE_OPAQUE(LocalMap);
+PYBIND11_MAKE_OPAQUE(NonLocalVec);
+//PYBIND11_MAKE_OPAQUE(NonLocalVec2); // same type as LocalVec2
+PYBIND11_MAKE_OPAQUE(NonLocalMap);
+PYBIND11_MAKE_OPAQUE(NonLocalMap2);
+
+
+// Simple bindings (used with the above):
+template <typename T, int Adjust = 0, typename... Args>
+py::class_<T> bind_local(Args && ...args) {
+    return py::class_<T>(std::forward<Args>(args)...)
+        .def(py::init<int>())
+        .def("get", [](T &i) { return i.i + Adjust; });
+};
+
+// Simulate a foreign library base class (to match the example in the docs):
+namespace pets {
+class Pet {
+public:
+    Pet(std::string name) : name_(name) {}
+    std::string name_;
+    const std::string &name() { return name_; }
+};
+}
+
+struct MixGL { int i; MixGL(int i) : i{i} {} };
+struct MixGL2 { int i; MixGL2(int i) : i{i} {} };
diff --git a/ext/pybind11/tests/pybind11_cross_module_tests.cpp b/ext/pybind11/tests/pybind11_cross_module_tests.cpp
new file mode 100644
index 000000000..f705e3106
--- /dev/null
+++ b/ext/pybind11/tests/pybind11_cross_module_tests.cpp
@@ -0,0 +1,123 @@
+/*
+    tests/pybind11_cross_module_tests.cpp -- contains tests that require multiple modules
+
+    Copyright (c) 2017 Jason Rhinelander <jason@imaginary.ca>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include "local_bindings.h"
+#include <pybind11/stl_bind.h>
+#include <numeric>
+
+PYBIND11_MODULE(pybind11_cross_module_tests, m) {
+    m.doc() = "pybind11 cross-module test module";
+
+    // test_local_bindings.py tests:
+    //
+    // Definitions here are tested by importing both this module and the
+    // relevant pybind11_tests submodule from a test_whatever.py
+
+    // test_load_external
+    bind_local<ExternalType1>(m, "ExternalType1", py::module_local());
+    bind_local<ExternalType2>(m, "ExternalType2", py::module_local());
+
+    // test_exceptions.py
+    m.def("raise_runtime_error", []() { PyErr_SetString(PyExc_RuntimeError, "My runtime error"); throw py::error_already_set(); });
+    m.def("raise_value_error", []() { PyErr_SetString(PyExc_ValueError, "My value error"); throw py::error_already_set(); });
+    m.def("throw_pybind_value_error", []() { throw py::value_error("pybind11 value error"); });
+    m.def("throw_pybind_type_error", []() { throw py::type_error("pybind11 type error"); });
+    m.def("throw_stop_iteration", []() { throw py::stop_iteration(); });
+
+    // test_local_bindings.py
+    // Local to both:
+    bind_local<LocalType, 1>(m, "LocalType", py::module_local())
+        .def("get2", [](LocalType &t) { return t.i + 2; })
+        ;
+
+    // Can only be called with our python type:
+    m.def("local_value", [](LocalType &l) { return l.i; });
+
+    // test_nonlocal_failure
+    // This registration will fail (global registration when LocalFail is already registered
+    // globally in the main test module):
+    m.def("register_nonlocal", [m]() {
+        bind_local<NonLocalType, 0>(m, "NonLocalType");
+    });
+
+    // test_stl_bind_local
+    // stl_bind.h binders defaults to py::module_local if the types are local or converting:
+    py::bind_vector<LocalVec>(m, "LocalVec");
+    py::bind_map<LocalMap>(m, "LocalMap");
+
+    // test_stl_bind_global
+    // and global if the type (or one of the types, for the map) is global (so these will fail,
+    // assuming pybind11_tests is already loaded):
+    m.def("register_nonlocal_vec", [m]() {
+        py::bind_vector<NonLocalVec>(m, "NonLocalVec");
+    });
+    m.def("register_nonlocal_map", [m]() {
+        py::bind_map<NonLocalMap>(m, "NonLocalMap");
+    });
+    // The default can, however, be overridden to global using `py::module_local()` or
+    // `py::module_local(false)`.
+    // Explicitly made local:
+    py::bind_vector<NonLocalVec2>(m, "NonLocalVec2", py::module_local());
+    // Explicitly made global (and so will fail to bind):
+    m.def("register_nonlocal_map2", [m]() {
+        py::bind_map<NonLocalMap2>(m, "NonLocalMap2", py::module_local(false));
+    });
+
+    // test_mixed_local_global
+    // We try this both with the global type registered first and vice versa (the order shouldn't
+    // matter).
+    m.def("register_mixed_global_local", [m]() {
+        bind_local<MixedGlobalLocal, 200>(m, "MixedGlobalLocal", py::module_local());
+    });
+    m.def("register_mixed_local_global", [m]() {
+        bind_local<MixedLocalGlobal, 2000>(m, "MixedLocalGlobal", py::module_local(false));
+    });
+    m.def("get_mixed_gl", [](int i) { return MixedGlobalLocal(i); });
+    m.def("get_mixed_lg", [](int i) { return MixedLocalGlobal(i); });
+
+    // test_internal_locals_differ
+    m.def("local_cpp_types_addr", []() { return (uintptr_t) &py::detail::registered_local_types_cpp(); });
+
+    // test_stl_caster_vs_stl_bind
+    py::bind_vector<std::vector<int>>(m, "VectorInt");
+
+    m.def("load_vector_via_binding", [](std::vector<int> &v) {
+        return std::accumulate(v.begin(), v.end(), 0);
+    });
+
+    // test_cross_module_calls
+    m.def("return_self", [](LocalVec *v) { return v; });
+    m.def("return_copy", [](const LocalVec &v) { return LocalVec(v); });
+
+    class Dog : public pets::Pet { public: Dog(std::string name) : Pet(name) {}; };
+    py::class_<pets::Pet>(m, "Pet", py::module_local())
+        .def("name", &pets::Pet::name);
+    // Binding for local extending class:
+    py::class_<Dog, pets::Pet>(m, "Dog")
+        .def(py::init<std::string>());
+    m.def("pet_name", [](pets::Pet &p) { return p.name(); });
+
+    py::class_<MixGL>(m, "MixGL", py::module_local()).def(py::init<int>());
+    m.def("get_gl_value", [](MixGL &o) { return o.i + 100; });
+
+    py::class_<MixGL2>(m, "MixGL2", py::module_local()).def(py::init<int>());
+
+    // test_vector_bool
+    // We can't test both stl.h and stl_bind.h conversions of `std::vector<bool>` within
+    // the same module (it would be an ODR violation). Therefore `bind_vector` of `bool`
+    // is defined here and tested in `test_stl_binders.py`.
+    py::bind_vector<std::vector<bool>>(m, "VectorBool");
+
+    // test_missing_header_message
+    // The main module already includes stl.h, but we need to test the error message
+    // which appears when this header is missing.
+    m.def("missing_header_arg", [](std::vector<float>) { });
+    m.def("missing_header_return", []() { return std::vector<float>(); });
+}
diff --git a/ext/pybind11/tests/pybind11_tests.cpp b/ext/pybind11/tests/pybind11_tests.cpp
index 1d805d75b..bc7d2c3e7 100644
--- a/ext/pybind11/tests/pybind11_tests.cpp
+++ b/ext/pybind11/tests/pybind11_tests.cpp
@@ -10,6 +10,9 @@
 #include "pybind11_tests.h"
 #include "constructor_stats.h"
 
+#include <functional>
+#include <list>
+
 /*
 For testing purposes, we define a static global variable here in a function that each individual
 test .cpp calls with its initialization lambda.  It's convenient here because we can just not
@@ -28,8 +31,15 @@ std::list<std::function<void(py::module &)>> &initializers() {
     return inits;
 }
 
-test_initializer::test_initializer(std::function<void(py::module &)> initializer) {
-    initializers().push_back(std::move(initializer));
+test_initializer::test_initializer(Initializer init) {
+    initializers().push_back(init);
+}
+
+test_initializer::test_initializer(const char *submodule_name, Initializer init) {
+    initializers().push_back([=](py::module &parent) {
+        auto m = parent.def_submodule(submodule_name);
+        init(m);
+    });
 }
 
 void bind_ConstructorStats(py::module &m) {
@@ -41,18 +51,43 @@ void bind_ConstructorStats(py::module &m) {
         .def_readwrite("move_assignments", &ConstructorStats::move_assignments)
         .def_readwrite("copy_constructions", &ConstructorStats::copy_constructions)
         .def_readwrite("move_constructions", &ConstructorStats::move_constructions)
-        .def_static("get", (ConstructorStats &(*)(py::object)) &ConstructorStats::get, py::return_value_policy::reference_internal);
+        .def_static("get", (ConstructorStats &(*)(py::object)) &ConstructorStats::get, py::return_value_policy::reference_internal)
+
+        // Not exactly ConstructorStats, but related: expose the internal pybind number of registered instances
+        // to allow instance cleanup checks (invokes a GC first)
+        .def_static("detail_reg_inst", []() {
+            ConstructorStats::gc();
+            return py::detail::get_internals().registered_instances.size();
+        })
+        ;
 }
 
-PYBIND11_PLUGIN(pybind11_tests) {
-    py::module m("pybind11_tests", "pybind testing plugin");
+PYBIND11_MODULE(pybind11_tests, m) {
+    m.doc() = "pybind11 test module";
 
     bind_ConstructorStats(m);
 
+#if !defined(NDEBUG)
+    m.attr("debug_enabled") = true;
+#else
+    m.attr("debug_enabled") = false;
+#endif
+
+    py::class_<UserType>(m, "UserType", "A `py::class_` type for testing")
+        .def(py::init<>())
+        .def(py::init<int>())
+        .def("get_value", &UserType::value, "Get value using a method")
+        .def("set_value", &UserType::set, "Set value using a method")
+        .def_property("value", &UserType::value, &UserType::set, "Get/set value using a property")
+        .def("__repr__", [](const UserType& u) { return "UserType({})"_s.format(u.value()); });
+
+    py::class_<IncType, UserType>(m, "IncType")
+        .def(py::init<>())
+        .def(py::init<int>())
+        .def("__repr__", [](const IncType& u) { return "IncType({})"_s.format(u.value()); });
+
     for (const auto &initializer : initializers())
         initializer(m);
 
     if (!py::hasattr(m, "have_eigen")) m.attr("have_eigen") = false;
-
-    return m.ptr();
 }
diff --git a/ext/pybind11/tests/pybind11_tests.h b/ext/pybind11/tests/pybind11_tests.h
index c11b687b2..90963a5de 100644
--- a/ext/pybind11/tests/pybind11_tests.h
+++ b/ext/pybind11/tests/pybind11_tests.h
@@ -1,12 +1,65 @@
 #pragma once
 #include <pybind11/pybind11.h>
-#include <functional>
-#include <list>
+
+#if defined(_MSC_VER) && _MSC_VER < 1910
+// We get some really long type names here which causes MSVC 2015 to emit warnings
+#  pragma warning(disable: 4503) // warning C4503: decorated name length exceeded, name was truncated
+#endif
 
 namespace py = pybind11;
 using namespace pybind11::literals;
 
 class test_initializer {
+    using Initializer = void (*)(py::module &);
+
+public:
+    test_initializer(Initializer init);
+    test_initializer(const char *submodule_name, Initializer init);
+};
+
+#define TEST_SUBMODULE(name, variable)                   \
+    void test_submodule_##name(py::module &);            \
+    test_initializer name(#name, test_submodule_##name); \
+    void test_submodule_##name(py::module &variable)
+
+
+/// Dummy type which is not exported anywhere -- something to trigger a conversion error
+struct UnregisteredType { };
+
+/// A user-defined type which is exported and can be used by any test
+class UserType {
+public:
+    UserType() = default;
+    UserType(int i) : i(i) { }
+
+    int value() const { return i; }
+    void set(int set) { i = set; }
+
+private:
+    int i = -1;
+};
+
+/// Like UserType, but increments `value` on copy for quick reference vs. copy tests
+class IncType : public UserType {
+public:
+    using UserType::UserType;
+    IncType() = default;
+    IncType(const IncType &other) : IncType(other.value() + 1) { }
+    IncType(IncType &&) = delete;
+    IncType &operator=(const IncType &) = delete;
+    IncType &operator=(IncType &&) = delete;
+};
+
+/// Custom cast-only type that casts to a string "rvalue" or "lvalue" depending on the cast context.
+/// Used to test recursive casters (e.g. std::tuple, stl containers).
+struct RValueCaster {};
+NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(detail)
+template<> class type_caster<RValueCaster> {
 public:
-    test_initializer(std::function<void(py::module &)> initializer);
+    PYBIND11_TYPE_CASTER(RValueCaster, _("RValueCaster"));
+    static handle cast(RValueCaster &&, return_value_policy, handle) { return py::str("rvalue").release(); }
+    static handle cast(const RValueCaster &, return_value_policy, handle) { return py::str("lvalue").release(); }
 };
+NAMESPACE_END(detail)
+NAMESPACE_END(pybind11)
diff --git a/ext/pybind11/tests/pytest.ini b/ext/pybind11/tests/pytest.ini
index 401cbe0ad..1e44f0a05 100644
--- a/ext/pybind11/tests/pytest.ini
+++ b/ext/pybind11/tests/pytest.ini
@@ -1,7 +1,15 @@
 [pytest]
 minversion = 3.0
+norecursedirs = test_cmake_build test_embed
 addopts =
     # show summary of skipped tests
     -rs
     # capture only Python print and C++ py::print, but not C output (low-level Python errors)
     --capture=sys
+filterwarnings =
+    # make warnings into errors but ignore certain third-party extension issues
+    error
+    # importing scipy submodules on some version of Python
+    ignore::ImportWarning
+    # bogus numpy ABI warning (see numpy/#432)
+    ignore:.*numpy.dtype size changed.*:RuntimeWarning
diff --git a/ext/pybind11/tests/test_alias_initialization.cpp b/ext/pybind11/tests/test_alias_initialization.cpp
deleted file mode 100644
index 48e595695..000000000
--- a/ext/pybind11/tests/test_alias_initialization.cpp
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
-    tests/test_alias_initialization.cpp -- test cases and example of different trampoline
-    initialization modes
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>, Jason Rhinelander <jason@imaginary.ca>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-test_initializer alias_initialization([](py::module &m) {
-    // don't invoke Python dispatch classes by default when instantiating C++ classes that were not
-    // extended on the Python side
-    struct A {
-        virtual ~A() {}
-        virtual void f() { py::print("A.f()"); }
-    };
-
-    struct PyA : A {
-        PyA() { py::print("PyA.PyA()"); }
-        ~PyA() { py::print("PyA.~PyA()"); }
-
-        void f() override {
-            py::print("PyA.f()");
-            PYBIND11_OVERLOAD(void, A, f);
-        }
-    };
-
-    auto call_f = [](A *a) { a->f(); };
-
-    py::class_<A, PyA>(m, "A")
-        .def(py::init<>())
-        .def("f", &A::f);
-
-    m.def("call_f", call_f);
-
-
-    // ... unless we explicitly request it, as in this example:
-    struct A2 {
-        virtual ~A2() {}
-        virtual void f() { py::print("A2.f()"); }
-    };
-
-    struct PyA2 : A2 {
-        PyA2() { py::print("PyA2.PyA2()"); }
-        ~PyA2() { py::print("PyA2.~PyA2()"); }
-        void f() override {
-            py::print("PyA2.f()");
-            PYBIND11_OVERLOAD(void, A2, f);
-        }
-    };
-
-    py::class_<A2, PyA2>(m, "A2")
-        .def(py::init_alias<>())
-        .def("f", &A2::f);
-
-    m.def("call_f", [](A2 *a2) { a2->f(); });
-
-});
-
diff --git a/ext/pybind11/tests/test_alias_initialization.py b/ext/pybind11/tests/test_alias_initialization.py
deleted file mode 100644
index fb90cfc7b..000000000
--- a/ext/pybind11/tests/test_alias_initialization.py
+++ /dev/null
@@ -1,80 +0,0 @@
-import pytest
-
-
-def test_alias_delay_initialization1(capture):
-    """
-    A only initializes its trampoline class when we inherit from it; if we just
-    create and use an A instance directly, the trampoline initialization is
-    bypassed and we only initialize an A() instead (for performance reasons).
-    """
-    from pybind11_tests import A, call_f
-
-    class B(A):
-        def __init__(self):
-            super(B, self).__init__()
-
-        def f(self):
-            print("In python f()")
-
-    # C++ version
-    with capture:
-        a = A()
-        call_f(a)
-        del a
-        pytest.gc_collect()
-    assert capture == "A.f()"
-
-    # Python version
-    with capture:
-        b = B()
-        call_f(b)
-        del b
-        pytest.gc_collect()
-    assert capture == """
-        PyA.PyA()
-        PyA.f()
-        In python f()
-        PyA.~PyA()
-    """
-
-
-def test_alias_delay_initialization2(capture):
-    """A2, unlike the above, is configured to always initialize the alias; while
-    the extra initialization and extra class layer has small virtual dispatch
-    performance penalty, it also allows us to do more things with the trampoline
-    class such as defining local variables and performing construction/destruction.
-    """
-    from pybind11_tests import A2, call_f
-
-    class B2(A2):
-        def __init__(self):
-            super(B2, self).__init__()
-
-        def f(self):
-            print("In python B2.f()")
-
-    # No python subclass version
-    with capture:
-        a2 = A2()
-        call_f(a2)
-        del a2
-        pytest.gc_collect()
-    assert capture == """
-        PyA2.PyA2()
-        PyA2.f()
-        A2.f()
-        PyA2.~PyA2()
-    """
-
-    # Python subclass version
-    with capture:
-        b2 = B2()
-        call_f(b2)
-        del b2
-        pytest.gc_collect()
-    assert capture == """
-        PyA2.PyA2()
-        PyA2.f()
-        In python B2.f()
-        PyA2.~PyA2()
-    """
diff --git a/ext/pybind11/tests/test_buffers.cpp b/ext/pybind11/tests/test_buffers.cpp
index 057250d29..5be717730 100644
--- a/ext/pybind11/tests/test_buffers.cpp
+++ b/ext/pybind11/tests/test_buffers.cpp
@@ -10,93 +10,94 @@
 #include "pybind11_tests.h"
 #include "constructor_stats.h"
 
-class Matrix {
-public:
-    Matrix(size_t rows, size_t cols) : m_rows(rows), m_cols(cols) {
-        print_created(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
-        m_data = new float[rows*cols];
-        memset(m_data, 0, sizeof(float) * rows * cols);
-    }
-
-    Matrix(const Matrix &s) : m_rows(s.m_rows), m_cols(s.m_cols) {
-        print_copy_created(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
-        m_data = new float[m_rows * m_cols];
-        memcpy(m_data, s.m_data, sizeof(float) * m_rows * m_cols);
-    }
-
-    Matrix(Matrix &&s) : m_rows(s.m_rows), m_cols(s.m_cols), m_data(s.m_data) {
-        print_move_created(this);
-        s.m_rows = 0;
-        s.m_cols = 0;
-        s.m_data = nullptr;
-    }
-
-    ~Matrix() {
-        print_destroyed(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
-        delete[] m_data;
-    }
-
-    Matrix &operator=(const Matrix &s) {
-        print_copy_assigned(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
-        delete[] m_data;
-        m_rows = s.m_rows;
-        m_cols = s.m_cols;
-        m_data = new float[m_rows * m_cols];
-        memcpy(m_data, s.m_data, sizeof(float) * m_rows * m_cols);
-        return *this;
-    }
-
-    Matrix &operator=(Matrix &&s) {
-        print_move_assigned(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
-        if (&s != this) {
-            delete[] m_data;
-            m_rows = s.m_rows; m_cols = s.m_cols; m_data = s.m_data;
-            s.m_rows = 0; s.m_cols = 0; s.m_data = nullptr;
+TEST_SUBMODULE(buffers, m) {
+    // test_from_python / test_to_python:
+    class Matrix {
+    public:
+        Matrix(ssize_t rows, ssize_t cols) : m_rows(rows), m_cols(cols) {
+            print_created(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
+            m_data = new float[(size_t) (rows*cols)];
+            memset(m_data, 0, sizeof(float) * (size_t) (rows * cols));
+        }
+
+        Matrix(const Matrix &s) : m_rows(s.m_rows), m_cols(s.m_cols) {
+            print_copy_created(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
+            m_data = new float[(size_t) (m_rows * m_cols)];
+            memcpy(m_data, s.m_data, sizeof(float) * (size_t) (m_rows * m_cols));
         }
-        return *this;
-    }
 
-    float operator()(size_t i, size_t j) const {
-        return m_data[i*m_cols + j];
-    }
+        Matrix(Matrix &&s) : m_rows(s.m_rows), m_cols(s.m_cols), m_data(s.m_data) {
+            print_move_created(this);
+            s.m_rows = 0;
+            s.m_cols = 0;
+            s.m_data = nullptr;
+        }
+
+        ~Matrix() {
+            print_destroyed(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
+            delete[] m_data;
+        }
 
-    float &operator()(size_t i, size_t j) {
-        return m_data[i*m_cols + j];
-    }
+        Matrix &operator=(const Matrix &s) {
+            print_copy_assigned(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
+            delete[] m_data;
+            m_rows = s.m_rows;
+            m_cols = s.m_cols;
+            m_data = new float[(size_t) (m_rows * m_cols)];
+            memcpy(m_data, s.m_data, sizeof(float) * (size_t) (m_rows * m_cols));
+            return *this;
+        }
 
-    float *data() { return m_data; }
+        Matrix &operator=(Matrix &&s) {
+            print_move_assigned(this, std::to_string(m_rows) + "x" + std::to_string(m_cols) + " matrix");
+            if (&s != this) {
+                delete[] m_data;
+                m_rows = s.m_rows; m_cols = s.m_cols; m_data = s.m_data;
+                s.m_rows = 0; s.m_cols = 0; s.m_data = nullptr;
+            }
+            return *this;
+        }
 
-    size_t rows() const { return m_rows; }
-    size_t cols() const { return m_cols; }
-private:
-    size_t m_rows;
-    size_t m_cols;
-    float *m_data;
-};
+        float operator()(ssize_t i, ssize_t j) const {
+            return m_data[(size_t) (i*m_cols + j)];
+        }
 
-test_initializer buffers([](py::module &m) {
-    py::class_<Matrix> mtx(m, "Matrix", py::buffer_protocol());
+        float &operator()(ssize_t i, ssize_t j) {
+            return m_data[(size_t) (i*m_cols + j)];
+        }
 
-    mtx.def(py::init<size_t, size_t>())
+        float *data() { return m_data; }
+
+        ssize_t rows() const { return m_rows; }
+        ssize_t cols() const { return m_cols; }
+    private:
+        ssize_t m_rows;
+        ssize_t m_cols;
+        float *m_data;
+    };
+    py::class_<Matrix>(m, "Matrix", py::buffer_protocol())
+        .def(py::init<ssize_t, ssize_t>())
         /// Construct from a buffer
-        .def("__init__", [](Matrix &v, py::buffer b) {
+        .def(py::init([](py::buffer b) {
             py::buffer_info info = b.request();
             if (info.format != py::format_descriptor<float>::format() || info.ndim != 2)
                 throw std::runtime_error("Incompatible buffer format!");
-            new (&v) Matrix(info.shape[0], info.shape[1]);
-            memcpy(v.data(), info.ptr, sizeof(float) * v.rows() * v.cols());
-        })
+
+            auto v = new Matrix(info.shape[0], info.shape[1]);
+            memcpy(v->data(), info.ptr, sizeof(float) * (size_t) (v->rows() * v->cols()));
+            return v;
+        }))
 
        .def("rows", &Matrix::rows)
        .def("cols", &Matrix::cols)
 
         /// Bare bones interface
-       .def("__getitem__", [](const Matrix &m, std::pair<size_t, size_t> i) {
+       .def("__getitem__", [](const Matrix &m, std::pair<ssize_t, ssize_t> i) {
             if (i.first >= m.rows() || i.second >= m.cols())
                 throw py::index_error();
             return m(i.first, i.second);
         })
-       .def("__setitem__", [](Matrix &m, std::pair<size_t, size_t> i, float v) {
+       .def("__setitem__", [](Matrix &m, std::pair<ssize_t, ssize_t> i, float v) {
             if (i.first >= m.rows() || i.second >= m.cols())
                 throw py::index_error();
             m(i.first, i.second) = v;
@@ -105,13 +106,64 @@ test_initializer buffers([](py::module &m) {
        .def_buffer([](Matrix &m) -> py::buffer_info {
             return py::buffer_info(
                 m.data(),                               /* Pointer to buffer */
-                sizeof(float),                          /* Size of one scalar */
-                py::format_descriptor<float>::format(), /* Python struct-style format descriptor */
-                2,                                      /* Number of dimensions */
                 { m.rows(), m.cols() },                 /* Buffer dimensions */
-                { sizeof(float) * m.rows(),             /* Strides (in bytes) for each index */
+                { sizeof(float) * size_t(m.rows()),     /* Strides (in bytes) for each index */
                   sizeof(float) }
             );
         })
         ;
-});
+
+
+    // test_inherited_protocol
+    class SquareMatrix : public Matrix {
+    public:
+        SquareMatrix(ssize_t n) : Matrix(n, n) { }
+    };
+    // Derived classes inherit the buffer protocol and the buffer access function
+    py::class_<SquareMatrix, Matrix>(m, "SquareMatrix")
+        .def(py::init<ssize_t>());
+
+
+    // test_pointer_to_member_fn
+    // Tests that passing a pointer to member to the base class works in
+    // the derived class.
+    struct Buffer {
+        int32_t value = 0;
+
+        py::buffer_info get_buffer_info() {
+            return py::buffer_info(&value, sizeof(value),
+                                   py::format_descriptor<int32_t>::format(), 1);
+        }
+    };
+    py::class_<Buffer>(m, "Buffer", py::buffer_protocol())
+        .def(py::init<>())
+        .def_readwrite("value", &Buffer::value)
+        .def_buffer(&Buffer::get_buffer_info);
+
+
+    class ConstBuffer {
+        std::unique_ptr<int32_t> value;
+
+    public:
+        int32_t get_value() const { return *value; }
+        void set_value(int32_t v) { *value = v; }
+
+        py::buffer_info get_buffer_info() const {
+            return py::buffer_info(value.get(), sizeof(*value),
+                                   py::format_descriptor<int32_t>::format(), 1);
+        }
+
+        ConstBuffer() : value(new int32_t{0}) { };
+    };
+    py::class_<ConstBuffer>(m, "ConstBuffer", py::buffer_protocol())
+        .def(py::init<>())
+        .def_property("value", &ConstBuffer::get_value, &ConstBuffer::set_value)
+        .def_buffer(&ConstBuffer::get_buffer_info);
+
+    struct DerivedBuffer : public Buffer { };
+    py::class_<DerivedBuffer>(m, "DerivedBuffer", py::buffer_protocol())
+        .def(py::init<>())
+        .def_readwrite("value", (int32_t DerivedBuffer::*) &DerivedBuffer::value)
+        .def_buffer(&DerivedBuffer::get_buffer_info);
+
+}
diff --git a/ext/pybind11/tests/test_buffers.py b/ext/pybind11/tests/test_buffers.py
index 24843d95a..c348be5dd 100644
--- a/ext/pybind11/tests/test_buffers.py
+++ b/ext/pybind11/tests/test_buffers.py
@@ -1,5 +1,7 @@
+import struct
 import pytest
-from pybind11_tests import Matrix, ConstructorStats
+from pybind11_tests import buffers as m
+from pybind11_tests import ConstructorStats
 
 pytestmark = pytest.requires_numpy
 
@@ -9,17 +11,17 @@ with pytest.suppress(ImportError):
 
 def test_from_python():
     with pytest.raises(RuntimeError) as excinfo:
-        Matrix(np.array([1, 2, 3]))  # trying to assign a 1D array
+        m.Matrix(np.array([1, 2, 3]))  # trying to assign a 1D array
     assert str(excinfo.value) == "Incompatible buffer format!"
 
     m3 = np.array([[1, 2, 3], [4, 5, 6]]).astype(np.float32)
-    m4 = Matrix(m3)
+    m4 = m.Matrix(m3)
 
     for i in range(m4.rows()):
         for j in range(m4.cols()):
             assert m3[i, j] == m4[i, j]
 
-    cstats = ConstructorStats.get(Matrix)
+    cstats = ConstructorStats.get(m.Matrix)
     assert cstats.alive() == 1
     del m3, m4
     assert cstats.alive() == 0
@@ -34,25 +36,26 @@ def test_from_python():
 # https://bitbucket.org/pypy/pypy/issues/2444
 @pytest.unsupported_on_pypy
 def test_to_python():
-    m = Matrix(5, 5)
+    mat = m.Matrix(5, 5)
+    assert memoryview(mat).shape == (5, 5)
 
-    assert m[2, 3] == 0
-    m[2, 3] = 4
-    assert m[2, 3] == 4
+    assert mat[2, 3] == 0
+    mat[2, 3] = 4
+    assert mat[2, 3] == 4
 
-    m2 = np.array(m, copy=False)
-    assert m2.shape == (5, 5)
-    assert abs(m2).sum() == 4
-    assert m2[2, 3] == 4
-    m2[2, 3] = 5
-    assert m2[2, 3] == 5
+    mat2 = np.array(mat, copy=False)
+    assert mat2.shape == (5, 5)
+    assert abs(mat2).sum() == 4
+    assert mat2[2, 3] == 4
+    mat2[2, 3] = 5
+    assert mat2[2, 3] == 5
 
-    cstats = ConstructorStats.get(Matrix)
+    cstats = ConstructorStats.get(m.Matrix)
     assert cstats.alive() == 1
-    del m
+    del mat
     pytest.gc_collect()
     assert cstats.alive() == 1
-    del m2  # holds an m reference
+    del mat2  # holds a mat reference
     pytest.gc_collect()
     assert cstats.alive() == 0
     assert cstats.values() == ["5x5 matrix"]
@@ -60,3 +63,21 @@ def test_to_python():
     # assert cstats.move_constructions >= 0  # Don't invoke any
     assert cstats.copy_assignments == 0
     assert cstats.move_assignments == 0
+
+
+@pytest.unsupported_on_pypy
+def test_inherited_protocol():
+    """SquareMatrix is derived from Matrix and inherits the buffer protocol"""
+
+    matrix = m.SquareMatrix(5)
+    assert memoryview(matrix).shape == (5, 5)
+    assert np.asarray(matrix).shape == (5, 5)
+
+
+@pytest.unsupported_on_pypy
+def test_pointer_to_member_fn():
+    for cls in [m.Buffer, m.ConstBuffer, m.DerivedBuffer]:
+        buf = cls()
+        buf.value = 0x12345678
+        value = struct.unpack('i', bytearray(buf))[0]
+        assert value == 0x12345678
diff --git a/ext/pybind11/tests/test_builtin_casters.cpp b/ext/pybind11/tests/test_builtin_casters.cpp
new file mode 100644
index 000000000..b73e96ea5
--- /dev/null
+++ b/ext/pybind11/tests/test_builtin_casters.cpp
@@ -0,0 +1,156 @@
+/*
+    tests/test_builtin_casters.cpp -- Casters available without any additional headers
+
+    Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include <pybind11/complex.h>
+
+#if defined(_MSC_VER)
+#  pragma warning(push)
+#  pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
+#endif
+
+TEST_SUBMODULE(builtin_casters, m) {
+    // test_simple_string
+    m.def("string_roundtrip", [](const char *s) { return s; });
+
+    // test_unicode_conversion
+    // Some test characters in utf16 and utf32 encodings.  The last one (the 𝐀) contains a null byte
+    char32_t a32 = 0x61 /*a*/, z32 = 0x7a /*z*/, ib32 = 0x203d /*‽*/, cake32 = 0x1f382 /*🎂*/,              mathbfA32 = 0x1d400 /*𝐀*/;
+    char16_t b16 = 0x62 /*b*/, z16 = 0x7a,       ib16 = 0x203d,       cake16_1 = 0xd83c, cake16_2 = 0xdf82, mathbfA16_1 = 0xd835, mathbfA16_2 = 0xdc00;
+    std::wstring wstr;
+    wstr.push_back(0x61); // a
+    wstr.push_back(0x2e18); // ⸘
+    if (sizeof(wchar_t) == 2) { wstr.push_back(mathbfA16_1); wstr.push_back(mathbfA16_2); } // 𝐀, utf16
+    else { wstr.push_back((wchar_t) mathbfA32); } // 𝐀, utf32
+    wstr.push_back(0x7a); // z
+
+    m.def("good_utf8_string", []() { return std::string(u8"Say utf8\u203d \U0001f382 \U0001d400"); }); // Say utf8‽ 🎂 𝐀
+    m.def("good_utf16_string", [=]() { return std::u16string({ b16, ib16, cake16_1, cake16_2, mathbfA16_1, mathbfA16_2, z16 }); }); // b‽🎂𝐀z
+    m.def("good_utf32_string", [=]() { return std::u32string({ a32, mathbfA32, cake32, ib32, z32 }); }); // a𝐀🎂‽z
+    m.def("good_wchar_string", [=]() { return wstr; }); // a‽𝐀z
+    m.def("bad_utf8_string", []()  { return std::string("abc\xd0" "def"); });
+    m.def("bad_utf16_string", [=]() { return std::u16string({ b16, char16_t(0xd800), z16 }); });
+    // Under Python 2.7, invalid unicode UTF-32 characters don't appear to trigger UnicodeDecodeError
+    if (PY_MAJOR_VERSION >= 3)
+        m.def("bad_utf32_string", [=]() { return std::u32string({ a32, char32_t(0xd800), z32 }); });
+    if (PY_MAJOR_VERSION >= 3 || sizeof(wchar_t) == 2)
+        m.def("bad_wchar_string", [=]() { return std::wstring({ wchar_t(0x61), wchar_t(0xd800) }); });
+    m.def("u8_Z", []() -> char { return 'Z'; });
+    m.def("u8_eacute", []() -> char { return '\xe9'; });
+    m.def("u16_ibang", [=]() -> char16_t { return ib16; });
+    m.def("u32_mathbfA", [=]() -> char32_t { return mathbfA32; });
+    m.def("wchar_heart", []() -> wchar_t { return 0x2665; });
+
+    // test_single_char_arguments
+    m.attr("wchar_size") = py::cast(sizeof(wchar_t));
+    m.def("ord_char", [](char c) -> int { return static_cast<unsigned char>(c); });
+    m.def("ord_char16", [](char16_t c) -> uint16_t { return c; });
+    m.def("ord_char32", [](char32_t c) -> uint32_t { return c; });
+    m.def("ord_wchar", [](wchar_t c) -> int { return c; });
+
+    // test_bytes_to_string
+    m.def("strlen", [](char *s) { return strlen(s); });
+    m.def("string_length", [](std::string s) { return s.length(); });
+
+    // test_string_view
+#ifdef PYBIND11_HAS_STRING_VIEW
+    m.attr("has_string_view") = true;
+    m.def("string_view_print",   [](std::string_view s)    { py::print(s, s.size()); });
+    m.def("string_view16_print", [](std::u16string_view s) { py::print(s, s.size()); });
+    m.def("string_view32_print", [](std::u32string_view s) { py::print(s, s.size()); });
+    m.def("string_view_chars",   [](std::string_view s)    { py::list l; for (auto c : s) l.append((std::uint8_t) c); return l; });
+    m.def("string_view16_chars", [](std::u16string_view s) { py::list l; for (auto c : s) l.append((int) c); return l; });
+    m.def("string_view32_chars", [](std::u32string_view s) { py::list l; for (auto c : s) l.append((int) c); return l; });
+    m.def("string_view_return",   []() { return std::string_view(u8"utf8 secret \U0001f382"); });
+    m.def("string_view16_return", []() { return std::u16string_view(u"utf16 secret \U0001f382"); });
+    m.def("string_view32_return", []() { return std::u32string_view(U"utf32 secret \U0001f382"); });
+#endif
+
+    // test_integer_casting
+    m.def("i32_str", [](std::int32_t v) { return std::to_string(v); });
+    m.def("u32_str", [](std::uint32_t v) { return std::to_string(v); });
+    m.def("i64_str", [](std::int64_t v) { return std::to_string(v); });
+    m.def("u64_str", [](std::uint64_t v) { return std::to_string(v); });
+
+    // test_tuple
+    m.def("pair_passthrough", [](std::pair<bool, std::string> input) {
+        return std::make_pair(input.second, input.first);
+    }, "Return a pair in reversed order");
+    m.def("tuple_passthrough", [](std::tuple<bool, std::string, int> input) {
+        return std::make_tuple(std::get<2>(input), std::get<1>(input), std::get<0>(input));
+    }, "Return a triple in reversed order");
+    m.def("empty_tuple", []() { return std::tuple<>(); });
+    static std::pair<RValueCaster, RValueCaster> lvpair;
+    static std::tuple<RValueCaster, RValueCaster, RValueCaster> lvtuple;
+    static std::pair<RValueCaster, std::tuple<RValueCaster, std::pair<RValueCaster, RValueCaster>>> lvnested;
+    m.def("rvalue_pair", []() { return std::make_pair(RValueCaster{}, RValueCaster{}); });
+    m.def("lvalue_pair", []() -> const decltype(lvpair) & { return lvpair; });
+    m.def("rvalue_tuple", []() { return std::make_tuple(RValueCaster{}, RValueCaster{}, RValueCaster{}); });
+    m.def("lvalue_tuple", []() -> const decltype(lvtuple) & { return lvtuple; });
+    m.def("rvalue_nested", []() {
+        return std::make_pair(RValueCaster{}, std::make_tuple(RValueCaster{}, std::make_pair(RValueCaster{}, RValueCaster{}))); });
+    m.def("lvalue_nested", []() -> const decltype(lvnested) & { return lvnested; });
+
+    // test_builtins_cast_return_none
+    m.def("return_none_string", []() -> std::string * { return nullptr; });
+    m.def("return_none_char",   []() -> const char *  { return nullptr; });
+    m.def("return_none_bool",   []() -> bool *        { return nullptr; });
+    m.def("return_none_int",    []() -> int *         { return nullptr; });
+    m.def("return_none_float",  []() -> float *       { return nullptr; });
+
+    // test_none_deferred
+    m.def("defer_none_cstring", [](char *) { return false; });
+    m.def("defer_none_cstring", [](py::none) { return true; });
+    m.def("defer_none_custom", [](UserType *) { return false; });
+    m.def("defer_none_custom", [](py::none) { return true; });
+    m.def("nodefer_none_void", [](void *) { return true; });
+    m.def("nodefer_none_void", [](py::none) { return false; });
+
+    // test_void_caster
+    m.def("load_nullptr_t", [](std::nullptr_t) {}); // not useful, but it should still compile
+    m.def("cast_nullptr_t", []() { return std::nullptr_t{}; });
+
+    // test_bool_caster
+    m.def("bool_passthrough", [](bool arg) { return arg; });
+    m.def("bool_passthrough_noconvert", [](bool arg) { return arg; }, py::arg().noconvert());
+
+    // test_reference_wrapper
+    m.def("refwrap_builtin", [](std::reference_wrapper<int> p) { return 10 * p.get(); });
+    m.def("refwrap_usertype", [](std::reference_wrapper<UserType> p) { return p.get().value(); });
+    // Not currently supported (std::pair caster has return-by-value cast operator);
+    // triggers static_assert failure.
+    //m.def("refwrap_pair", [](std::reference_wrapper<std::pair<int, int>>) { });
+
+    m.def("refwrap_list", [](bool copy) {
+        static IncType x1(1), x2(2);
+        py::list l;
+        for (auto &f : {std::ref(x1), std::ref(x2)}) {
+            l.append(py::cast(f, copy ? py::return_value_policy::copy
+                                      : py::return_value_policy::reference));
+        }
+        return l;
+    }, "copy"_a);
+
+    m.def("refwrap_iiw", [](const IncType &w) { return w.value(); });
+    m.def("refwrap_call_iiw", [](IncType &w, py::function f) {
+        py::list l;
+        l.append(f(std::ref(w)));
+        l.append(f(std::cref(w)));
+        IncType x(w.value());
+        l.append(f(std::ref(x)));
+        IncType y(w.value());
+        auto r3 = std::ref(y);
+        l.append(f(r3));
+        return l;
+    });
+
+    // test_complex
+    m.def("complex_cast", [](float x) { return "{}"_s.format(x); });
+    m.def("complex_cast", [](std::complex<float> x) { return "({}, {})"_s.format(x.real(), x.imag()); });
+}
diff --git a/ext/pybind11/tests/test_builtin_casters.py b/ext/pybind11/tests/test_builtin_casters.py
new file mode 100644
index 000000000..bc094a381
--- /dev/null
+++ b/ext/pybind11/tests/test_builtin_casters.py
@@ -0,0 +1,322 @@
+# Python < 3 needs this: coding=utf-8
+import pytest
+
+from pybind11_tests import builtin_casters as m
+from pybind11_tests import UserType, IncType
+
+
+def test_simple_string():
+    assert m.string_roundtrip("const char *") == "const char *"
+
+
+def test_unicode_conversion():
+    """Tests unicode conversion and error reporting."""
+    assert m.good_utf8_string() == u"Say utf8‽ 🎂 𝐀"
+    assert m.good_utf16_string() == u"b‽🎂𝐀z"
+    assert m.good_utf32_string() == u"a𝐀🎂‽z"
+    assert m.good_wchar_string() == u"a⸘𝐀z"
+
+    with pytest.raises(UnicodeDecodeError):
+        m.bad_utf8_string()
+
+    with pytest.raises(UnicodeDecodeError):
+        m.bad_utf16_string()
+
+    # These are provided only if they actually fail (they don't when 32-bit and under Python 2.7)
+    if hasattr(m, "bad_utf32_string"):
+        with pytest.raises(UnicodeDecodeError):
+            m.bad_utf32_string()
+    if hasattr(m, "bad_wchar_string"):
+        with pytest.raises(UnicodeDecodeError):
+            m.bad_wchar_string()
+
+    assert m.u8_Z() == 'Z'
+    assert m.u8_eacute() == u'é'
+    assert m.u16_ibang() == u'‽'
+    assert m.u32_mathbfA() == u'𝐀'
+    assert m.wchar_heart() == u'♥'
+
+
+def test_single_char_arguments():
+    """Tests failures for passing invalid inputs to char-accepting functions"""
+    def toobig_message(r):
+        return "Character code point not in range({0:#x})".format(r)
+    toolong_message = "Expected a character, but multi-character string found"
+
+    assert m.ord_char(u'a') == 0x61  # simple ASCII
+    assert m.ord_char(u'é') == 0xE9  # requires 2 bytes in utf-8, but can be stuffed in a char
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_char(u'Ā') == 0x100  # requires 2 bytes, doesn't fit in a char
+    assert str(excinfo.value) == toobig_message(0x100)
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_char(u'ab')
+    assert str(excinfo.value) == toolong_message
+
+    assert m.ord_char16(u'a') == 0x61
+    assert m.ord_char16(u'é') == 0xE9
+    assert m.ord_char16(u'Ā') == 0x100
+    assert m.ord_char16(u'‽') == 0x203d
+    assert m.ord_char16(u'♥') == 0x2665
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_char16(u'🎂') == 0x1F382  # requires surrogate pair
+    assert str(excinfo.value) == toobig_message(0x10000)
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_char16(u'aa')
+    assert str(excinfo.value) == toolong_message
+
+    assert m.ord_char32(u'a') == 0x61
+    assert m.ord_char32(u'é') == 0xE9
+    assert m.ord_char32(u'Ā') == 0x100
+    assert m.ord_char32(u'‽') == 0x203d
+    assert m.ord_char32(u'♥') == 0x2665
+    assert m.ord_char32(u'🎂') == 0x1F382
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_char32(u'aa')
+    assert str(excinfo.value) == toolong_message
+
+    assert m.ord_wchar(u'a') == 0x61
+    assert m.ord_wchar(u'é') == 0xE9
+    assert m.ord_wchar(u'Ā') == 0x100
+    assert m.ord_wchar(u'‽') == 0x203d
+    assert m.ord_wchar(u'♥') == 0x2665
+    if m.wchar_size == 2:
+        with pytest.raises(ValueError) as excinfo:
+            assert m.ord_wchar(u'🎂') == 0x1F382  # requires surrogate pair
+        assert str(excinfo.value) == toobig_message(0x10000)
+    else:
+        assert m.ord_wchar(u'🎂') == 0x1F382
+    with pytest.raises(ValueError) as excinfo:
+        assert m.ord_wchar(u'aa')
+    assert str(excinfo.value) == toolong_message
+
+
+def test_bytes_to_string():
+    """Tests the ability to pass bytes to C++ string-accepting functions.  Note that this is
+    one-way: the only way to return bytes to Python is via the pybind11::bytes class."""
+    # Issue #816
+    import sys
+    byte = bytes if sys.version_info[0] < 3 else str
+
+    assert m.strlen(byte("hi")) == 2
+    assert m.string_length(byte("world")) == 5
+    assert m.string_length(byte("a\x00b")) == 3
+    assert m.strlen(byte("a\x00b")) == 1  # C-string limitation
+
+    # passing in a utf8 encoded string should work
+    assert m.string_length(u'💩'.encode("utf8")) == 4
+
+
+@pytest.mark.skipif(not hasattr(m, "has_string_view"), reason="no <string_view>")
+def test_string_view(capture):
+    """Tests support for C++17 string_view arguments and return values"""
+    assert m.string_view_chars("Hi") == [72, 105]
+    assert m.string_view_chars("Hi 🎂") == [72, 105, 32, 0xf0, 0x9f, 0x8e, 0x82]
+    assert m.string_view16_chars("Hi 🎂") == [72, 105, 32, 0xd83c, 0xdf82]
+    assert m.string_view32_chars("Hi 🎂") == [72, 105, 32, 127874]
+
+    assert m.string_view_return() == "utf8 secret 🎂"
+    assert m.string_view16_return() == "utf16 secret 🎂"
+    assert m.string_view32_return() == "utf32 secret 🎂"
+
+    with capture:
+        m.string_view_print("Hi")
+        m.string_view_print("utf8 🎂")
+        m.string_view16_print("utf16 🎂")
+        m.string_view32_print("utf32 🎂")
+    assert capture == """
+        Hi 2
+        utf8 🎂 9
+        utf16 🎂 8
+        utf32 🎂 7
+    """
+
+    with capture:
+        m.string_view_print("Hi, ascii")
+        m.string_view_print("Hi, utf8 🎂")
+        m.string_view16_print("Hi, utf16 🎂")
+        m.string_view32_print("Hi, utf32 🎂")
+    assert capture == """
+        Hi, ascii 9
+        Hi, utf8 🎂 13
+        Hi, utf16 🎂 12
+        Hi, utf32 🎂 11
+    """
+
+
+def test_integer_casting():
+    """Issue #929 - out-of-range integer values shouldn't be accepted"""
+    import sys
+    assert m.i32_str(-1) == "-1"
+    assert m.i64_str(-1) == "-1"
+    assert m.i32_str(2000000000) == "2000000000"
+    assert m.u32_str(2000000000) == "2000000000"
+    if sys.version_info < (3,):
+        assert m.i32_str(long(-1)) == "-1"  # noqa: F821 undefined name 'long'
+        assert m.i64_str(long(-1)) == "-1"  # noqa: F821 undefined name 'long'
+        assert m.i64_str(long(-999999999999)) == "-999999999999"  # noqa: F821 undefined name
+        assert m.u64_str(long(999999999999)) == "999999999999"  # noqa: F821 undefined name 'long'
+    else:
+        assert m.i64_str(-999999999999) == "-999999999999"
+        assert m.u64_str(999999999999) == "999999999999"
+
+    with pytest.raises(TypeError) as excinfo:
+        m.u32_str(-1)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.u64_str(-1)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.i32_str(-3000000000)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.i32_str(3000000000)
+    assert "incompatible function arguments" in str(excinfo.value)
+
+    if sys.version_info < (3,):
+        with pytest.raises(TypeError) as excinfo:
+            m.u32_str(long(-1))  # noqa: F821 undefined name 'long'
+        assert "incompatible function arguments" in str(excinfo.value)
+        with pytest.raises(TypeError) as excinfo:
+            m.u64_str(long(-1))  # noqa: F821 undefined name 'long'
+        assert "incompatible function arguments" in str(excinfo.value)
+
+
+def test_tuple(doc):
+    """std::pair <-> tuple & std::tuple <-> tuple"""
+    assert m.pair_passthrough((True, "test")) == ("test", True)
+    assert m.tuple_passthrough((True, "test", 5)) == (5, "test", True)
+    # Any sequence can be cast to a std::pair or std::tuple
+    assert m.pair_passthrough([True, "test"]) == ("test", True)
+    assert m.tuple_passthrough([True, "test", 5]) == (5, "test", True)
+    assert m.empty_tuple() == ()
+
+    assert doc(m.pair_passthrough) == """
+        pair_passthrough(arg0: Tuple[bool, str]) -> Tuple[str, bool]
+
+        Return a pair in reversed order
+    """
+    assert doc(m.tuple_passthrough) == """
+        tuple_passthrough(arg0: Tuple[bool, str, int]) -> Tuple[int, str, bool]
+
+        Return a triple in reversed order
+    """
+
+    assert m.rvalue_pair() == ("rvalue", "rvalue")
+    assert m.lvalue_pair() == ("lvalue", "lvalue")
+    assert m.rvalue_tuple() == ("rvalue", "rvalue", "rvalue")
+    assert m.lvalue_tuple() == ("lvalue", "lvalue", "lvalue")
+    assert m.rvalue_nested() == ("rvalue", ("rvalue", ("rvalue", "rvalue")))
+    assert m.lvalue_nested() == ("lvalue", ("lvalue", ("lvalue", "lvalue")))
+
+
+def test_builtins_cast_return_none():
+    """Casters produced with PYBIND11_TYPE_CASTER() should convert nullptr to None"""
+    assert m.return_none_string() is None
+    assert m.return_none_char() is None
+    assert m.return_none_bool() is None
+    assert m.return_none_int() is None
+    assert m.return_none_float() is None
+
+
+def test_none_deferred():
+    """None passed as various argument types should defer to other overloads"""
+    assert not m.defer_none_cstring("abc")
+    assert m.defer_none_cstring(None)
+    assert not m.defer_none_custom(UserType())
+    assert m.defer_none_custom(None)
+    assert m.nodefer_none_void(None)
+
+
+def test_void_caster():
+    assert m.load_nullptr_t(None) is None
+    assert m.cast_nullptr_t() is None
+
+
+def test_reference_wrapper():
+    """std::reference_wrapper for builtin and user types"""
+    assert m.refwrap_builtin(42) == 420
+    assert m.refwrap_usertype(UserType(42)) == 42
+
+    with pytest.raises(TypeError) as excinfo:
+        m.refwrap_builtin(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+
+    with pytest.raises(TypeError) as excinfo:
+        m.refwrap_usertype(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+
+    a1 = m.refwrap_list(copy=True)
+    a2 = m.refwrap_list(copy=True)
+    assert [x.value for x in a1] == [2, 3]
+    assert [x.value for x in a2] == [2, 3]
+    assert not a1[0] is a2[0] and not a1[1] is a2[1]
+
+    b1 = m.refwrap_list(copy=False)
+    b2 = m.refwrap_list(copy=False)
+    assert [x.value for x in b1] == [1, 2]
+    assert [x.value for x in b2] == [1, 2]
+    assert b1[0] is b2[0] and b1[1] is b2[1]
+
+    assert m.refwrap_iiw(IncType(5)) == 5
+    assert m.refwrap_call_iiw(IncType(10), m.refwrap_iiw) == [10, 10, 10, 10]
+
+
+def test_complex_cast():
+    """std::complex casts"""
+    assert m.complex_cast(1) == "1.0"
+    assert m.complex_cast(2j) == "(0.0, 2.0)"
+
+
+def test_bool_caster():
+    """Test bool caster implicit conversions."""
+    convert, noconvert = m.bool_passthrough, m.bool_passthrough_noconvert
+
+    def require_implicit(v):
+        pytest.raises(TypeError, noconvert, v)
+
+    def cant_convert(v):
+        pytest.raises(TypeError, convert, v)
+
+    # straight up bool
+    assert convert(True) is True
+    assert convert(False) is False
+    assert noconvert(True) is True
+    assert noconvert(False) is False
+
+    # None requires implicit conversion
+    require_implicit(None)
+    assert convert(None) is False
+
+    class A(object):
+        def __init__(self, x):
+            self.x = x
+
+        def __nonzero__(self):
+            return self.x
+
+        def __bool__(self):
+            return self.x
+
+    class B(object):
+        pass
+
+    # Arbitrary objects are not accepted
+    cant_convert(object())
+    cant_convert(B())
+
+    # Objects with __nonzero__ / __bool__ defined can be converted
+    require_implicit(A(True))
+    assert convert(A(True)) is True
+    assert convert(A(False)) is False
+
+
+@pytest.requires_numpy
+def test_numpy_bool():
+    import numpy as np
+    convert, noconvert = m.bool_passthrough, m.bool_passthrough_noconvert
+
+    # np.bool_ is not considered implicit
+    assert convert(np.bool_(True)) is True
+    assert convert(np.bool_(False)) is False
+    assert noconvert(np.bool_(True)) is True
+    assert noconvert(np.bool_(False)) is False
diff --git a/ext/pybind11/tests/test_call_policies.cpp b/ext/pybind11/tests/test_call_policies.cpp
new file mode 100644
index 000000000..8642188f9
--- /dev/null
+++ b/ext/pybind11/tests/test_call_policies.cpp
@@ -0,0 +1,98 @@
+/*
+    tests/test_call_policies.cpp -- keep_alive and call_guard
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+
+struct CustomGuard {
+    static bool enabled;
+
+    CustomGuard() { enabled = true; }
+    ~CustomGuard() { enabled = false; }
+
+    static const char *report_status() { return enabled ? "guarded" : "unguarded"; }
+};
+bool CustomGuard::enabled = false;
+
+struct DependentGuard {
+    static bool enabled;
+
+    DependentGuard() { enabled = CustomGuard::enabled; }
+    ~DependentGuard() { enabled = false; }
+
+    static const char *report_status() { return enabled ? "guarded" : "unguarded"; }
+};
+bool DependentGuard::enabled = false;
+
+TEST_SUBMODULE(call_policies, m) {
+    // Parent/Child are used in:
+    // test_keep_alive_argument, test_keep_alive_return_value, test_alive_gc_derived,
+    // test_alive_gc_multi_derived, test_return_none, test_keep_alive_constructor
+    class Child {
+    public:
+        Child() { py::print("Allocating child."); }
+        ~Child() { py::print("Releasing child."); }
+    };
+    py::class_<Child>(m, "Child")
+        .def(py::init<>());
+
+    class Parent {
+    public:
+        Parent() { py::print("Allocating parent."); }
+        ~Parent() { py::print("Releasing parent."); }
+        void addChild(Child *) { }
+        Child *returnChild() { return new Child(); }
+        Child *returnNullChild() { return nullptr; }
+    };
+    py::class_<Parent>(m, "Parent")
+        .def(py::init<>())
+        .def(py::init([](Child *) { return new Parent(); }), py::keep_alive<1, 2>())
+        .def("addChild", &Parent::addChild)
+        .def("addChildKeepAlive", &Parent::addChild, py::keep_alive<1, 2>())
+        .def("returnChild", &Parent::returnChild)
+        .def("returnChildKeepAlive", &Parent::returnChild, py::keep_alive<1, 0>())
+        .def("returnNullChildKeepAliveChild", &Parent::returnNullChild, py::keep_alive<1, 0>())
+        .def("returnNullChildKeepAliveParent", &Parent::returnNullChild, py::keep_alive<0, 1>());
+
+#if !defined(PYPY_VERSION)
+    // test_alive_gc
+    class ParentGC : public Parent {
+    public:
+        using Parent::Parent;
+    };
+    py::class_<ParentGC, Parent>(m, "ParentGC", py::dynamic_attr())
+        .def(py::init<>());
+#endif
+
+    // test_call_guard
+    m.def("unguarded_call", &CustomGuard::report_status);
+    m.def("guarded_call", &CustomGuard::report_status, py::call_guard<CustomGuard>());
+
+    m.def("multiple_guards_correct_order", []() {
+        return CustomGuard::report_status() + std::string(" & ") + DependentGuard::report_status();
+    }, py::call_guard<CustomGuard, DependentGuard>());
+
+    m.def("multiple_guards_wrong_order", []() {
+        return DependentGuard::report_status() + std::string(" & ") + CustomGuard::report_status();
+    }, py::call_guard<DependentGuard, CustomGuard>());
+
+#if defined(WITH_THREAD) && !defined(PYPY_VERSION)
+    // `py::call_guard<py::gil_scoped_release>()` should work in PyPy as well,
+    // but it's unclear how to test it without `PyGILState_GetThisThreadState`.
+    auto report_gil_status = []() {
+        auto is_gil_held = false;
+        if (auto tstate = py::detail::get_thread_state_unchecked())
+            is_gil_held = (tstate == PyGILState_GetThisThreadState());
+
+        return is_gil_held ? "GIL held" : "GIL released";
+    };
+
+    m.def("with_gil", report_gil_status);
+    m.def("without_gil", report_gil_status, py::call_guard<py::gil_scoped_release>());
+#endif
+}
diff --git a/ext/pybind11/tests/test_call_policies.py b/ext/pybind11/tests/test_call_policies.py
new file mode 100644
index 000000000..7c835599c
--- /dev/null
+++ b/ext/pybind11/tests/test_call_policies.py
@@ -0,0 +1,187 @@
+import pytest
+from pybind11_tests import call_policies as m
+from pybind11_tests import ConstructorStats
+
+
+def test_keep_alive_argument(capture):
+    n_inst = ConstructorStats.detail_reg_inst()
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.addChild(m.Child())
+        assert ConstructorStats.detail_reg_inst() == n_inst + 1
+    assert capture == """
+        Allocating child.
+        Releasing child.
+    """
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == "Releasing parent."
+
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.addChildKeepAlive(m.Child())
+        assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    assert capture == "Allocating child."
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+    """
+
+
+def test_keep_alive_return_value(capture):
+    n_inst = ConstructorStats.detail_reg_inst()
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.returnChild()
+        assert ConstructorStats.detail_reg_inst() == n_inst + 1
+    assert capture == """
+        Allocating child.
+        Releasing child.
+    """
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == "Releasing parent."
+
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.returnChildKeepAlive()
+        assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    assert capture == "Allocating child."
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+    """
+
+
+# https://bitbucket.org/pypy/pypy/issues/2447
+@pytest.unsupported_on_pypy
+def test_alive_gc(capture):
+    n_inst = ConstructorStats.detail_reg_inst()
+    p = m.ParentGC()
+    p.addChildKeepAlive(m.Child())
+    assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    lst = [p]
+    lst.append(lst)   # creates a circular reference
+    with capture:
+        del p, lst
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+    """
+
+
+def test_alive_gc_derived(capture):
+    class Derived(m.Parent):
+        pass
+
+    n_inst = ConstructorStats.detail_reg_inst()
+    p = Derived()
+    p.addChildKeepAlive(m.Child())
+    assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    lst = [p]
+    lst.append(lst)   # creates a circular reference
+    with capture:
+        del p, lst
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+    """
+
+
+def test_alive_gc_multi_derived(capture):
+    class Derived(m.Parent, m.Child):
+        def __init__(self):
+            m.Parent.__init__(self)
+            m.Child.__init__(self)
+
+    n_inst = ConstructorStats.detail_reg_inst()
+    p = Derived()
+    p.addChildKeepAlive(m.Child())
+    # +3 rather than +2 because Derived corresponds to two registered instances
+    assert ConstructorStats.detail_reg_inst() == n_inst + 3
+    lst = [p]
+    lst.append(lst)   # creates a circular reference
+    with capture:
+        del p, lst
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+        Releasing child.
+    """
+
+
+def test_return_none(capture):
+    n_inst = ConstructorStats.detail_reg_inst()
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.returnNullChildKeepAliveChild()
+        assert ConstructorStats.detail_reg_inst() == n_inst + 1
+    assert capture == ""
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == "Releasing parent."
+
+    with capture:
+        p = m.Parent()
+    assert capture == "Allocating parent."
+    with capture:
+        p.returnNullChildKeepAliveParent()
+        assert ConstructorStats.detail_reg_inst() == n_inst + 1
+    assert capture == ""
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == "Releasing parent."
+
+
+def test_keep_alive_constructor(capture):
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    with capture:
+        p = m.Parent(m.Child())
+        assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    assert capture == """
+        Allocating child.
+        Allocating parent.
+    """
+    with capture:
+        del p
+        assert ConstructorStats.detail_reg_inst() == n_inst
+    assert capture == """
+        Releasing parent.
+        Releasing child.
+    """
+
+
+def test_call_guard():
+    assert m.unguarded_call() == "unguarded"
+    assert m.guarded_call() == "guarded"
+
+    assert m.multiple_guards_correct_order() == "guarded & guarded"
+    assert m.multiple_guards_wrong_order() == "unguarded & guarded"
+
+    if hasattr(m, "with_gil"):
+        assert m.with_gil() == "GIL held"
+        assert m.without_gil() == "GIL released"
diff --git a/ext/pybind11/tests/test_callbacks.cpp b/ext/pybind11/tests/test_callbacks.cpp
index f89cc1c79..273eacc30 100644
--- a/ext/pybind11/tests/test_callbacks.cpp
+++ b/ext/pybind11/tests/test_callbacks.cpp
@@ -12,97 +12,20 @@
 #include <pybind11/functional.h>
 
 
-py::object test_callback1(py::object func) {
-    return func();
-}
-
-py::tuple test_callback2(py::object func) {
-    return func("Hello", 'x', true, 5);
-}
-
-std::string test_callback3(const std::function<int(int)> &func) {
-    return "func(43) = " + std::to_string(func(43));
-}
-
-std::function<int(int)> test_callback4() {
-    return [](int i) { return i+1; };
-}
-
-py::cpp_function test_callback5() {
-    return py::cpp_function([](int i) { return i+1; },
-       py::arg("number"));
-}
-
 int dummy_function(int i) { return i + 1; }
-int dummy_function2(int i, int j) { return i + j; }
-std::function<int(int)> roundtrip(std::function<int(int)> f, bool expect_none = false) {
-    if (expect_none && f) {
-        throw std::runtime_error("Expected None to be converted to empty std::function");
-    }
-    return f;
-}
 
-std::string test_dummy_function(const std::function<int(int)> &f) {
-    using fn_type = int (*)(int);
-    auto result = f.target<fn_type>();
-    if (!result) {
-        auto r = f(1);
-        return "can't convert to function pointer: eval(1) = " + std::to_string(r);
-    } else if (*result == dummy_function) {
-        auto r = (*result)(1);
-        return "matches dummy_function: eval(1) = " + std::to_string(r);
-    } else {
-        return "argument does NOT match dummy_function. This should never happen!";
-    }
-}
+TEST_SUBMODULE(callbacks, m) {
+    // test_callbacks, test_function_signatures
+    m.def("test_callback1", [](py::object func) { return func(); });
+    m.def("test_callback2", [](py::object func) { return func("Hello", 'x', true, 5); });
+    m.def("test_callback3", [](const std::function<int(int)> &func) {
+        return "func(43) = " + std::to_string(func(43)); });
+    m.def("test_callback4", []() -> std::function<int(int)> { return [](int i) { return i+1; }; });
+    m.def("test_callback5", []() {
+        return py::cpp_function([](int i) { return i+1; }, py::arg("number"));
+    });
 
-struct Payload {
-    Payload() {
-        print_default_created(this);
-    }
-    ~Payload() {
-        print_destroyed(this);
-    }
-    Payload(const Payload &) {
-        print_copy_created(this);
-    }
-    Payload(Payload &&) {
-        print_move_created(this);
-    }
-};
-
-/// Something to trigger a conversion error
-struct Unregistered {};
-
-class AbstractBase {
-public:
-  virtual unsigned int func() = 0;
-};
-
-void func_accepting_func_accepting_base(std::function<double(AbstractBase&)>) { }
-
-struct MovableObject {
-  bool valid = true;
-
-  MovableObject() = default;
-  MovableObject(const MovableObject &) = default;
-  MovableObject &operator=(const MovableObject &) = default;
-  MovableObject(MovableObject &&o) : valid(o.valid) { o.valid = false; }
-  MovableObject &operator=(MovableObject &&o) {
-    valid = o.valid;
-    o.valid = false;
-    return *this;
-  }
-};
-
-test_initializer callbacks([](py::module &m) {
-    m.def("test_callback1", &test_callback1);
-    m.def("test_callback2", &test_callback2);
-    m.def("test_callback3", &test_callback3);
-    m.def("test_callback4", &test_callback4);
-    m.def("test_callback5", &test_callback5);
-
-    // Test keyword args and generalized unpacking
+    // test_keyword_args_and_generalized_unpacking
     m.def("test_tuple_unpacking", [](py::function f) {
         auto t1 = py::make_tuple(2, 3);
         auto t2 = py::make_tuple(5, 6);
@@ -144,13 +67,22 @@ test_initializer callbacks([](py::module &m) {
     });
 
     m.def("test_arg_conversion_error1", [](py::function f) {
-        f(234, Unregistered(), "kw"_a=567);
+        f(234, UnregisteredType(), "kw"_a=567);
     });
 
     m.def("test_arg_conversion_error2", [](py::function f) {
-        f(234, "expected_name"_a=Unregistered(), "kw"_a=567);
+        f(234, "expected_name"_a=UnregisteredType(), "kw"_a=567);
     });
 
+    // test_lambda_closure_cleanup
+    struct Payload {
+        Payload() { print_default_created(this); }
+        ~Payload() { print_destroyed(this); }
+        Payload(const Payload &) { print_copy_created(this); }
+        Payload(Payload &&) { print_move_created(this); }
+    };
+    // Export the payload constructor statistics for testing purposes:
+    m.def("payload_cstats", &ConstructorStats::get<Payload>);
     /* Test cleanup of lambda closure */
     m.def("test_cleanup", []() -> std::function<void(void)> {
         Payload p;
@@ -161,22 +93,57 @@ test_initializer callbacks([](py::module &m) {
         };
     });
 
+    // test_cpp_function_roundtrip
     /* Test if passing a function pointer from C++ -> Python -> C++ yields the original pointer */
     m.def("dummy_function", &dummy_function);
-    m.def("dummy_function2", &dummy_function2);
-    m.def("roundtrip", &roundtrip, py::arg("f"), py::arg("expect_none")=false);
-    m.def("test_dummy_function", &test_dummy_function);
-    // Export the payload constructor statistics for testing purposes:
-    m.def("payload_cstats", &ConstructorStats::get<Payload>);
-
-    m.def("func_accepting_func_accepting_base",
-          func_accepting_func_accepting_base);
+    m.def("dummy_function2", [](int i, int j) { return i + j; });
+    m.def("roundtrip", [](std::function<int(int)> f, bool expect_none = false) {
+        if (expect_none && f)
+            throw std::runtime_error("Expected None to be converted to empty std::function");
+        return f;
+    }, py::arg("f"), py::arg("expect_none")=false);
+    m.def("test_dummy_function", [](const std::function<int(int)> &f) -> std::string {
+        using fn_type = int (*)(int);
+        auto result = f.target<fn_type>();
+        if (!result) {
+            auto r = f(1);
+            return "can't convert to function pointer: eval(1) = " + std::to_string(r);
+        } else if (*result == dummy_function) {
+            auto r = (*result)(1);
+            return "matches dummy_function: eval(1) = " + std::to_string(r);
+        } else {
+            return "argument does NOT match dummy_function. This should never happen!";
+        }
+    });
 
+    class AbstractBase { public: virtual unsigned int func() = 0; };
+    m.def("func_accepting_func_accepting_base", [](std::function<double(AbstractBase&)>) { });
+
+    struct MovableObject {
+        bool valid = true;
+
+        MovableObject() = default;
+        MovableObject(const MovableObject &) = default;
+        MovableObject &operator=(const MovableObject &) = default;
+        MovableObject(MovableObject &&o) : valid(o.valid) { o.valid = false; }
+        MovableObject &operator=(MovableObject &&o) {
+            valid = o.valid;
+            o.valid = false;
+            return *this;
+        }
+    };
     py::class_<MovableObject>(m, "MovableObject");
 
+    // test_movable_object
     m.def("callback_with_movable", [](std::function<void(MovableObject &)> f) {
         auto x = MovableObject();
         f(x); // lvalue reference shouldn't move out object
         return x.valid; // must still return `true`
-      });
-});
+    });
+
+    // test_bound_method_callback
+    struct CppBoundMethodTest {};
+    py::class_<CppBoundMethodTest>(m, "CppBoundMethodTest")
+        .def(py::init<>())
+        .def("triple", [](CppBoundMethodTest &, int val) { return 3 * val; });
+}
diff --git a/ext/pybind11/tests/test_callbacks.py b/ext/pybind11/tests/test_callbacks.py
index f94e7b64c..93c42c22b 100644
--- a/ext/pybind11/tests/test_callbacks.py
+++ b/ext/pybind11/tests/test_callbacks.py
@@ -1,10 +1,9 @@
 import pytest
+from pybind11_tests import callbacks as m
 
 
 def test_callbacks():
     from functools import partial
-    from pybind11_tests import (test_callback1, test_callback2, test_callback3,
-                                test_callback4, test_callback5)
 
     def func1():
         return "func1"
@@ -15,58 +14,65 @@ def test_callbacks():
     def func3(a):
         return "func3({})".format(a)
 
-    assert test_callback1(func1) == "func1"
-    assert test_callback2(func2) == ("func2", "Hello", "x", True, 5)
-    assert test_callback1(partial(func2, 1, 2, 3, 4)) == ("func2", 1, 2, 3, 4)
-    assert test_callback1(partial(func3, "partial")) == "func3(partial)"
-    assert test_callback3(lambda i: i + 1) == "func(43) = 44"
+    assert m.test_callback1(func1) == "func1"
+    assert m.test_callback2(func2) == ("func2", "Hello", "x", True, 5)
+    assert m.test_callback1(partial(func2, 1, 2, 3, 4)) == ("func2", 1, 2, 3, 4)
+    assert m.test_callback1(partial(func3, "partial")) == "func3(partial)"
+    assert m.test_callback3(lambda i: i + 1) == "func(43) = 44"
 
-    f = test_callback4()
+    f = m.test_callback4()
     assert f(43) == 44
-    f = test_callback5()
+    f = m.test_callback5()
     assert f(number=43) == 44
 
 
+def test_bound_method_callback():
+    # Bound Python method:
+    class MyClass:
+        def double(self, val):
+            return 2 * val
+
+    z = MyClass()
+    assert m.test_callback3(z.double) == "func(43) = 86"
+
+    z = m.CppBoundMethodTest()
+    assert m.test_callback3(z.triple) == "func(43) = 129"
+
+
 def test_keyword_args_and_generalized_unpacking():
-    from pybind11_tests import (test_tuple_unpacking, test_dict_unpacking, test_keyword_args,
-                                test_unpacking_and_keywords1, test_unpacking_and_keywords2,
-                                test_unpacking_error1, test_unpacking_error2,
-                                test_arg_conversion_error1, test_arg_conversion_error2)
 
     def f(*args, **kwargs):
         return args, kwargs
 
-    assert test_tuple_unpacking(f) == (("positional", 1, 2, 3, 4, 5, 6), {})
-    assert test_dict_unpacking(f) == (("positional", 1), {"key": "value", "a": 1, "b": 2})
-    assert test_keyword_args(f) == ((), {"x": 10, "y": 20})
-    assert test_unpacking_and_keywords1(f) == ((1, 2), {"c": 3, "d": 4})
-    assert test_unpacking_and_keywords2(f) == (
+    assert m.test_tuple_unpacking(f) == (("positional", 1, 2, 3, 4, 5, 6), {})
+    assert m.test_dict_unpacking(f) == (("positional", 1), {"key": "value", "a": 1, "b": 2})
+    assert m.test_keyword_args(f) == ((), {"x": 10, "y": 20})
+    assert m.test_unpacking_and_keywords1(f) == ((1, 2), {"c": 3, "d": 4})
+    assert m.test_unpacking_and_keywords2(f) == (
         ("positional", 1, 2, 3, 4, 5),
         {"key": "value", "a": 1, "b": 2, "c": 3, "d": 4, "e": 5}
     )
 
     with pytest.raises(TypeError) as excinfo:
-        test_unpacking_error1(f)
+        m.test_unpacking_error1(f)
     assert "Got multiple values for keyword argument" in str(excinfo.value)
 
     with pytest.raises(TypeError) as excinfo:
-        test_unpacking_error2(f)
+        m.test_unpacking_error2(f)
     assert "Got multiple values for keyword argument" in str(excinfo.value)
 
     with pytest.raises(RuntimeError) as excinfo:
-        test_arg_conversion_error1(f)
+        m.test_arg_conversion_error1(f)
     assert "Unable to convert call argument" in str(excinfo.value)
 
     with pytest.raises(RuntimeError) as excinfo:
-        test_arg_conversion_error2(f)
+        m.test_arg_conversion_error2(f)
     assert "Unable to convert call argument" in str(excinfo.value)
 
 
 def test_lambda_closure_cleanup():
-    from pybind11_tests import test_cleanup, payload_cstats
-
-    test_cleanup()
-    cstats = payload_cstats()
+    m.test_cleanup()
+    cstats = m.payload_cstats()
     assert cstats.alive() == 0
     assert cstats.copy_constructions == 1
     assert cstats.move_constructions >= 1
@@ -74,31 +80,28 @@ def test_lambda_closure_cleanup():
 
 def test_cpp_function_roundtrip():
     """Test if passing a function pointer from C++ -> Python -> C++ yields the original pointer"""
-    from pybind11_tests import dummy_function, dummy_function2, test_dummy_function, roundtrip
 
-    assert test_dummy_function(dummy_function) == "matches dummy_function: eval(1) = 2"
-    assert test_dummy_function(roundtrip(dummy_function)) == "matches dummy_function: eval(1) = 2"
-    assert roundtrip(None, expect_none=True) is None
-    assert test_dummy_function(lambda x: x + 2) == "can't convert to function pointer: eval(1) = 3"
+    assert m.test_dummy_function(m.dummy_function) == "matches dummy_function: eval(1) = 2"
+    assert (m.test_dummy_function(m.roundtrip(m.dummy_function)) ==
+            "matches dummy_function: eval(1) = 2")
+    assert m.roundtrip(None, expect_none=True) is None
+    assert (m.test_dummy_function(lambda x: x + 2) ==
+            "can't convert to function pointer: eval(1) = 3")
 
     with pytest.raises(TypeError) as excinfo:
-        test_dummy_function(dummy_function2)
+        m.test_dummy_function(m.dummy_function2)
     assert "incompatible function arguments" in str(excinfo.value)
 
     with pytest.raises(TypeError) as excinfo:
-        test_dummy_function(lambda x, y: x + y)
+        m.test_dummy_function(lambda x, y: x + y)
     assert any(s in str(excinfo.value) for s in ("missing 1 required positional argument",
                                                  "takes exactly 2 arguments"))
 
 
 def test_function_signatures(doc):
-    from pybind11_tests import test_callback3, test_callback4
-
-    assert doc(test_callback3) == "test_callback3(arg0: Callable[[int], int]) -> str"
-    assert doc(test_callback4) == "test_callback4() -> Callable[[int], int]"
+    assert doc(m.test_callback3) == "test_callback3(arg0: Callable[[int], int]) -> str"
+    assert doc(m.test_callback4) == "test_callback4() -> Callable[[int], int]"
 
 
 def test_movable_object():
-    from pybind11_tests import callback_with_movable
-
-    assert callback_with_movable(lambda _: None) is True
+    assert m.callback_with_movable(lambda _: None) is True
diff --git a/ext/pybind11/tests/test_chrono.cpp b/ext/pybind11/tests/test_chrono.cpp
index fcc1b6185..195a93bba 100644
--- a/ext/pybind11/tests/test_chrono.cpp
+++ b/ext/pybind11/tests/test_chrono.cpp
@@ -8,58 +8,40 @@
     BSD-style license that can be found in the LICENSE file.
 */
 
-
 #include "pybind11_tests.h"
-#include "constructor_stats.h"
 #include <pybind11/chrono.h>
 
-// Return the current time off the wall clock
-std::chrono::system_clock::time_point test_chrono1() {
-    return std::chrono::system_clock::now();
-}
+TEST_SUBMODULE(chrono, m) {
+    using system_time = std::chrono::system_clock::time_point;
+    using steady_time = std::chrono::steady_clock::time_point;
+    // test_chrono_system_clock
+    // Return the current time off the wall clock
+    m.def("test_chrono1", []() { return std::chrono::system_clock::now(); });
 
-// Round trip the passed in system clock time
-std::chrono::system_clock::time_point test_chrono2(std::chrono::system_clock::time_point t) {
-    return t;
-}
-
-// Round trip the passed in duration
-std::chrono::system_clock::duration test_chrono3(std::chrono::system_clock::duration d) {
-    return d;
-}
+    // test_chrono_system_clock_roundtrip
+    // Round trip the passed in system clock time
+    m.def("test_chrono2", [](system_time t) { return t; });
 
-// Difference between two passed in time_points
-std::chrono::system_clock::duration test_chrono4(std::chrono::system_clock::time_point a, std::chrono::system_clock::time_point b) {
-    return a - b;
-}
+    // test_chrono_duration_roundtrip
+    // Round trip the passed in duration
+    m.def("test_chrono3", [](std::chrono::system_clock::duration d) { return d; });
 
-// Return the current time off the steady_clock
-std::chrono::steady_clock::time_point test_chrono5() {
-    return std::chrono::steady_clock::now();
-}
+    // test_chrono_duration_subtraction_equivalence
+    // Difference between two passed in time_points
+    m.def("test_chrono4", [](system_time a, system_time b) { return a - b; });
 
-// Round trip a steady clock timepoint
-std::chrono::steady_clock::time_point test_chrono6(std::chrono::steady_clock::time_point t) {
-    return t;
-}
+    // test_chrono_steady_clock
+    // Return the current time off the steady_clock
+    m.def("test_chrono5", []() { return std::chrono::steady_clock::now(); });
 
-// Roundtrip a duration in microseconds from a float argument
-std::chrono::microseconds test_chrono7(std::chrono::microseconds t) {
-    return t;
-}
+    // test_chrono_steady_clock_roundtrip
+    // Round trip a steady clock timepoint
+    m.def("test_chrono6", [](steady_time t) { return t; });
 
-// Float durations (issue #719)
-std::chrono::duration<double> test_chrono_float_diff(std::chrono::duration<float> a, std::chrono::duration<float> b) {
-    return a - b;
+    // test_floating_point_duration
+    // Roundtrip a duration in microseconds from a float argument
+    m.def("test_chrono7", [](std::chrono::microseconds t) { return t; });
+    // Float durations (issue #719)
+    m.def("test_chrono_float_diff", [](std::chrono::duration<float> a, std::chrono::duration<float> b) {
+        return a - b; });
 }
-
-test_initializer chrono([] (py::module &m) {
-    m.def("test_chrono1", &test_chrono1);
-    m.def("test_chrono2", &test_chrono2);
-    m.def("test_chrono3", &test_chrono3);
-    m.def("test_chrono4", &test_chrono4);
-    m.def("test_chrono5", &test_chrono5);
-    m.def("test_chrono6", &test_chrono6);
-    m.def("test_chrono7", &test_chrono7);
-    m.def("test_chrono_float_diff", &test_chrono_float_diff);
-});
diff --git a/ext/pybind11/tests/test_chrono.py b/ext/pybind11/tests/test_chrono.py
index 55094edbf..2b75bd191 100644
--- a/ext/pybind11/tests/test_chrono.py
+++ b/ext/pybind11/tests/test_chrono.py
@@ -1,11 +1,11 @@
+from pybind11_tests import chrono as m
+import datetime
 
 
 def test_chrono_system_clock():
-    from pybind11_tests import test_chrono1
-    import datetime
 
     # Get the time from both c++ and datetime
-    date1 = test_chrono1()
+    date1 = m.test_chrono1()
     date2 = datetime.datetime.today()
 
     # The returned value should be a datetime
@@ -25,13 +25,10 @@ def test_chrono_system_clock():
 
 
 def test_chrono_system_clock_roundtrip():
-    from pybind11_tests import test_chrono2
-    import datetime
-
     date1 = datetime.datetime.today()
 
     # Roundtrip the time
-    date2 = test_chrono2(date1)
+    date2 = m.test_chrono2(date1)
 
     # The returned value should be a datetime
     assert isinstance(date2, datetime.datetime)
@@ -44,8 +41,6 @@ def test_chrono_system_clock_roundtrip():
 
 
 def test_chrono_duration_roundtrip():
-    from pybind11_tests import test_chrono3
-    import datetime
 
     # Get the difference between two times (a timedelta)
     date1 = datetime.datetime.today()
@@ -55,7 +50,7 @@ def test_chrono_duration_roundtrip():
     # Make sure this is a timedelta
     assert isinstance(diff, datetime.timedelta)
 
-    cpp_diff = test_chrono3(diff)
+    cpp_diff = m.test_chrono3(diff)
 
     assert cpp_diff.days == diff.days
     assert cpp_diff.seconds == diff.seconds
@@ -63,14 +58,12 @@ def test_chrono_duration_roundtrip():
 
 
 def test_chrono_duration_subtraction_equivalence():
-    from pybind11_tests import test_chrono4
-    import datetime
 
     date1 = datetime.datetime.today()
     date2 = datetime.datetime.today()
 
     diff = date2 - date1
-    cpp_diff = test_chrono4(date2, date1)
+    cpp_diff = m.test_chrono4(date2, date1)
 
     assert cpp_diff.days == diff.days
     assert cpp_diff.seconds == diff.seconds
@@ -78,22 +71,13 @@ def test_chrono_duration_subtraction_equivalence():
 
 
 def test_chrono_steady_clock():
-    from pybind11_tests import test_chrono5
-    import datetime
-
-    time1 = test_chrono5()
-    time2 = test_chrono5()
-
+    time1 = m.test_chrono5()
     assert isinstance(time1, datetime.timedelta)
-    assert isinstance(time2, datetime.timedelta)
 
 
 def test_chrono_steady_clock_roundtrip():
-    from pybind11_tests import test_chrono6
-    import datetime
-
     time1 = datetime.timedelta(days=10, seconds=10, microseconds=100)
-    time2 = test_chrono6(time1)
+    time2 = m.test_chrono6(time1)
 
     assert isinstance(time2, datetime.timedelta)
 
@@ -104,17 +88,14 @@ def test_chrono_steady_clock_roundtrip():
 
 
 def test_floating_point_duration():
-    from pybind11_tests import test_chrono7, test_chrono_float_diff
-    import datetime
-
-    # Test using 35.525123 seconds as an example floating point number in seconds
-    time = test_chrono7(35.525123)
+    # Test using a floating point number in seconds
+    time = m.test_chrono7(35.525123)
 
     assert isinstance(time, datetime.timedelta)
 
     assert time.seconds == 35
     assert 525122 <= time.microseconds <= 525123
 
-    diff = test_chrono_float_diff(43.789012, 1.123456)
+    diff = m.test_chrono_float_diff(43.789012, 1.123456)
     assert diff.seconds == 42
     assert 665556 <= diff.microseconds <= 665557
diff --git a/ext/pybind11/tests/test_class.cpp b/ext/pybind11/tests/test_class.cpp
new file mode 100644
index 000000000..222190617
--- /dev/null
+++ b/ext/pybind11/tests/test_class.cpp
@@ -0,0 +1,357 @@
+/*
+    tests/test_class.cpp -- test py::class_ definitions and basic functionality
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include "constructor_stats.h"
+#include "local_bindings.h"
+
+TEST_SUBMODULE(class_, m) {
+    // test_instance
+    struct NoConstructor {
+        static NoConstructor *new_instance() {
+            auto *ptr = new NoConstructor();
+            print_created(ptr, "via new_instance");
+            return ptr;
+        }
+        ~NoConstructor() { print_destroyed(this); }
+    };
+
+    py::class_<NoConstructor>(m, "NoConstructor")
+        .def_static("new_instance", &NoConstructor::new_instance, "Return an instance");
+
+    // test_inheritance
+    class Pet {
+    public:
+        Pet(const std::string &name, const std::string &species)
+            : m_name(name), m_species(species) {}
+        std::string name() const { return m_name; }
+        std::string species() const { return m_species; }
+    private:
+        std::string m_name;
+        std::string m_species;
+    };
+
+    class Dog : public Pet {
+    public:
+        Dog(const std::string &name) : Pet(name, "dog") {}
+        std::string bark() const { return "Woof!"; }
+    };
+
+    class Rabbit : public Pet {
+    public:
+        Rabbit(const std::string &name) : Pet(name, "parrot") {}
+    };
+
+    class Hamster : public Pet {
+    public:
+        Hamster(const std::string &name) : Pet(name, "rodent") {}
+    };
+
+    class Chimera : public Pet {
+        Chimera() : Pet("Kimmy", "chimera") {}
+    };
+
+    py::class_<Pet> pet_class(m, "Pet");
+    pet_class
+        .def(py::init<std::string, std::string>())
+        .def("name", &Pet::name)
+        .def("species", &Pet::species);
+
+    /* One way of declaring a subclass relationship: reference parent's class_ object */
+    py::class_<Dog>(m, "Dog", pet_class)
+        .def(py::init<std::string>());
+
+    /* Another way of declaring a subclass relationship: reference parent's C++ type */
+    py::class_<Rabbit, Pet>(m, "Rabbit")
+        .def(py::init<std::string>());
+
+    /* And another: list parent in class template arguments */
+    py::class_<Hamster, Pet>(m, "Hamster")
+        .def(py::init<std::string>());
+
+    /* Constructors are not inherited by default */
+    py::class_<Chimera, Pet>(m, "Chimera");
+
+    m.def("pet_name_species", [](const Pet &pet) { return pet.name() + " is a " + pet.species(); });
+    m.def("dog_bark", [](const Dog &dog) { return dog.bark(); });
+
+    // test_automatic_upcasting
+    struct BaseClass { virtual ~BaseClass() {} };
+    struct DerivedClass1 : BaseClass { };
+    struct DerivedClass2 : BaseClass { };
+
+    py::class_<BaseClass>(m, "BaseClass").def(py::init<>());
+    py::class_<DerivedClass1>(m, "DerivedClass1").def(py::init<>());
+    py::class_<DerivedClass2>(m, "DerivedClass2").def(py::init<>());
+
+    m.def("return_class_1", []() -> BaseClass* { return new DerivedClass1(); });
+    m.def("return_class_2", []() -> BaseClass* { return new DerivedClass2(); });
+    m.def("return_class_n", [](int n) -> BaseClass* {
+        if (n == 1) return new DerivedClass1();
+        if (n == 2) return new DerivedClass2();
+        return new BaseClass();
+    });
+    m.def("return_none", []() -> BaseClass* { return nullptr; });
+
+    // test_isinstance
+    m.def("check_instances", [](py::list l) {
+        return py::make_tuple(
+            py::isinstance<py::tuple>(l[0]),
+            py::isinstance<py::dict>(l[1]),
+            py::isinstance<Pet>(l[2]),
+            py::isinstance<Pet>(l[3]),
+            py::isinstance<Dog>(l[4]),
+            py::isinstance<Rabbit>(l[5]),
+            py::isinstance<UnregisteredType>(l[6])
+        );
+    });
+
+    // test_mismatched_holder
+    struct MismatchBase1 { };
+    struct MismatchDerived1 : MismatchBase1 { };
+
+    struct MismatchBase2 { };
+    struct MismatchDerived2 : MismatchBase2 { };
+
+    m.def("mismatched_holder_1", []() {
+        auto mod = py::module::import("__main__");
+        py::class_<MismatchBase1, std::shared_ptr<MismatchBase1>>(mod, "MismatchBase1");
+        py::class_<MismatchDerived1, MismatchBase1>(mod, "MismatchDerived1");
+    });
+    m.def("mismatched_holder_2", []() {
+        auto mod = py::module::import("__main__");
+        py::class_<MismatchBase2>(mod, "MismatchBase2");
+        py::class_<MismatchDerived2, std::shared_ptr<MismatchDerived2>,
+                   MismatchBase2>(mod, "MismatchDerived2");
+    });
+
+    // test_override_static
+    // #511: problem with inheritance + overwritten def_static
+    struct MyBase {
+        static std::unique_ptr<MyBase> make() {
+            return std::unique_ptr<MyBase>(new MyBase());
+        }
+    };
+
+    struct MyDerived : MyBase {
+        static std::unique_ptr<MyDerived> make() {
+            return std::unique_ptr<MyDerived>(new MyDerived());
+        }
+    };
+
+    py::class_<MyBase>(m, "MyBase")
+        .def_static("make", &MyBase::make);
+
+    py::class_<MyDerived, MyBase>(m, "MyDerived")
+        .def_static("make", &MyDerived::make)
+        .def_static("make2", &MyDerived::make);
+
+    // test_implicit_conversion_life_support
+    struct ConvertibleFromUserType {
+        int i;
+
+        ConvertibleFromUserType(UserType u) : i(u.value()) { }
+    };
+
+    py::class_<ConvertibleFromUserType>(m, "AcceptsUserType")
+        .def(py::init<UserType>());
+    py::implicitly_convertible<UserType, ConvertibleFromUserType>();
+
+    m.def("implicitly_convert_argument", [](const ConvertibleFromUserType &r) { return r.i; });
+    m.def("implicitly_convert_variable", [](py::object o) {
+        // `o` is `UserType` and `r` is a reference to a temporary created by implicit
+        // conversion. This is valid when called inside a bound function because the temp
+        // object is attached to the same life support system as the arguments.
+        const auto &r = o.cast<const ConvertibleFromUserType &>();
+        return r.i;
+    });
+    m.add_object("implicitly_convert_variable_fail", [&] {
+        auto f = [](PyObject *, PyObject *args) -> PyObject * {
+            auto o = py::reinterpret_borrow<py::tuple>(args)[0];
+            try { // It should fail here because there is no life support.
+                o.cast<const ConvertibleFromUserType &>();
+            } catch (const py::cast_error &e) {
+                return py::str(e.what()).release().ptr();
+            }
+            return py::str().release().ptr();
+        };
+
+        auto def = new PyMethodDef{"f", f, METH_VARARGS, nullptr};
+        return py::reinterpret_steal<py::object>(PyCFunction_NewEx(def, nullptr, m.ptr()));
+    }());
+
+    // test_operator_new_delete
+    struct HasOpNewDel {
+        std::uint64_t i;
+        static void *operator new(size_t s) { py::print("A new", s); return ::operator new(s); }
+        static void *operator new(size_t s, void *ptr) { py::print("A placement-new", s); return ptr; }
+        static void operator delete(void *p) { py::print("A delete"); return ::operator delete(p); }
+    };
+    struct HasOpNewDelSize {
+        std::uint32_t i;
+        static void *operator new(size_t s) { py::print("B new", s); return ::operator new(s); }
+        static void *operator new(size_t s, void *ptr) { py::print("B placement-new", s); return ptr; }
+        static void operator delete(void *p, size_t s) { py::print("B delete", s); return ::operator delete(p); }
+    };
+    struct AliasedHasOpNewDelSize {
+        std::uint64_t i;
+        static void *operator new(size_t s) { py::print("C new", s); return ::operator new(s); }
+        static void *operator new(size_t s, void *ptr) { py::print("C placement-new", s); return ptr; }
+        static void operator delete(void *p, size_t s) { py::print("C delete", s); return ::operator delete(p); }
+        virtual ~AliasedHasOpNewDelSize() = default;
+    };
+    struct PyAliasedHasOpNewDelSize : AliasedHasOpNewDelSize {
+        PyAliasedHasOpNewDelSize() = default;
+        PyAliasedHasOpNewDelSize(int) { }
+        std::uint64_t j;
+    };
+    struct HasOpNewDelBoth {
+        std::uint32_t i[8];
+        static void *operator new(size_t s) { py::print("D new", s); return ::operator new(s); }
+        static void *operator new(size_t s, void *ptr) { py::print("D placement-new", s); return ptr; }
+        static void operator delete(void *p) { py::print("D delete"); return ::operator delete(p); }
+        static void operator delete(void *p, size_t s) { py::print("D wrong delete", s); return ::operator delete(p); }
+    };
+    py::class_<HasOpNewDel>(m, "HasOpNewDel").def(py::init<>());
+    py::class_<HasOpNewDelSize>(m, "HasOpNewDelSize").def(py::init<>());
+    py::class_<HasOpNewDelBoth>(m, "HasOpNewDelBoth").def(py::init<>());
+    py::class_<AliasedHasOpNewDelSize, PyAliasedHasOpNewDelSize> aliased(m, "AliasedHasOpNewDelSize");
+    aliased.def(py::init<>());
+    aliased.attr("size_noalias") = py::int_(sizeof(AliasedHasOpNewDelSize));
+    aliased.attr("size_alias") = py::int_(sizeof(PyAliasedHasOpNewDelSize));
+
+    // This test is actually part of test_local_bindings (test_duplicate_local), but we need a
+    // definition in a different compilation unit within the same module:
+    bind_local<LocalExternal, 17>(m, "LocalExternal", py::module_local());
+
+    // test_bind_protected_functions
+    class ProtectedA {
+    protected:
+        int foo() const { return value; }
+
+    private:
+        int value = 42;
+    };
+
+    class PublicistA : public ProtectedA {
+    public:
+        using ProtectedA::foo;
+    };
+
+    py::class_<ProtectedA>(m, "ProtectedA")
+        .def(py::init<>())
+#if !defined(_MSC_VER) || _MSC_VER >= 1910
+        .def("foo", &PublicistA::foo);
+#else
+        .def("foo", static_cast<int (ProtectedA::*)() const>(&PublicistA::foo));
+#endif
+
+    class ProtectedB {
+    public:
+        virtual ~ProtectedB() = default;
+
+    protected:
+        virtual int foo() const { return value; }
+
+    private:
+        int value = 42;
+    };
+
+    class TrampolineB : public ProtectedB {
+    public:
+        int foo() const override { PYBIND11_OVERLOAD(int, ProtectedB, foo, ); }
+    };
+
+    class PublicistB : public ProtectedB {
+    public:
+        using ProtectedB::foo;
+    };
+
+    py::class_<ProtectedB, TrampolineB>(m, "ProtectedB")
+        .def(py::init<>())
+#if !defined(_MSC_VER) || _MSC_VER >= 1910
+        .def("foo", &PublicistB::foo);
+#else
+        .def("foo", static_cast<int (ProtectedB::*)() const>(&PublicistB::foo));
+#endif
+
+    // test_brace_initialization
+    struct BraceInitialization {
+        int field1;
+        std::string field2;
+    };
+
+    py::class_<BraceInitialization>(m, "BraceInitialization")
+        .def(py::init<int, const std::string &>())
+        .def_readwrite("field1", &BraceInitialization::field1)
+        .def_readwrite("field2", &BraceInitialization::field2);
+
+    // test_reentrant_implicit_conversion_failure
+    // #1035: issue with runaway reentrant implicit conversion
+    struct BogusImplicitConversion {
+        BogusImplicitConversion(const BogusImplicitConversion &) { }
+    };
+
+    py::class_<BogusImplicitConversion>(m, "BogusImplicitConversion")
+        .def(py::init<const BogusImplicitConversion &>());
+
+    py::implicitly_convertible<int, BogusImplicitConversion>();
+}
+
+template <int N> class BreaksBase { public: virtual ~BreaksBase() = default; };
+template <int N> class BreaksTramp : public BreaksBase<N> {};
+// These should all compile just fine:
+typedef py::class_<BreaksBase<1>, std::unique_ptr<BreaksBase<1>>, BreaksTramp<1>> DoesntBreak1;
+typedef py::class_<BreaksBase<2>, BreaksTramp<2>, std::unique_ptr<BreaksBase<2>>> DoesntBreak2;
+typedef py::class_<BreaksBase<3>, std::unique_ptr<BreaksBase<3>>> DoesntBreak3;
+typedef py::class_<BreaksBase<4>, BreaksTramp<4>> DoesntBreak4;
+typedef py::class_<BreaksBase<5>> DoesntBreak5;
+typedef py::class_<BreaksBase<6>, std::shared_ptr<BreaksBase<6>>, BreaksTramp<6>> DoesntBreak6;
+typedef py::class_<BreaksBase<7>, BreaksTramp<7>, std::shared_ptr<BreaksBase<7>>> DoesntBreak7;
+typedef py::class_<BreaksBase<8>, std::shared_ptr<BreaksBase<8>>> DoesntBreak8;
+#define CHECK_BASE(N) static_assert(std::is_same<typename DoesntBreak##N::type, BreaksBase<N>>::value, \
+        "DoesntBreak" #N " has wrong type!")
+CHECK_BASE(1); CHECK_BASE(2); CHECK_BASE(3); CHECK_BASE(4); CHECK_BASE(5); CHECK_BASE(6); CHECK_BASE(7); CHECK_BASE(8);
+#define CHECK_ALIAS(N) static_assert(DoesntBreak##N::has_alias && std::is_same<typename DoesntBreak##N::type_alias, BreaksTramp<N>>::value, \
+        "DoesntBreak" #N " has wrong type_alias!")
+#define CHECK_NOALIAS(N) static_assert(!DoesntBreak##N::has_alias && std::is_void<typename DoesntBreak##N::type_alias>::value, \
+        "DoesntBreak" #N " has type alias, but shouldn't!")
+CHECK_ALIAS(1); CHECK_ALIAS(2); CHECK_NOALIAS(3); CHECK_ALIAS(4); CHECK_NOALIAS(5); CHECK_ALIAS(6); CHECK_ALIAS(7); CHECK_NOALIAS(8);
+#define CHECK_HOLDER(N, TYPE) static_assert(std::is_same<typename DoesntBreak##N::holder_type, std::TYPE##_ptr<BreaksBase<N>>>::value, \
+        "DoesntBreak" #N " has wrong holder_type!")
+CHECK_HOLDER(1, unique); CHECK_HOLDER(2, unique); CHECK_HOLDER(3, unique); CHECK_HOLDER(4, unique); CHECK_HOLDER(5, unique);
+CHECK_HOLDER(6, shared); CHECK_HOLDER(7, shared); CHECK_HOLDER(8, shared);
+
+// There's no nice way to test that these fail because they fail to compile; leave them here,
+// though, so that they can be manually tested by uncommenting them (and seeing that compilation
+// failures occurs).
+
+// We have to actually look into the type: the typedef alone isn't enough to instantiate the type:
+#define CHECK_BROKEN(N) static_assert(std::is_same<typename Breaks##N::type, BreaksBase<-N>>::value, \
+        "Breaks1 has wrong type!");
+
+//// Two holder classes:
+//typedef py::class_<BreaksBase<-1>, std::unique_ptr<BreaksBase<-1>>, std::unique_ptr<BreaksBase<-1>>> Breaks1;
+//CHECK_BROKEN(1);
+//// Two aliases:
+//typedef py::class_<BreaksBase<-2>, BreaksTramp<-2>, BreaksTramp<-2>> Breaks2;
+//CHECK_BROKEN(2);
+//// Holder + 2 aliases
+//typedef py::class_<BreaksBase<-3>, std::unique_ptr<BreaksBase<-3>>, BreaksTramp<-3>, BreaksTramp<-3>> Breaks3;
+//CHECK_BROKEN(3);
+//// Alias + 2 holders
+//typedef py::class_<BreaksBase<-4>, std::unique_ptr<BreaksBase<-4>>, BreaksTramp<-4>, std::shared_ptr<BreaksBase<-4>>> Breaks4;
+//CHECK_BROKEN(4);
+//// Invalid option (not a subclass or holder)
+//typedef py::class_<BreaksBase<-5>, BreaksTramp<-4>> Breaks5;
+//CHECK_BROKEN(5);
+//// Invalid option: multiple inheritance not supported:
+//template <> struct BreaksBase<-8> : BreaksBase<-6>, BreaksBase<-7> {};
+//typedef py::class_<BreaksBase<-8>, BreaksBase<-6>, BreaksBase<-7>> Breaks8;
+//CHECK_BROKEN(8);
diff --git a/ext/pybind11/tests/test_class.py b/ext/pybind11/tests/test_class.py
new file mode 100644
index 000000000..412d6798e
--- /dev/null
+++ b/ext/pybind11/tests/test_class.py
@@ -0,0 +1,235 @@
+import pytest
+
+from pybind11_tests import class_ as m
+from pybind11_tests import UserType, ConstructorStats
+
+
+def test_repr():
+    # In Python 3.3+, repr() accesses __qualname__
+    assert "pybind11_type" in repr(type(UserType))
+    assert "UserType" in repr(UserType)
+
+
+def test_instance(msg):
+    with pytest.raises(TypeError) as excinfo:
+        m.NoConstructor()
+    assert msg(excinfo.value) == "m.class_.NoConstructor: No constructor defined!"
+
+    instance = m.NoConstructor.new_instance()
+
+    cstats = ConstructorStats.get(m.NoConstructor)
+    assert cstats.alive() == 1
+    del instance
+    assert cstats.alive() == 0
+
+
+def test_docstrings(doc):
+    assert doc(UserType) == "A `py::class_` type for testing"
+    assert UserType.__name__ == "UserType"
+    assert UserType.__module__ == "pybind11_tests"
+    assert UserType.get_value.__name__ == "get_value"
+    assert UserType.get_value.__module__ == "pybind11_tests"
+
+    assert doc(UserType.get_value) == """
+        get_value(self: m.UserType) -> int
+
+        Get value using a method
+    """
+    assert doc(UserType.value) == "Get/set value using a property"
+
+    assert doc(m.NoConstructor.new_instance) == """
+        new_instance() -> m.class_.NoConstructor
+
+        Return an instance
+    """
+
+
+def test_inheritance(msg):
+    roger = m.Rabbit('Rabbit')
+    assert roger.name() + " is a " + roger.species() == "Rabbit is a parrot"
+    assert m.pet_name_species(roger) == "Rabbit is a parrot"
+
+    polly = m.Pet('Polly', 'parrot')
+    assert polly.name() + " is a " + polly.species() == "Polly is a parrot"
+    assert m.pet_name_species(polly) == "Polly is a parrot"
+
+    molly = m.Dog('Molly')
+    assert molly.name() + " is a " + molly.species() == "Molly is a dog"
+    assert m.pet_name_species(molly) == "Molly is a dog"
+
+    fred = m.Hamster('Fred')
+    assert fred.name() + " is a " + fred.species() == "Fred is a rodent"
+
+    assert m.dog_bark(molly) == "Woof!"
+
+    with pytest.raises(TypeError) as excinfo:
+        m.dog_bark(polly)
+    assert msg(excinfo.value) == """
+        dog_bark(): incompatible function arguments. The following argument types are supported:
+            1. (arg0: m.class_.Dog) -> str
+
+        Invoked with: <m.class_.Pet object at 0>
+    """
+
+    with pytest.raises(TypeError) as excinfo:
+        m.Chimera("lion", "goat")
+    assert "No constructor defined!" in str(excinfo.value)
+
+
+def test_automatic_upcasting():
+    assert type(m.return_class_1()).__name__ == "DerivedClass1"
+    assert type(m.return_class_2()).__name__ == "DerivedClass2"
+    assert type(m.return_none()).__name__ == "NoneType"
+    # Repeat these a few times in a random order to ensure no invalid caching is applied
+    assert type(m.return_class_n(1)).__name__ == "DerivedClass1"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(0)).__name__ == "BaseClass"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(0)).__name__ == "BaseClass"
+    assert type(m.return_class_n(1)).__name__ == "DerivedClass1"
+
+
+def test_isinstance():
+    objects = [tuple(), dict(), m.Pet("Polly", "parrot")] + [m.Dog("Molly")] * 4
+    expected = (True, True, True, True, True, False, False)
+    assert m.check_instances(objects) == expected
+
+
+def test_mismatched_holder():
+    import re
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.mismatched_holder_1()
+    assert re.match('generic_type: type ".*MismatchDerived1" does not have a non-default '
+                    'holder type while its base ".*MismatchBase1" does', str(excinfo.value))
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.mismatched_holder_2()
+    assert re.match('generic_type: type ".*MismatchDerived2" has a non-default holder type '
+                    'while its base ".*MismatchBase2" does not', str(excinfo.value))
+
+
+def test_override_static():
+    """#511: problem with inheritance + overwritten def_static"""
+    b = m.MyBase.make()
+    d1 = m.MyDerived.make2()
+    d2 = m.MyDerived.make()
+
+    assert isinstance(b, m.MyBase)
+    assert isinstance(d1, m.MyDerived)
+    assert isinstance(d2, m.MyDerived)
+
+
+def test_implicit_conversion_life_support():
+    """Ensure the lifetime of temporary objects created for implicit conversions"""
+    assert m.implicitly_convert_argument(UserType(5)) == 5
+    assert m.implicitly_convert_variable(UserType(5)) == 5
+
+    assert "outside a bound function" in m.implicitly_convert_variable_fail(UserType(5))
+
+
+def test_operator_new_delete(capture):
+    """Tests that class-specific operator new/delete functions are invoked"""
+
+    class SubAliased(m.AliasedHasOpNewDelSize):
+        pass
+
+    with capture:
+        a = m.HasOpNewDel()
+        b = m.HasOpNewDelSize()
+        d = m.HasOpNewDelBoth()
+    assert capture == """
+        A new 8
+        B new 4
+        D new 32
+    """
+    sz_alias = str(m.AliasedHasOpNewDelSize.size_alias)
+    sz_noalias = str(m.AliasedHasOpNewDelSize.size_noalias)
+    with capture:
+        c = m.AliasedHasOpNewDelSize()
+        c2 = SubAliased()
+    assert capture == (
+        "C new " + sz_noalias + "\n" +
+        "C new " + sz_alias + "\n"
+    )
+
+    with capture:
+        del a
+        pytest.gc_collect()
+        del b
+        pytest.gc_collect()
+        del d
+        pytest.gc_collect()
+    assert capture == """
+        A delete
+        B delete 4
+        D delete
+    """
+
+    with capture:
+        del c
+        pytest.gc_collect()
+        del c2
+        pytest.gc_collect()
+    assert capture == (
+        "C delete " + sz_noalias + "\n" +
+        "C delete " + sz_alias + "\n"
+    )
+
+
+def test_bind_protected_functions():
+    """Expose protected member functions to Python using a helper class"""
+    a = m.ProtectedA()
+    assert a.foo() == 42
+
+    b = m.ProtectedB()
+    assert b.foo() == 42
+
+    class C(m.ProtectedB):
+        def __init__(self):
+            m.ProtectedB.__init__(self)
+
+        def foo(self):
+            return 0
+
+    c = C()
+    assert c.foo() == 0
+
+
+def test_brace_initialization():
+    """ Tests that simple POD classes can be constructed using C++11 brace initialization """
+    a = m.BraceInitialization(123, "test")
+    assert a.field1 == 123
+    assert a.field2 == "test"
+
+
+@pytest.unsupported_on_pypy
+def test_class_refcount():
+    """Instances must correctly increase/decrease the reference count of their types (#1029)"""
+    from sys import getrefcount
+
+    class PyDog(m.Dog):
+        pass
+
+    for cls in m.Dog, PyDog:
+        refcount_1 = getrefcount(cls)
+        molly = [cls("Molly") for _ in range(10)]
+        refcount_2 = getrefcount(cls)
+
+        del molly
+        pytest.gc_collect()
+        refcount_3 = getrefcount(cls)
+
+        assert refcount_1 == refcount_3
+        assert refcount_2 > refcount_1
+
+
+def test_reentrant_implicit_conversion_failure(msg):
+    # ensure that there is no runaway reentrant implicit conversion (#1035)
+    with pytest.raises(TypeError) as excinfo:
+        m.BogusImplicitConversion(0)
+    assert msg(excinfo.value) == '''__init__(): incompatible constructor arguments. The following argument types are supported:
+    1. m.class_.BogusImplicitConversion(arg0: m.class_.BogusImplicitConversion)
+
+Invoked with: 0'''
diff --git a/ext/pybind11/tests/test_class_args.cpp b/ext/pybind11/tests/test_class_args.cpp
deleted file mode 100644
index e18b39db2..000000000
--- a/ext/pybind11/tests/test_class_args.cpp
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
-    tests/test_class_args.cpp -- tests that various way of defining a class work
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-
-template <int N> class BreaksBase {};
-template <int N> class BreaksTramp : public BreaksBase<N> {};
-// These should all compile just fine:
-typedef py::class_<BreaksBase<1>, std::unique_ptr<BreaksBase<1>>, BreaksTramp<1>> DoesntBreak1;
-typedef py::class_<BreaksBase<2>, BreaksTramp<2>, std::unique_ptr<BreaksBase<2>>> DoesntBreak2;
-typedef py::class_<BreaksBase<3>, std::unique_ptr<BreaksBase<3>>> DoesntBreak3;
-typedef py::class_<BreaksBase<4>, BreaksTramp<4>> DoesntBreak4;
-typedef py::class_<BreaksBase<5>> DoesntBreak5;
-typedef py::class_<BreaksBase<6>, std::shared_ptr<BreaksBase<6>>, BreaksTramp<6>> DoesntBreak6;
-typedef py::class_<BreaksBase<7>, BreaksTramp<7>, std::shared_ptr<BreaksBase<7>>> DoesntBreak7;
-typedef py::class_<BreaksBase<8>, std::shared_ptr<BreaksBase<8>>> DoesntBreak8;
-#define CHECK_BASE(N) static_assert(std::is_same<typename DoesntBreak##N::type, BreaksBase<N>>::value, \
-        "DoesntBreak" #N " has wrong type!")
-CHECK_BASE(1); CHECK_BASE(2); CHECK_BASE(3); CHECK_BASE(4); CHECK_BASE(5); CHECK_BASE(6); CHECK_BASE(7); CHECK_BASE(8);
-#define CHECK_ALIAS(N) static_assert(DoesntBreak##N::has_alias && std::is_same<typename DoesntBreak##N::type_alias, BreaksTramp<N>>::value, \
-        "DoesntBreak" #N " has wrong type_alias!")
-#define CHECK_NOALIAS(N) static_assert(!DoesntBreak##N::has_alias && std::is_void<typename DoesntBreak##N::type_alias>::value, \
-        "DoesntBreak" #N " has type alias, but shouldn't!")
-CHECK_ALIAS(1); CHECK_ALIAS(2); CHECK_NOALIAS(3); CHECK_ALIAS(4); CHECK_NOALIAS(5); CHECK_ALIAS(6); CHECK_ALIAS(7); CHECK_NOALIAS(8);
-#define CHECK_HOLDER(N, TYPE) static_assert(std::is_same<typename DoesntBreak##N::holder_type, std::TYPE##_ptr<BreaksBase<N>>>::value, \
-        "DoesntBreak" #N " has wrong holder_type!")
-CHECK_HOLDER(1, unique); CHECK_HOLDER(2, unique); CHECK_HOLDER(3, unique); CHECK_HOLDER(4, unique); CHECK_HOLDER(5, unique);
-CHECK_HOLDER(6, shared); CHECK_HOLDER(7, shared); CHECK_HOLDER(8, shared);
-
-// There's no nice way to test that these fail because they fail to compile; leave them here,
-// though, so that they can be manually tested by uncommenting them (and seeing that compilation
-// failures occurs).
-
-// We have to actually look into the type: the typedef alone isn't enough to instantiate the type:
-#define CHECK_BROKEN(N) static_assert(std::is_same<typename Breaks##N::type, BreaksBase<-N>>::value, \
-        "Breaks1 has wrong type!");
-
-//// Two holder classes:
-//typedef py::class_<BreaksBase<-1>, std::unique_ptr<BreaksBase<-1>>, std::unique_ptr<BreaksBase<-1>>> Breaks1;
-//CHECK_BROKEN(1);
-//// Two aliases:
-//typedef py::class_<BreaksBase<-2>, BreaksTramp<-2>, BreaksTramp<-2>> Breaks2;
-//CHECK_BROKEN(2);
-//// Holder + 2 aliases
-//typedef py::class_<BreaksBase<-3>, std::unique_ptr<BreaksBase<-3>>, BreaksTramp<-3>, BreaksTramp<-3>> Breaks3;
-//CHECK_BROKEN(3);
-//// Alias + 2 holders
-//typedef py::class_<BreaksBase<-4>, std::unique_ptr<BreaksBase<-4>>, BreaksTramp<-4>, std::shared_ptr<BreaksBase<-4>>> Breaks4;
-//CHECK_BROKEN(4);
-//// Invalid option (not a subclass or holder)
-//typedef py::class_<BreaksBase<-5>, BreaksTramp<-4>> Breaks5;
-//CHECK_BROKEN(5);
-//// Invalid option: multiple inheritance not supported:
-//template <> struct BreaksBase<-8> : BreaksBase<-6>, BreaksBase<-7> {};
-//typedef py::class_<BreaksBase<-8>, BreaksBase<-6>, BreaksBase<-7>> Breaks8;
-//CHECK_BROKEN(8);
-
-test_initializer class_args([](py::module &m) {
-    // Just test that this compiled okay
-    m.def("class_args_noop", []() {});
-});
diff --git a/ext/pybind11/tests/test_class_args.py b/ext/pybind11/tests/test_class_args.py
deleted file mode 100644
index 40cbcec9f..000000000
--- a/ext/pybind11/tests/test_class_args.py
+++ /dev/null
@@ -1,8 +0,0 @@
-
-
-def test_class_args():
-    """There's basically nothing to test here; just make sure the code compiled
-    and declared its definition
-    """
-    from pybind11_tests import class_args_noop
-    class_args_noop()
diff --git a/ext/pybind11/tests/test_cmake_build/CMakeLists.txt b/ext/pybind11/tests/test_cmake_build/CMakeLists.txt
new file mode 100644
index 000000000..c9b5fcb2e
--- /dev/null
+++ b/ext/pybind11/tests/test_cmake_build/CMakeLists.txt
@@ -0,0 +1,58 @@
+add_custom_target(test_cmake_build)
+
+if(CMAKE_VERSION VERSION_LESS 3.1)
+  # 3.0 needed for interface library for subdirectory_target/installed_target
+  # 3.1 needed for cmake -E env for testing
+  return()
+endif()
+
+include(CMakeParseArguments)
+function(pybind11_add_build_test name)
+  cmake_parse_arguments(ARG "INSTALL" "" "" ${ARGN})
+
+  set(build_options "-DCMAKE_PREFIX_PATH=${PROJECT_BINARY_DIR}/mock_install"
+                    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+                    "-DPYTHON_EXECUTABLE:FILEPATH=${PYTHON_EXECUTABLE}"
+                    "-DPYBIND11_CPP_STANDARD=${PYBIND11_CPP_STANDARD}")
+  if(NOT ARG_INSTALL)
+    list(APPEND build_options "-DPYBIND11_PROJECT_DIR=${PROJECT_SOURCE_DIR}")
+  endif()
+
+  add_custom_target(test_${name} ${CMAKE_CTEST_COMMAND}
+    --quiet --output-log ${name}.log
+    --build-and-test "${CMAKE_CURRENT_SOURCE_DIR}/${name}"
+                     "${CMAKE_CURRENT_BINARY_DIR}/${name}"
+    --build-config Release
+    --build-noclean
+    --build-generator ${CMAKE_GENERATOR}
+    $<$<BOOL:${CMAKE_GENERATOR_PLATFORM}>:--build-generator-platform> ${CMAKE_GENERATOR_PLATFORM}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-target check
+    --build-options ${build_options}
+  )
+  if(ARG_INSTALL)
+    add_dependencies(test_${name} mock_install)
+  endif()
+  add_dependencies(test_cmake_build test_${name})
+endfunction()
+
+pybind11_add_build_test(subdirectory_function)
+pybind11_add_build_test(subdirectory_target)
+if(NOT ${PYTHON_MODULE_EXTENSION} MATCHES "pypy")
+  pybind11_add_build_test(subdirectory_embed)
+endif()
+
+if(PYBIND11_INSTALL)
+  add_custom_target(mock_install ${CMAKE_COMMAND}
+    "-DCMAKE_INSTALL_PREFIX=${PROJECT_BINARY_DIR}/mock_install"
+    -P "${PROJECT_BINARY_DIR}/cmake_install.cmake"
+  )
+
+  pybind11_add_build_test(installed_function INSTALL)
+  pybind11_add_build_test(installed_target INSTALL)
+  if(NOT ${PYTHON_MODULE_EXTENSION} MATCHES "pypy")
+    pybind11_add_build_test(installed_embed INSTALL)
+  endif()
+endif()
+
+add_dependencies(check test_cmake_build)
diff --git a/ext/pybind11/tests/test_cmake_build/embed.cpp b/ext/pybind11/tests/test_cmake_build/embed.cpp
new file mode 100644
index 000000000..b9581d2fd
--- /dev/null
+++ b/ext/pybind11/tests/test_cmake_build/embed.cpp
@@ -0,0 +1,21 @@
+#include <pybind11/embed.h>
+namespace py = pybind11;
+
+PYBIND11_EMBEDDED_MODULE(test_cmake_build, m) {
+    m.def("add", [](int i, int j) { return i + j; });
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 2)
+        throw std::runtime_error("Expected test.py file as the first argument");
+    auto test_py_file = argv[1];
+
+    py::scoped_interpreter guard{};
+
+    auto m = py::module::import("test_cmake_build");
+    if (m.attr("add")(1, 2).cast<int>() != 3)
+        throw std::runtime_error("embed.cpp failed");
+
+    py::module::import("sys").attr("argv") = py::make_tuple("test.py", "embed.cpp");
+    py::eval_file(test_py_file, py::globals());
+}
diff --git a/ext/pybind11/tests/test_cmake_build/installed_embed/CMakeLists.txt b/ext/pybind11/tests/test_cmake_build/installed_embed/CMakeLists.txt
new file mode 100644
index 000000000..f7fc09c21
--- /dev/null
+++ b/ext/pybind11/tests/test_cmake_build/installed_embed/CMakeLists.txt
@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.0)
+project(test_installed_embed CXX)
+
+set(CMAKE_MODULE_PATH "")
+find_package(pybind11 CONFIG REQUIRED)
+message(STATUS "Found pybind11 v${pybind11_VERSION}: ${pybind11_INCLUDE_DIRS}")
+
+add_executable(test_cmake_build ../embed.cpp)
+target_link_libraries(test_cmake_build PRIVATE pybind11::embed)
+
+# Do not treat includes from IMPORTED target as SYSTEM (Python headers in pybind11::embed).
+# This may be needed to resolve header conflicts, e.g. between Python release and debug headers.
+set_target_properties(test_cmake_build PROPERTIES NO_SYSTEM_FROM_IMPORTED ON)
+
+add_custom_target(check $<TARGET_FILE:test_cmake_build> ${PROJECT_SOURCE_DIR}/../test.py)
diff --git a/ext/pybind11/tests/test_cmake_build/main.cpp b/ext/pybind11/tests/test_cmake_build/main.cpp
index e0f5b69c9..e30f2c4b9 100644
--- a/ext/pybind11/tests/test_cmake_build/main.cpp
+++ b/ext/pybind11/tests/test_cmake_build/main.cpp
@@ -1,10 +1,6 @@
 #include <pybind11/pybind11.h>
 namespace py = pybind11;
 
-PYBIND11_PLUGIN(test_cmake_build) {
-    py::module m("test_cmake_build");
-
+PYBIND11_MODULE(test_cmake_build, m) {
     m.def("add", [](int i, int j) { return i + j; });
-
-    return m.ptr();
 }
diff --git a/ext/pybind11/tests/test_cmake_build/subdirectory_embed/CMakeLists.txt b/ext/pybind11/tests/test_cmake_build/subdirectory_embed/CMakeLists.txt
new file mode 100644
index 000000000..88ba60dd5
--- /dev/null
+++ b/ext/pybind11/tests/test_cmake_build/subdirectory_embed/CMakeLists.txt
@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.0)
+project(test_subdirectory_embed CXX)
+
+set(PYBIND11_INSTALL ON CACHE BOOL "")
+set(PYBIND11_EXPORT_NAME test_export)
+
+add_subdirectory(${PYBIND11_PROJECT_DIR} pybind11)
+
+# Test basic target functionality
+add_executable(test_cmake_build ../embed.cpp)
+target_link_libraries(test_cmake_build PRIVATE pybind11::embed)
+
+add_custom_target(check $<TARGET_FILE:test_cmake_build> ${PROJECT_SOURCE_DIR}/../test.py)
+
+# Test custom export group -- PYBIND11_EXPORT_NAME
+add_library(test_embed_lib ../embed.cpp)
+target_link_libraries(test_embed_lib PRIVATE pybind11::embed)
+
+install(TARGETS test_embed_lib
+        EXPORT  test_export
+        ARCHIVE DESTINATION bin
+        LIBRARY DESTINATION lib
+        RUNTIME DESTINATION lib)
+install(EXPORT      test_export
+        DESTINATION lib/cmake/test_export/test_export-Targets.cmake)
diff --git a/ext/pybind11/tests/test_constants_and_functions.cpp b/ext/pybind11/tests/test_constants_and_functions.cpp
index 653bdf6b6..8c9ef7f67 100644
--- a/ext/pybind11/tests/test_constants_and_functions.cpp
+++ b/ext/pybind11/tests/test_constants_and_functions.cpp
@@ -23,6 +23,8 @@ std::string test_function3(int i) {
     return "test_function(" + std::to_string(i) + ")";
 }
 
+py::str test_function4()           { return "test_function()"; }
+py::str test_function4(char *)     { return "test_function(char *)"; }
 py::str test_function4(int, float) { return "test_function(int, float)"; }
 py::str test_function4(float, int) { return "test_function(float, int)"; }
 
@@ -61,17 +63,23 @@ struct C {
 }
 
 
-test_initializer constants_and_functions([](py::module &m) {
+TEST_SUBMODULE(constants_and_functions, m) {
+    // test_constants
     m.attr("some_constant") = py::int_(14);
 
+    // test_function_overloading
     m.def("test_function", &test_function1);
     m.def("test_function", &test_function2);
     m.def("test_function", &test_function3);
 
 #if defined(PYBIND11_OVERLOAD_CAST)
+    m.def("test_function", py::overload_cast<>(&test_function4));
+    m.def("test_function", py::overload_cast<char *>(&test_function4));
     m.def("test_function", py::overload_cast<int, float>(&test_function4));
     m.def("test_function", py::overload_cast<float, int>(&test_function4));
 #else
+    m.def("test_function", static_cast<py::str (*)()>(&test_function4));
+    m.def("test_function", static_cast<py::str (*)(char *)>(&test_function4));
     m.def("test_function", static_cast<py::str (*)(int, float)>(&test_function4));
     m.def("test_function", static_cast<py::str (*)(float, int)>(&test_function4));
 #endif
@@ -81,12 +89,13 @@ test_initializer constants_and_functions([](py::module &m) {
         .value("ESecondEntry", ESecondEntry)
         .export_values();
 
+    // test_bytes
     m.def("return_bytes", &return_bytes);
     m.def("print_bytes", &print_bytes);
 
+    // test_exception_specifiers
     using namespace test_exc_sp;
-    py::module m2 = m.def_submodule("exc_sp");
-    py::class_<C>(m2, "C")
+    py::class_<C>(m, "C")
         .def(py::init<>())
         .def("m1", &C::m1)
         .def("m2", &C::m2)
@@ -97,8 +106,8 @@ test_initializer constants_and_functions([](py::module &m) {
         .def("m7", &C::m7)
         .def("m8", &C::m8)
         ;
-    m2.def("f1", f1);
-    m2.def("f2", f2);
-    m2.def("f3", f3);
-    m2.def("f4", f4);
-});
+    m.def("f1", f1);
+    m.def("f2", f2);
+    m.def("f3", f3);
+    m.def("f4", f4);
+}
diff --git a/ext/pybind11/tests/test_constants_and_functions.py b/ext/pybind11/tests/test_constants_and_functions.py
index 2a570d2e5..472682d61 100644
--- a/ext/pybind11/tests/test_constants_and_functions.py
+++ b/ext/pybind11/tests/test_constants_and_functions.py
@@ -1,33 +1,29 @@
+from pybind11_tests import constants_and_functions as m
 
 
 def test_constants():
-    from pybind11_tests import some_constant
-
-    assert some_constant == 14
+    assert m.some_constant == 14
 
 
 def test_function_overloading():
-    from pybind11_tests import MyEnum, test_function
-
-    assert test_function() == "test_function()"
-    assert test_function(7) == "test_function(7)"
-    assert test_function(MyEnum.EFirstEntry) == "test_function(enum=1)"
-    assert test_function(MyEnum.ESecondEntry) == "test_function(enum=2)"
+    assert m.test_function() == "test_function()"
+    assert m.test_function(7) == "test_function(7)"
+    assert m.test_function(m.MyEnum.EFirstEntry) == "test_function(enum=1)"
+    assert m.test_function(m.MyEnum.ESecondEntry) == "test_function(enum=2)"
 
-    assert test_function(1, 1.0) == "test_function(int, float)"
-    assert test_function(2.0, 2) == "test_function(float, int)"
+    assert m.test_function() == "test_function()"
+    assert m.test_function("abcd") == "test_function(char *)"
+    assert m.test_function(1, 1.0) == "test_function(int, float)"
+    assert m.test_function(1, 1.0) == "test_function(int, float)"
+    assert m.test_function(2.0, 2) == "test_function(float, int)"
 
 
 def test_bytes():
-    from pybind11_tests import return_bytes, print_bytes
-
-    assert print_bytes(return_bytes()) == "bytes[1 0 2 0]"
+    assert m.print_bytes(m.return_bytes()) == "bytes[1 0 2 0]"
 
 
 def test_exception_specifiers():
-    from pybind11_tests.exc_sp import C, f1, f2, f3, f4
-
-    c = C()
+    c = m.C()
     assert c.m1(2) == 1
     assert c.m2(3) == 1
     assert c.m3(5) == 2
@@ -37,7 +33,7 @@ def test_exception_specifiers():
     assert c.m7(20) == 13
     assert c.m8(29) == 21
 
-    assert f1(33) == 34
-    assert f2(53) == 55
-    assert f3(86) == 89
-    assert f4(140) == 144
+    assert m.f1(33) == 34
+    assert m.f2(53) == 55
+    assert m.f3(86) == 89
+    assert m.f4(140) == 144
diff --git a/ext/pybind11/tests/test_copy_move.cpp b/ext/pybind11/tests/test_copy_move.cpp
new file mode 100644
index 000000000..94113e3af
--- /dev/null
+++ b/ext/pybind11/tests/test_copy_move.cpp
@@ -0,0 +1,213 @@
+/*
+    tests/test_copy_move_policies.cpp -- 'copy' and 'move' return value policies
+                                         and related tests
+
+    Copyright (c) 2016 Ben North <ben@redfrontdoor.org>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include "constructor_stats.h"
+#include <pybind11/stl.h>
+
+template <typename derived>
+struct empty {
+    static const derived& get_one() { return instance_; }
+    static derived instance_;
+};
+
+struct lacking_copy_ctor : public empty<lacking_copy_ctor> {
+    lacking_copy_ctor() {}
+    lacking_copy_ctor(const lacking_copy_ctor& other) = delete;
+};
+
+template <> lacking_copy_ctor empty<lacking_copy_ctor>::instance_ = {};
+
+struct lacking_move_ctor : public empty<lacking_move_ctor> {
+    lacking_move_ctor() {}
+    lacking_move_ctor(const lacking_move_ctor& other) = delete;
+    lacking_move_ctor(lacking_move_ctor&& other) = delete;
+};
+
+template <> lacking_move_ctor empty<lacking_move_ctor>::instance_ = {};
+
+/* Custom type caster move/copy test classes */
+class MoveOnlyInt {
+public:
+    MoveOnlyInt() { print_default_created(this); }
+    MoveOnlyInt(int v) : value{std::move(v)} { print_created(this, value); }
+    MoveOnlyInt(MoveOnlyInt &&m) { print_move_created(this, m.value); std::swap(value, m.value); }
+    MoveOnlyInt &operator=(MoveOnlyInt &&m) { print_move_assigned(this, m.value); std::swap(value, m.value); return *this; }
+    MoveOnlyInt(const MoveOnlyInt &) = delete;
+    MoveOnlyInt &operator=(const MoveOnlyInt &) = delete;
+    ~MoveOnlyInt() { print_destroyed(this); }
+
+    int value;
+};
+class MoveOrCopyInt {
+public:
+    MoveOrCopyInt() { print_default_created(this); }
+    MoveOrCopyInt(int v) : value{std::move(v)} { print_created(this, value); }
+    MoveOrCopyInt(MoveOrCopyInt &&m) { print_move_created(this, m.value); std::swap(value, m.value); }
+    MoveOrCopyInt &operator=(MoveOrCopyInt &&m) { print_move_assigned(this, m.value); std::swap(value, m.value); return *this; }
+    MoveOrCopyInt(const MoveOrCopyInt &c) { print_copy_created(this, c.value); value = c.value; }
+    MoveOrCopyInt &operator=(const MoveOrCopyInt &c) { print_copy_assigned(this, c.value); value = c.value; return *this; }
+    ~MoveOrCopyInt() { print_destroyed(this); }
+
+    int value;
+};
+class CopyOnlyInt {
+public:
+    CopyOnlyInt() { print_default_created(this); }
+    CopyOnlyInt(int v) : value{std::move(v)} { print_created(this, value); }
+    CopyOnlyInt(const CopyOnlyInt &c) { print_copy_created(this, c.value); value = c.value; }
+    CopyOnlyInt &operator=(const CopyOnlyInt &c) { print_copy_assigned(this, c.value); value = c.value; return *this; }
+    ~CopyOnlyInt() { print_destroyed(this); }
+
+    int value;
+};
+NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(detail)
+template <> struct type_caster<MoveOnlyInt> {
+    PYBIND11_TYPE_CASTER(MoveOnlyInt, _("MoveOnlyInt"));
+    bool load(handle src, bool) { value = MoveOnlyInt(src.cast<int>()); return true; }
+    static handle cast(const MoveOnlyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
+};
+
+template <> struct type_caster<MoveOrCopyInt> {
+    PYBIND11_TYPE_CASTER(MoveOrCopyInt, _("MoveOrCopyInt"));
+    bool load(handle src, bool) { value = MoveOrCopyInt(src.cast<int>()); return true; }
+    static handle cast(const MoveOrCopyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
+};
+
+template <> struct type_caster<CopyOnlyInt> {
+protected:
+    CopyOnlyInt value;
+public:
+    static PYBIND11_DESCR name() { return _("CopyOnlyInt"); }
+    bool load(handle src, bool) { value = CopyOnlyInt(src.cast<int>()); return true; }
+    static handle cast(const CopyOnlyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
+    static handle cast(const CopyOnlyInt *src, return_value_policy policy, handle parent) {
+        if (!src) return none().release();
+        return cast(*src, policy, parent);
+    }
+    operator CopyOnlyInt*() { return &value; }
+    operator CopyOnlyInt&() { return value; }
+    template <typename T> using cast_op_type = pybind11::detail::cast_op_type<T>;
+};
+NAMESPACE_END(detail)
+NAMESPACE_END(pybind11)
+
+TEST_SUBMODULE(copy_move_policies, m) {
+    // test_lacking_copy_ctor
+    py::class_<lacking_copy_ctor>(m, "lacking_copy_ctor")
+        .def_static("get_one", &lacking_copy_ctor::get_one,
+                    py::return_value_policy::copy);
+    // test_lacking_move_ctor
+    py::class_<lacking_move_ctor>(m, "lacking_move_ctor")
+        .def_static("get_one", &lacking_move_ctor::get_one,
+                    py::return_value_policy::move);
+
+    // test_move_and_copy_casts
+    m.def("move_and_copy_casts", [](py::object o) {
+        int r = 0;
+        r += py::cast<MoveOrCopyInt>(o).value; /* moves */
+        r += py::cast<MoveOnlyInt>(o).value; /* moves */
+        r += py::cast<CopyOnlyInt>(o).value; /* copies */
+        MoveOrCopyInt m1(py::cast<MoveOrCopyInt>(o)); /* moves */
+        MoveOnlyInt m2(py::cast<MoveOnlyInt>(o)); /* moves */
+        CopyOnlyInt m3(py::cast<CopyOnlyInt>(o)); /* copies */
+        r += m1.value + m2.value + m3.value;
+
+        return r;
+    });
+
+    // test_move_and_copy_loads
+    m.def("move_only", [](MoveOnlyInt m) { return m.value; });
+    m.def("move_or_copy", [](MoveOrCopyInt m) { return m.value; });
+    m.def("copy_only", [](CopyOnlyInt m) { return m.value; });
+    m.def("move_pair", [](std::pair<MoveOnlyInt, MoveOrCopyInt> p) {
+        return p.first.value + p.second.value;
+    });
+    m.def("move_tuple", [](std::tuple<MoveOnlyInt, MoveOrCopyInt, MoveOnlyInt> t) {
+        return std::get<0>(t).value + std::get<1>(t).value + std::get<2>(t).value;
+    });
+    m.def("copy_tuple", [](std::tuple<CopyOnlyInt, CopyOnlyInt> t) {
+        return std::get<0>(t).value + std::get<1>(t).value;
+    });
+    m.def("move_copy_nested", [](std::pair<MoveOnlyInt, std::pair<std::tuple<MoveOrCopyInt, CopyOnlyInt, std::tuple<MoveOnlyInt>>, MoveOrCopyInt>> x) {
+        return x.first.value + std::get<0>(x.second.first).value + std::get<1>(x.second.first).value +
+            std::get<0>(std::get<2>(x.second.first)).value + x.second.second.value;
+    });
+    m.def("move_and_copy_cstats", []() {
+        ConstructorStats::gc();
+        // Reset counts to 0 so that previous tests don't affect later ones:
+        auto &mc = ConstructorStats::get<MoveOrCopyInt>();
+        mc.move_assignments = mc.move_constructions = mc.copy_assignments = mc.copy_constructions = 0;
+        auto &mo = ConstructorStats::get<MoveOnlyInt>();
+        mo.move_assignments = mo.move_constructions = mo.copy_assignments = mo.copy_constructions = 0;
+        auto &co = ConstructorStats::get<CopyOnlyInt>();
+        co.move_assignments = co.move_constructions = co.copy_assignments = co.copy_constructions = 0;
+        py::dict d;
+        d["MoveOrCopyInt"] = py::cast(mc, py::return_value_policy::reference);
+        d["MoveOnlyInt"] = py::cast(mo, py::return_value_policy::reference);
+        d["CopyOnlyInt"] = py::cast(co, py::return_value_policy::reference);
+        return d;
+    });
+#ifdef PYBIND11_HAS_OPTIONAL
+    // test_move_and_copy_load_optional
+    m.attr("has_optional") = true;
+    m.def("move_optional", [](std::optional<MoveOnlyInt> o) {
+        return o->value;
+    });
+    m.def("move_or_copy_optional", [](std::optional<MoveOrCopyInt> o) {
+        return o->value;
+    });
+    m.def("copy_optional", [](std::optional<CopyOnlyInt> o) {
+        return o->value;
+    });
+    m.def("move_optional_tuple", [](std::optional<std::tuple<MoveOrCopyInt, MoveOnlyInt, CopyOnlyInt>> x) {
+        return std::get<0>(*x).value + std::get<1>(*x).value + std::get<2>(*x).value;
+    });
+#else
+    m.attr("has_optional") = false;
+#endif
+
+    // #70 compilation issue if operator new is not public
+    struct PrivateOpNew {
+        int value = 1;
+    private:
+#if defined(_MSC_VER)
+#  pragma warning(disable: 4822) // warning C4822: local class member function does not have a body
+#endif
+        void *operator new(size_t bytes);
+    };
+    py::class_<PrivateOpNew>(m, "PrivateOpNew").def_readonly("value", &PrivateOpNew::value);
+    m.def("private_op_new_value", []() { return PrivateOpNew(); });
+    m.def("private_op_new_reference", []() -> const PrivateOpNew & {
+        static PrivateOpNew x{};
+        return x;
+    }, py::return_value_policy::reference);
+
+    // test_move_fallback
+    // #389: rvp::move should fall-through to copy on non-movable objects
+    struct MoveIssue1 {
+        int v;
+        MoveIssue1(int v) : v{v} {}
+        MoveIssue1(const MoveIssue1 &c) = default;
+        MoveIssue1(MoveIssue1 &&) = delete;
+    };
+    py::class_<MoveIssue1>(m, "MoveIssue1").def(py::init<int>()).def_readwrite("value", &MoveIssue1::v);
+
+    struct MoveIssue2 {
+        int v;
+        MoveIssue2(int v) : v{v} {}
+        MoveIssue2(MoveIssue2 &&) = default;
+    };
+    py::class_<MoveIssue2>(m, "MoveIssue2").def(py::init<int>()).def_readwrite("value", &MoveIssue2::v);
+
+    m.def("get_moveissue1", [](int i) { return new MoveIssue1(i); }, py::return_value_policy::move);
+    m.def("get_moveissue2", [](int i) { return MoveIssue2(i); }, py::return_value_policy::move);
+}
diff --git a/ext/pybind11/tests/test_copy_move.py b/ext/pybind11/tests/test_copy_move.py
new file mode 100644
index 000000000..aff2d99f2
--- /dev/null
+++ b/ext/pybind11/tests/test_copy_move.py
@@ -0,0 +1,112 @@
+import pytest
+from pybind11_tests import copy_move_policies as m
+
+
+def test_lacking_copy_ctor():
+    with pytest.raises(RuntimeError) as excinfo:
+        m.lacking_copy_ctor.get_one()
+    assert "the object is non-copyable!" in str(excinfo.value)
+
+
+def test_lacking_move_ctor():
+    with pytest.raises(RuntimeError) as excinfo:
+        m.lacking_move_ctor.get_one()
+    assert "the object is neither movable nor copyable!" in str(excinfo.value)
+
+
+def test_move_and_copy_casts():
+    """Cast some values in C++ via custom type casters and count the number of moves/copies."""
+
+    cstats = m.move_and_copy_cstats()
+    c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
+
+    # The type move constructions/assignments below each get incremented: the move assignment comes
+    # from the type_caster load; the move construction happens when extracting that via a cast or
+    # loading into an argument.
+    assert m.move_and_copy_casts(3) == 18
+    assert c_m.copy_assignments + c_m.copy_constructions == 0
+    assert c_m.move_assignments == 2
+    assert c_m.move_constructions >= 2
+    assert c_mc.alive() == 0
+    assert c_mc.copy_assignments + c_mc.copy_constructions == 0
+    assert c_mc.move_assignments == 2
+    assert c_mc.move_constructions >= 2
+    assert c_c.alive() == 0
+    assert c_c.copy_assignments == 2
+    assert c_c.copy_constructions >= 2
+    assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
+
+
+def test_move_and_copy_loads():
+    """Call some functions that load arguments via custom type casters and count the number of
+    moves/copies."""
+
+    cstats = m.move_and_copy_cstats()
+    c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
+
+    assert m.move_only(10) == 10  # 1 move, c_m
+    assert m.move_or_copy(11) == 11  # 1 move, c_mc
+    assert m.copy_only(12) == 12  # 1 copy, c_c
+    assert m.move_pair((13, 14)) == 27  # 1 c_m move, 1 c_mc move
+    assert m.move_tuple((15, 16, 17)) == 48  # 2 c_m moves, 1 c_mc move
+    assert m.copy_tuple((18, 19)) == 37  # 2 c_c copies
+    # Direct constructions: 2 c_m moves, 2 c_mc moves, 1 c_c copy
+    # Extra moves/copies when moving pairs/tuples: 3 c_m, 3 c_mc, 2 c_c
+    assert m.move_copy_nested((1, ((2, 3, (4,)), 5))) == 15
+
+    assert c_m.copy_assignments + c_m.copy_constructions == 0
+    assert c_m.move_assignments == 6
+    assert c_m.move_constructions == 9
+    assert c_mc.copy_assignments + c_mc.copy_constructions == 0
+    assert c_mc.move_assignments == 5
+    assert c_mc.move_constructions == 8
+    assert c_c.copy_assignments == 4
+    assert c_c.copy_constructions == 6
+    assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
+
+
+@pytest.mark.skipif(not m.has_optional, reason='no <optional>')
+def test_move_and_copy_load_optional():
+    """Tests move/copy loads of std::optional arguments"""
+
+    cstats = m.move_and_copy_cstats()
+    c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
+
+    # The extra move/copy constructions below come from the std::optional move (which has to move
+    # its arguments):
+    assert m.move_optional(10) == 10  # c_m: 1 move assign, 2 move construct
+    assert m.move_or_copy_optional(11) == 11  # c_mc: 1 move assign, 2 move construct
+    assert m.copy_optional(12) == 12  # c_c: 1 copy assign, 2 copy construct
+    # 1 move assign + move construct moves each of c_m, c_mc, 1 c_c copy
+    # +1 move/copy construct each from moving the tuple
+    # +1 move/copy construct each from moving the optional (which moves the tuple again)
+    assert m.move_optional_tuple((3, 4, 5)) == 12
+
+    assert c_m.copy_assignments + c_m.copy_constructions == 0
+    assert c_m.move_assignments == 2
+    assert c_m.move_constructions == 5
+    assert c_mc.copy_assignments + c_mc.copy_constructions == 0
+    assert c_mc.move_assignments == 2
+    assert c_mc.move_constructions == 5
+    assert c_c.copy_assignments == 2
+    assert c_c.copy_constructions == 5
+    assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
+
+
+def test_private_op_new():
+    """An object with a private `operator new` cannot be returned by value"""
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.private_op_new_value()
+    assert "the object is neither movable nor copyable" in str(excinfo.value)
+
+    assert m.private_op_new_reference().value == 1
+
+
+def test_move_fallback():
+    """#389: rvp::move should fall-through to copy on non-movable objects"""
+
+    m2 = m.get_moveissue2(2)
+    assert m2.value == 2
+    m1 = m.get_moveissue1(1)
+    assert m1.value == 1
diff --git a/ext/pybind11/tests/test_copy_move_policies.cpp b/ext/pybind11/tests/test_copy_move_policies.cpp
deleted file mode 100644
index 6f7907c1f..000000000
--- a/ext/pybind11/tests/test_copy_move_policies.cpp
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
-    tests/test_copy_move_policies.cpp -- 'copy' and 'move'
-                                         return value policies
-
-    Copyright (c) 2016 Ben North <ben@redfrontdoor.org>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-template <typename derived>
-struct empty {
-    static const derived& get_one() { return instance_; }
-    static derived instance_;
-};
-
-struct lacking_copy_ctor : public empty<lacking_copy_ctor> {
-    lacking_copy_ctor() {}
-    lacking_copy_ctor(const lacking_copy_ctor& other) = delete;
-};
-
-template <> lacking_copy_ctor empty<lacking_copy_ctor>::instance_ = {};
-
-struct lacking_move_ctor : public empty<lacking_move_ctor> {
-    lacking_move_ctor() {}
-    lacking_move_ctor(const lacking_move_ctor& other) = delete;
-    lacking_move_ctor(lacking_move_ctor&& other) = delete;
-};
-
-template <> lacking_move_ctor empty<lacking_move_ctor>::instance_ = {};
-
-test_initializer copy_move_policies([](py::module &m) {
-    py::class_<lacking_copy_ctor>(m, "lacking_copy_ctor")
-        .def_static("get_one", &lacking_copy_ctor::get_one,
-                    py::return_value_policy::copy);
-    py::class_<lacking_move_ctor>(m, "lacking_move_ctor")
-        .def_static("get_one", &lacking_move_ctor::get_one,
-                    py::return_value_policy::move);
-});
diff --git a/ext/pybind11/tests/test_copy_move_policies.py b/ext/pybind11/tests/test_copy_move_policies.py
deleted file mode 100644
index edcf38075..000000000
--- a/ext/pybind11/tests/test_copy_move_policies.py
+++ /dev/null
@@ -1,15 +0,0 @@
-import pytest
-
-
-def test_lacking_copy_ctor():
-    from pybind11_tests import lacking_copy_ctor
-    with pytest.raises(RuntimeError) as excinfo:
-        lacking_copy_ctor.get_one()
-    assert "the object is non-copyable!" in str(excinfo.value)
-
-
-def test_lacking_move_ctor():
-    from pybind11_tests import lacking_move_ctor
-    with pytest.raises(RuntimeError) as excinfo:
-        lacking_move_ctor.get_one()
-    assert "the object is neither movable nor copyable!" in str(excinfo.value)
diff --git a/ext/pybind11/tests/test_docstring_options.cpp b/ext/pybind11/tests/test_docstring_options.cpp
index 9a9297cc3..8c8f79fd5 100644
--- a/ext/pybind11/tests/test_docstring_options.cpp
+++ b/ext/pybind11/tests/test_docstring_options.cpp
@@ -9,14 +9,8 @@
 
 #include "pybind11_tests.h"
 
-struct DocstringTestFoo {
-    int value;
-    void setValue(int v) { value = v; }
-    int getValue() const { return value; }
-};
-
-test_initializer docstring_generation([](py::module &m) {
-
+TEST_SUBMODULE(docstring_options, m) {
+    // test_docstring_options
     {
         py::options options;
         options.disable_function_signatures();
@@ -55,8 +49,13 @@ test_initializer docstring_generation([](py::module &m) {
         py::options options;
         options.disable_user_defined_docstrings();
 
+        struct DocstringTestFoo {
+            int value;
+            void setValue(int v) { value = v; }
+            int getValue() const { return value; }
+        };
         py::class_<DocstringTestFoo>(m, "DocstringTestFoo", "This is a class docstring")
             .def_property("value_prop", &DocstringTestFoo::getValue, &DocstringTestFoo::setValue, "This is a property docstring")
         ;
     }
-});
+}
diff --git a/ext/pybind11/tests/test_docstring_options.py b/ext/pybind11/tests/test_docstring_options.py
index 5e40f6868..0dbca609e 100644
--- a/ext/pybind11/tests/test_docstring_options.py
+++ b/ext/pybind11/tests/test_docstring_options.py
@@ -1,42 +1,38 @@
+from pybind11_tests import docstring_options as m
 
 
 def test_docstring_options():
-    from pybind11_tests import (test_function1, test_function2, test_function3,
-                                test_function4, test_function5, test_function6,
-                                test_function7, DocstringTestFoo,
-                                test_overloaded1, test_overloaded2, test_overloaded3)
-
     # options.disable_function_signatures()
-    assert not test_function1.__doc__
+    assert not m.test_function1.__doc__
 
-    assert test_function2.__doc__ == "A custom docstring"
+    assert m.test_function2.__doc__ == "A custom docstring"
 
     # docstring specified on just the first overload definition:
-    assert test_overloaded1.__doc__ == "Overload docstring"
+    assert m.test_overloaded1.__doc__ == "Overload docstring"
 
     # docstring on both overloads:
-    assert test_overloaded2.__doc__ == "overload docstring 1\noverload docstring 2"
+    assert m.test_overloaded2.__doc__ == "overload docstring 1\noverload docstring 2"
 
     # docstring on only second overload:
-    assert test_overloaded3.__doc__ == "Overload docstr"
+    assert m.test_overloaded3.__doc__ == "Overload docstr"
 
     # options.enable_function_signatures()
-    assert test_function3.__doc__ .startswith("test_function3(a: int, b: int) -> None")
+    assert m.test_function3.__doc__ .startswith("test_function3(a: int, b: int) -> None")
 
-    assert test_function4.__doc__ .startswith("test_function4(a: int, b: int) -> None")
-    assert test_function4.__doc__ .endswith("A custom docstring\n")
+    assert m.test_function4.__doc__ .startswith("test_function4(a: int, b: int) -> None")
+    assert m.test_function4.__doc__ .endswith("A custom docstring\n")
 
     # options.disable_function_signatures()
     # options.disable_user_defined_docstrings()
-    assert not test_function5.__doc__
+    assert not m.test_function5.__doc__
 
     # nested options.enable_user_defined_docstrings()
-    assert test_function6.__doc__ == "A custom docstring"
+    assert m.test_function6.__doc__ == "A custom docstring"
 
     # RAII destructor
-    assert test_function7.__doc__ .startswith("test_function7(a: int, b: int) -> None")
-    assert test_function7.__doc__ .endswith("A custom docstring\n")
+    assert m.test_function7.__doc__ .startswith("test_function7(a: int, b: int) -> None")
+    assert m.test_function7.__doc__ .endswith("A custom docstring\n")
 
     # Suppression of user-defined docstrings for non-function objects
-    assert not DocstringTestFoo.__doc__
-    assert not DocstringTestFoo.value_prop.__doc__
+    assert not m.DocstringTestFoo.__doc__
+    assert not m.DocstringTestFoo.value_prop.__doc__
diff --git a/ext/pybind11/tests/test_eigen.cpp b/ext/pybind11/tests/test_eigen.cpp
index f2ec8fd2e..17b156ce4 100644
--- a/ext/pybind11/tests/test_eigen.cpp
+++ b/ext/pybind11/tests/test_eigen.cpp
@@ -10,6 +10,7 @@
 #include "pybind11_tests.h"
 #include "constructor_stats.h"
 #include <pybind11/eigen.h>
+#include <pybind11/stl.h>
 #include <Eigen/Cholesky>
 
 using MatrixXdR = Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
@@ -69,20 +70,21 @@ struct CustomOperatorNew {
     EIGEN_MAKE_ALIGNED_OPERATOR_NEW;
 };
 
-test_initializer eigen([](py::module &m) {
-    typedef Eigen::Matrix<float, 5, 6, Eigen::RowMajor> FixedMatrixR;
-    typedef Eigen::Matrix<float, 5, 6> FixedMatrixC;
-    typedef Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor> DenseMatrixR;
-    typedef Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic> DenseMatrixC;
-    typedef Eigen::Matrix<float, 4, Eigen::Dynamic> FourRowMatrixC;
-    typedef Eigen::Matrix<float, Eigen::Dynamic, 4> FourColMatrixC;
-    typedef Eigen::Matrix<float, 4, Eigen::Dynamic> FourRowMatrixR;
-    typedef Eigen::Matrix<float, Eigen::Dynamic, 4> FourColMatrixR;
-    typedef Eigen::SparseMatrix<float, Eigen::RowMajor> SparseMatrixR;
-    typedef Eigen::SparseMatrix<float> SparseMatrixC;
+TEST_SUBMODULE(eigen, m) {
+    using FixedMatrixR = Eigen::Matrix<float, 5, 6, Eigen::RowMajor>;
+    using FixedMatrixC = Eigen::Matrix<float, 5, 6>;
+    using DenseMatrixR = Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
+    using DenseMatrixC = Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic>;
+    using FourRowMatrixC = Eigen::Matrix<float, 4, Eigen::Dynamic>;
+    using FourColMatrixC = Eigen::Matrix<float, Eigen::Dynamic, 4>;
+    using FourRowMatrixR = Eigen::Matrix<float, 4, Eigen::Dynamic>;
+    using FourColMatrixR = Eigen::Matrix<float, Eigen::Dynamic, 4>;
+    using SparseMatrixR = Eigen::SparseMatrix<float, Eigen::RowMajor>;
+    using SparseMatrixC = Eigen::SparseMatrix<float>;
 
     m.attr("have_eigen") = true;
 
+    // various tests
     m.def("double_col", [](const Eigen::VectorXf &x) -> Eigen::VectorXf { return 2.0f * x; });
     m.def("double_row", [](const Eigen::RowVectorXf &x) -> Eigen::RowVectorXf { return 2.0f * x; });
     m.def("double_complex", [](const Eigen::VectorXcf &x) -> Eigen::VectorXcf { return 2.0f * x; });
@@ -91,12 +93,14 @@ test_initializer eigen([](py::module &m) {
     m.def("double_mat_cm", [](Eigen::MatrixXf x) -> Eigen::MatrixXf { return 2.0f * x; });
     m.def("double_mat_rm", [](DenseMatrixR x) -> DenseMatrixR { return 2.0f * x; });
 
+    // test_eigen_ref_to_python
     // Different ways of passing via Eigen::Ref; the first and second are the Eigen-recommended
     m.def("cholesky1", [](Eigen::Ref<MatrixXdR> x) -> Eigen::MatrixXd { return x.llt().matrixL(); });
     m.def("cholesky2", [](const Eigen::Ref<const MatrixXdR> &x) -> Eigen::MatrixXd { return x.llt().matrixL(); });
     m.def("cholesky3", [](const Eigen::Ref<MatrixXdR> &x) -> Eigen::MatrixXd { return x.llt().matrixL(); });
     m.def("cholesky4", [](Eigen::Ref<const MatrixXdR> x) -> Eigen::MatrixXd { return x.llt().matrixL(); });
 
+    // test_eigen_ref_mutators
     // Mutators: these add some value to the given element using Eigen, but Eigen should be mapping into
     // the numpy array data and so the result should show up there.  There are three versions: one that
     // works on a contiguous-row matrix (numpy's default), one for a contiguous-column matrix, and one
@@ -121,19 +125,6 @@ test_initializer eigen([](py::module &m) {
     // The same references, but non-mutable (numpy maps into eigen variables, but is !writeable)
     m.def("get_cm_const_ref", []() { return Eigen::Ref<const Eigen::MatrixXd>(get_cm()); });
     m.def("get_rm_const_ref", []() { return Eigen::Ref<const MatrixXdR>(get_rm()); });
-    // Just the corners (via a Map instead of a Ref):
-    m.def("get_cm_corners", []() {
-        auto &x = get_cm();
-        return py::EigenDMap<Eigen::Matrix2d>(
-                x.data(),
-                py::EigenDStride(x.outerStride() * (x.rows() - 1), x.innerStride() * (x.cols() - 1)));
-    });
-    m.def("get_cm_corners_const", []() {
-        const auto &x = get_cm();
-        return py::EigenDMap<const Eigen::Matrix2d>(
-                x.data(),
-                py::EigenDStride(x.outerStride() * (x.rows() - 1), x.innerStride() * (x.cols() - 1)));
-    });
 
     m.def("reset_refs", reset_refs); // Restores get_{cm,rm}_ref to original values
 
@@ -173,6 +164,7 @@ test_initializer eigen([](py::module &m) {
         return x.block(start_row, start_col, block_rows, block_cols);
     });
 
+    // test_eigen_return_references, test_eigen_keepalive
     // return value referencing/copying tests:
     class ReturnTester {
         Eigen::MatrixXd mat = create();
@@ -219,6 +211,7 @@ test_initializer eigen([](py::module &m) {
         .def("corners_const", &ReturnTester::cornersConst, rvp::reference_internal)
         ;
 
+    // test_special_matrix_objects
     // Returns a DiagonalMatrix with diagonal (1,2,3,...)
     m.def("incr_diag", [](int k) {
         Eigen::DiagonalMatrix<int, Eigen::Dynamic> m(k);
@@ -243,27 +236,33 @@ test_initializer eigen([](py::module &m) {
            0,  0,  0,  0,  0, 11,
            0,  0, 14,  0,  8, 11;
 
+    // test_fixed, and various other tests
     m.def("fixed_r", [mat]() -> FixedMatrixR { return FixedMatrixR(mat); });
     m.def("fixed_r_const", [mat]() -> const FixedMatrixR { return FixedMatrixR(mat); });
     m.def("fixed_c", [mat]() -> FixedMatrixC { return FixedMatrixC(mat); });
     m.def("fixed_copy_r", [](const FixedMatrixR &m) -> FixedMatrixR { return m; });
     m.def("fixed_copy_c", [](const FixedMatrixC &m) -> FixedMatrixC { return m; });
+    // test_mutator_descriptors
     m.def("fixed_mutator_r", [](Eigen::Ref<FixedMatrixR>) {});
     m.def("fixed_mutator_c", [](Eigen::Ref<FixedMatrixC>) {});
     m.def("fixed_mutator_a", [](py::EigenDRef<FixedMatrixC>) {});
+    // test_dense
     m.def("dense_r", [mat]() -> DenseMatrixR { return DenseMatrixR(mat); });
     m.def("dense_c", [mat]() -> DenseMatrixC { return DenseMatrixC(mat); });
     m.def("dense_copy_r", [](const DenseMatrixR &m) -> DenseMatrixR { return m; });
     m.def("dense_copy_c", [](const DenseMatrixC &m) -> DenseMatrixC { return m; });
+    // test_sparse, test_sparse_signature
     m.def("sparse_r", [mat]() -> SparseMatrixR { return Eigen::SparseView<Eigen::MatrixXf>(mat); });
     m.def("sparse_c", [mat]() -> SparseMatrixC { return Eigen::SparseView<Eigen::MatrixXf>(mat); });
     m.def("sparse_copy_r", [](const SparseMatrixR &m) -> SparseMatrixR { return m; });
     m.def("sparse_copy_c", [](const SparseMatrixC &m) -> SparseMatrixC { return m; });
+    // test_partially_fixed
     m.def("partial_copy_four_rm_r", [](const FourRowMatrixR &m) -> FourRowMatrixR { return m; });
     m.def("partial_copy_four_rm_c", [](const FourColMatrixR &m) -> FourColMatrixR { return m; });
     m.def("partial_copy_four_cm_r", [](const FourRowMatrixC &m) -> FourRowMatrixC { return m; });
     m.def("partial_copy_four_cm_c", [](const FourColMatrixC &m) -> FourColMatrixC { return m; });
 
+    // test_cpp_casting
     // Test that we can cast a numpy object to a Eigen::MatrixXd explicitly
     m.def("cpp_copy", [](py::handle m) { return m.cast<Eigen::MatrixXd>()(1, 0); });
     m.def("cpp_ref_c", [](py::handle m) { return m.cast<Eigen::Ref<Eigen::MatrixXd>>()(1, 0); });
@@ -271,6 +270,7 @@ test_initializer eigen([](py::module &m) {
     m.def("cpp_ref_any", [](py::handle m) { return m.cast<py::EigenDRef<Eigen::MatrixXd>>()(1, 0); });
 
 
+    // test_nocopy_wrapper
     // Test that we can prevent copying into an argument that would normally copy: First a version
     // that would allow copying (if types or strides don't match) for comparison:
     m.def("get_elem", &get_elem);
@@ -281,14 +281,37 @@ test_initializer eigen([](py::module &m) {
     m.def("get_elem_rm_nocopy", [](Eigen::Ref<const Eigen::Matrix<long, -1, -1, Eigen::RowMajor>> &m) -> long { return m(2, 1); },
             py::arg().noconvert());
 
+    // test_issue738
     // Issue #738: 1xN or Nx1 2D matrices were neither accepted nor properly copied with an
     // incompatible stride value on the length-1 dimension--but that should be allowed (without
     // requiring a copy!) because the stride value can be safely ignored on a size-1 dimension.
     m.def("iss738_f1", &adjust_matrix<const Eigen::Ref<const Eigen::MatrixXd> &>, py::arg().noconvert());
     m.def("iss738_f2", &adjust_matrix<const Eigen::Ref<const Eigen::Matrix<double, -1, -1, Eigen::RowMajor>> &>, py::arg().noconvert());
 
+    // test_named_arguments
+    // Make sure named arguments are working properly:
+    m.def("matrix_multiply", [](const py::EigenDRef<const Eigen::MatrixXd> A, const py::EigenDRef<const Eigen::MatrixXd> B)
+            -> Eigen::MatrixXd {
+        if (A.cols() != B.rows()) throw std::domain_error("Nonconformable matrices!");
+        return A * B;
+    }, py::arg("A"), py::arg("B"));
+
+    // test_custom_operator_new
     py::class_<CustomOperatorNew>(m, "CustomOperatorNew")
         .def(py::init<>())
         .def_readonly("a", &CustomOperatorNew::a)
         .def_readonly("b", &CustomOperatorNew::b);
-});
+
+    // test_eigen_ref_life_support
+    // In case of a failure (the caster's temp array does not live long enough), creating
+    // a new array (np.ones(10)) increases the chances that the temp array will be garbage
+    // collected and/or that its memory will be overridden with different values.
+    m.def("get_elem_direct", [](Eigen::Ref<const Eigen::VectorXd> v) {
+        py::module::import("numpy").attr("ones")(10);
+        return v(5);
+    });
+    m.def("get_elem_indirect", [](std::vector<Eigen::Ref<const Eigen::VectorXd>> v) {
+        py::module::import("numpy").attr("ones")(10);
+        return v[0](5);
+    });
+}
diff --git a/ext/pybind11/tests/test_eigen.py b/ext/pybind11/tests/test_eigen.py
index df08edf3d..4ac8cbf5d 100644
--- a/ext/pybind11/tests/test_eigen.py
+++ b/ext/pybind11/tests/test_eigen.py
@@ -1,8 +1,10 @@
 import pytest
+from pybind11_tests import ConstructorStats
 
 pytestmark = pytest.requires_eigen_and_numpy
 
 with pytest.suppress(ImportError):
+    from pybind11_tests import eigen as m
     import numpy as np
 
     ref = np.array([[ 0.,  3,  0,  0,  0, 11],
@@ -21,156 +23,190 @@ def assert_sparse_equal_ref(sparse_mat):
 
 
 def test_fixed():
-    from pybind11_tests import fixed_r, fixed_c, fixed_copy_r, fixed_copy_c
-
-    assert_equal_ref(fixed_c())
-    assert_equal_ref(fixed_r())
-    assert_equal_ref(fixed_copy_r(fixed_r()))
-    assert_equal_ref(fixed_copy_c(fixed_c()))
-    assert_equal_ref(fixed_copy_r(fixed_c()))
-    assert_equal_ref(fixed_copy_c(fixed_r()))
+    assert_equal_ref(m.fixed_c())
+    assert_equal_ref(m.fixed_r())
+    assert_equal_ref(m.fixed_copy_r(m.fixed_r()))
+    assert_equal_ref(m.fixed_copy_c(m.fixed_c()))
+    assert_equal_ref(m.fixed_copy_r(m.fixed_c()))
+    assert_equal_ref(m.fixed_copy_c(m.fixed_r()))
 
 
 def test_dense():
-    from pybind11_tests import dense_r, dense_c, dense_copy_r, dense_copy_c
-
-    assert_equal_ref(dense_r())
-    assert_equal_ref(dense_c())
-    assert_equal_ref(dense_copy_r(dense_r()))
-    assert_equal_ref(dense_copy_c(dense_c()))
-    assert_equal_ref(dense_copy_r(dense_c()))
-    assert_equal_ref(dense_copy_c(dense_r()))
+    assert_equal_ref(m.dense_r())
+    assert_equal_ref(m.dense_c())
+    assert_equal_ref(m.dense_copy_r(m.dense_r()))
+    assert_equal_ref(m.dense_copy_c(m.dense_c()))
+    assert_equal_ref(m.dense_copy_r(m.dense_c()))
+    assert_equal_ref(m.dense_copy_c(m.dense_r()))
 
 
 def test_partially_fixed():
-    from pybind11_tests import (partial_copy_four_rm_r, partial_copy_four_rm_c,
-                                partial_copy_four_cm_r, partial_copy_four_cm_c)
-
     ref2 = np.array([[0., 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15]])
-    np.testing.assert_array_equal(partial_copy_four_rm_r(ref2), ref2)
-    np.testing.assert_array_equal(partial_copy_four_rm_c(ref2), ref2)
-    np.testing.assert_array_equal(partial_copy_four_rm_r(ref2[:, 1]), ref2[:, [1]])
-    np.testing.assert_array_equal(partial_copy_four_rm_c(ref2[0, :]), ref2[[0], :])
-    np.testing.assert_array_equal(partial_copy_four_rm_r(ref2[:, (0, 2)]), ref2[:, (0, 2)])
+    np.testing.assert_array_equal(m.partial_copy_four_rm_r(ref2), ref2)
+    np.testing.assert_array_equal(m.partial_copy_four_rm_c(ref2), ref2)
+    np.testing.assert_array_equal(m.partial_copy_four_rm_r(ref2[:, 1]), ref2[:, [1]])
+    np.testing.assert_array_equal(m.partial_copy_four_rm_c(ref2[0, :]), ref2[[0], :])
+    np.testing.assert_array_equal(m.partial_copy_four_rm_r(ref2[:, (0, 2)]), ref2[:, (0, 2)])
     np.testing.assert_array_equal(
-        partial_copy_four_rm_c(ref2[(3, 1, 2), :]), ref2[(3, 1, 2), :])
+        m.partial_copy_four_rm_c(ref2[(3, 1, 2), :]), ref2[(3, 1, 2), :])
 
-    np.testing.assert_array_equal(partial_copy_four_cm_r(ref2), ref2)
-    np.testing.assert_array_equal(partial_copy_four_cm_c(ref2), ref2)
-    np.testing.assert_array_equal(partial_copy_four_cm_r(ref2[:, 1]), ref2[:, [1]])
-    np.testing.assert_array_equal(partial_copy_four_cm_c(ref2[0, :]), ref2[[0], :])
-    np.testing.assert_array_equal(partial_copy_four_cm_r(ref2[:, (0, 2)]), ref2[:, (0, 2)])
+    np.testing.assert_array_equal(m.partial_copy_four_cm_r(ref2), ref2)
+    np.testing.assert_array_equal(m.partial_copy_four_cm_c(ref2), ref2)
+    np.testing.assert_array_equal(m.partial_copy_four_cm_r(ref2[:, 1]), ref2[:, [1]])
+    np.testing.assert_array_equal(m.partial_copy_four_cm_c(ref2[0, :]), ref2[[0], :])
+    np.testing.assert_array_equal(m.partial_copy_four_cm_r(ref2[:, (0, 2)]), ref2[:, (0, 2)])
     np.testing.assert_array_equal(
-        partial_copy_four_cm_c(ref2[(3, 1, 2), :]), ref2[(3, 1, 2), :])
+        m.partial_copy_four_cm_c(ref2[(3, 1, 2), :]), ref2[(3, 1, 2), :])
+
+    # TypeError should be raise for a shape mismatch
+    functions = [m.partial_copy_four_rm_r, m.partial_copy_four_rm_c,
+                 m.partial_copy_four_cm_r, m.partial_copy_four_cm_c]
+    matrix_with_wrong_shape = [[1, 2],
+                               [3, 4]]
+    for f in functions:
+        with pytest.raises(TypeError) as excinfo:
+            f(matrix_with_wrong_shape)
+        assert "incompatible function arguments" in str(excinfo.value)
 
 
 def test_mutator_descriptors():
-    from pybind11_tests import fixed_mutator_r, fixed_mutator_c, fixed_mutator_a
     zr = np.arange(30, dtype='float32').reshape(5, 6)  # row-major
     zc = zr.reshape(6, 5).transpose()  # column-major
 
-    fixed_mutator_r(zr)
-    fixed_mutator_c(zc)
-    fixed_mutator_a(zr)
-    fixed_mutator_a(zc)
+    m.fixed_mutator_r(zr)
+    m.fixed_mutator_c(zc)
+    m.fixed_mutator_a(zr)
+    m.fixed_mutator_a(zc)
     with pytest.raises(TypeError) as excinfo:
-        fixed_mutator_r(zc)
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable, flags.c_contiguous]) -> arg0: None'
+        m.fixed_mutator_r(zc)
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable, flags.c_contiguous]) -> None'
             in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
-        fixed_mutator_c(zr)
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable, flags.f_contiguous]) -> arg0: None'
+        m.fixed_mutator_c(zr)
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable, flags.f_contiguous]) -> None'
             in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
-        fixed_mutator_a(np.array([[1, 2], [3, 4]], dtype='float32'))
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable]) -> arg0: None'
+        m.fixed_mutator_a(np.array([[1, 2], [3, 4]], dtype='float32'))
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable]) -> None'
             in str(excinfo.value))
     zr.flags.writeable = False
     with pytest.raises(TypeError):
-        fixed_mutator_r(zr)
+        m.fixed_mutator_r(zr)
     with pytest.raises(TypeError):
-        fixed_mutator_a(zr)
+        m.fixed_mutator_a(zr)
 
 
 def test_cpp_casting():
-    from pybind11_tests import (cpp_copy, cpp_ref_c, cpp_ref_r, cpp_ref_any,
-                                fixed_r, fixed_c, get_cm_ref, get_rm_ref, ReturnTester)
-    assert cpp_copy(fixed_r()) == 22.
-    assert cpp_copy(fixed_c()) == 22.
+    assert m.cpp_copy(m.fixed_r()) == 22.
+    assert m.cpp_copy(m.fixed_c()) == 22.
     z = np.array([[5., 6], [7, 8]])
-    assert cpp_copy(z) == 7.
-    assert cpp_copy(get_cm_ref()) == 21.
-    assert cpp_copy(get_rm_ref()) == 21.
-    assert cpp_ref_c(get_cm_ref()) == 21.
-    assert cpp_ref_r(get_rm_ref()) == 21.
+    assert m.cpp_copy(z) == 7.
+    assert m.cpp_copy(m.get_cm_ref()) == 21.
+    assert m.cpp_copy(m.get_rm_ref()) == 21.
+    assert m.cpp_ref_c(m.get_cm_ref()) == 21.
+    assert m.cpp_ref_r(m.get_rm_ref()) == 21.
     with pytest.raises(RuntimeError) as excinfo:
-        # Can't reference fixed_c: it contains floats, cpp_ref_any wants doubles
-        cpp_ref_any(fixed_c())
+        # Can't reference m.fixed_c: it contains floats, m.cpp_ref_any wants doubles
+        m.cpp_ref_any(m.fixed_c())
     assert 'Unable to cast Python instance' in str(excinfo.value)
     with pytest.raises(RuntimeError) as excinfo:
-        # Can't reference fixed_r: it contains floats, cpp_ref_any wants doubles
-        cpp_ref_any(fixed_r())
+        # Can't reference m.fixed_r: it contains floats, m.cpp_ref_any wants doubles
+        m.cpp_ref_any(m.fixed_r())
     assert 'Unable to cast Python instance' in str(excinfo.value)
-    assert cpp_ref_any(ReturnTester.create()) == 1.
+    assert m.cpp_ref_any(m.ReturnTester.create()) == 1.
 
-    assert cpp_ref_any(get_cm_ref()) == 21.
-    assert cpp_ref_any(get_cm_ref()) == 21.
+    assert m.cpp_ref_any(m.get_cm_ref()) == 21.
+    assert m.cpp_ref_any(m.get_cm_ref()) == 21.
 
 
 def test_pass_readonly_array():
-    from pybind11_tests import fixed_copy_r, fixed_r, fixed_r_const
     z = np.full((5, 6), 42.0)
     z.flags.writeable = False
-    np.testing.assert_array_equal(z, fixed_copy_r(z))
-    np.testing.assert_array_equal(fixed_r_const(), fixed_r())
-    assert not fixed_r_const().flags.writeable
-    np.testing.assert_array_equal(fixed_copy_r(fixed_r_const()), fixed_r_const())
+    np.testing.assert_array_equal(z, m.fixed_copy_r(z))
+    np.testing.assert_array_equal(m.fixed_r_const(), m.fixed_r())
+    assert not m.fixed_r_const().flags.writeable
+    np.testing.assert_array_equal(m.fixed_copy_r(m.fixed_r_const()), m.fixed_r_const())
 
 
 def test_nonunit_stride_from_python():
-    from pybind11_tests import (
-        double_row, double_col, double_complex, double_mat_cm, double_mat_rm,
-        double_threec, double_threer)
-
     counting_mat = np.arange(9.0, dtype=np.float32).reshape((3, 3))
     second_row = counting_mat[1, :]
     second_col = counting_mat[:, 1]
-    np.testing.assert_array_equal(double_row(second_row), 2.0 * second_row)
-    np.testing.assert_array_equal(double_col(second_row), 2.0 * second_row)
-    np.testing.assert_array_equal(double_complex(second_row), 2.0 * second_row)
-    np.testing.assert_array_equal(double_row(second_col), 2.0 * second_col)
-    np.testing.assert_array_equal(double_col(second_col), 2.0 * second_col)
-    np.testing.assert_array_equal(double_complex(second_col), 2.0 * second_col)
+    np.testing.assert_array_equal(m.double_row(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_col(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_complex(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_row(second_col), 2.0 * second_col)
+    np.testing.assert_array_equal(m.double_col(second_col), 2.0 * second_col)
+    np.testing.assert_array_equal(m.double_complex(second_col), 2.0 * second_col)
 
     counting_3d = np.arange(27.0, dtype=np.float32).reshape((3, 3, 3))
     slices = [counting_3d[0, :, :], counting_3d[:, 0, :], counting_3d[:, :, 0]]
     for slice_idx, ref_mat in enumerate(slices):
-        np.testing.assert_array_equal(double_mat_cm(ref_mat), 2.0 * ref_mat)
-        np.testing.assert_array_equal(double_mat_rm(ref_mat), 2.0 * ref_mat)
+        np.testing.assert_array_equal(m.double_mat_cm(ref_mat), 2.0 * ref_mat)
+        np.testing.assert_array_equal(m.double_mat_rm(ref_mat), 2.0 * ref_mat)
 
     # Mutator:
-    double_threer(second_row)
-    double_threec(second_col)
+    m.double_threer(second_row)
+    m.double_threec(second_col)
     np.testing.assert_array_equal(counting_mat, [[0., 2, 2], [6, 16, 10], [6, 14, 8]])
 
 
-def test_nonunit_stride_to_python():
-    from pybind11_tests import diagonal, diagonal_1, diagonal_n, block
+def test_negative_stride_from_python(msg):
+    """Eigen doesn't support (as of yet) negative strides. When a function takes an Eigen matrix by
+    copy or const reference, we can pass a numpy array that has negative strides.  Otherwise, an
+    exception will be thrown as Eigen will not be able to map the numpy array."""
+
+    counting_mat = np.arange(9.0, dtype=np.float32).reshape((3, 3))
+    counting_mat = counting_mat[::-1, ::-1]
+    second_row = counting_mat[1, :]
+    second_col = counting_mat[:, 1]
+    np.testing.assert_array_equal(m.double_row(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_col(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_complex(second_row), 2.0 * second_row)
+    np.testing.assert_array_equal(m.double_row(second_col), 2.0 * second_col)
+    np.testing.assert_array_equal(m.double_col(second_col), 2.0 * second_col)
+    np.testing.assert_array_equal(m.double_complex(second_col), 2.0 * second_col)
+
+    counting_3d = np.arange(27.0, dtype=np.float32).reshape((3, 3, 3))
+    counting_3d = counting_3d[::-1, ::-1, ::-1]
+    slices = [counting_3d[0, :, :], counting_3d[:, 0, :], counting_3d[:, :, 0]]
+    for slice_idx, ref_mat in enumerate(slices):
+        np.testing.assert_array_equal(m.double_mat_cm(ref_mat), 2.0 * ref_mat)
+        np.testing.assert_array_equal(m.double_mat_rm(ref_mat), 2.0 * ref_mat)
+
+    # Mutator:
+    with pytest.raises(TypeError) as excinfo:
+        m.double_threer(second_row)
+    assert msg(excinfo.value) == """
+        double_threer(): incompatible function arguments. The following argument types are supported:
+            1. (arg0: numpy.ndarray[float32[1, 3], flags.writeable]) -> None
+
+        Invoked with: array([ 5.,  4.,  3.], dtype=float32)
+    """  # noqa: E501 line too long
+
+    with pytest.raises(TypeError) as excinfo:
+        m.double_threec(second_col)
+    assert msg(excinfo.value) == """
+        double_threec(): incompatible function arguments. The following argument types are supported:
+            1. (arg0: numpy.ndarray[float32[3, 1], flags.writeable]) -> None
+
+        Invoked with: array([ 7.,  4.,  1.], dtype=float32)
+    """  # noqa: E501 line too long
+
 
-    assert np.all(diagonal(ref) == ref.diagonal())
-    assert np.all(diagonal_1(ref) == ref.diagonal(1))
+def test_nonunit_stride_to_python():
+    assert np.all(m.diagonal(ref) == ref.diagonal())
+    assert np.all(m.diagonal_1(ref) == ref.diagonal(1))
     for i in range(-5, 7):
-        assert np.all(diagonal_n(ref, i) == ref.diagonal(i)), "diagonal_n({})".format(i)
+        assert np.all(m.diagonal_n(ref, i) == ref.diagonal(i)), "m.diagonal_n({})".format(i)
 
-    assert np.all(block(ref, 2, 1, 3, 3) == ref[2:5, 1:4])
-    assert np.all(block(ref, 1, 4, 4, 2) == ref[1:, 4:])
-    assert np.all(block(ref, 1, 4, 3, 2) == ref[1:4, 4:])
+    assert np.all(m.block(ref, 2, 1, 3, 3) == ref[2:5, 1:4])
+    assert np.all(m.block(ref, 1, 4, 4, 2) == ref[1:, 4:])
+    assert np.all(m.block(ref, 1, 4, 3, 2) == ref[1:4, 4:])
 
 
 def test_eigen_ref_to_python():
-    from pybind11_tests import cholesky1, cholesky2, cholesky3, cholesky4
-
-    chols = [cholesky1, cholesky2, cholesky3, cholesky4]
+    chols = [m.cholesky1, m.cholesky2, m.cholesky3, m.cholesky4]
     for i, chol in enumerate(chols, start=1):
         mymat = chol(np.array([[1., 2, 4], [2, 13, 23], [4, 23, 77]]))
         assert np.all(mymat == np.array([[1, 0, 0], [2, 3, 0], [4, 5, 6]])), "cholesky{}".format(i)
@@ -189,9 +225,9 @@ def array_copy_but_one(a, r, c, v):
 
 def test_eigen_return_references():
     """Tests various ways of returning references and non-referencing copies"""
-    from pybind11_tests import ReturnTester
+
     master = np.ones((10, 10))
-    a = ReturnTester()
+    a = m.ReturnTester()
     a_get1 = a.get()
     assert not a_get1.flags.owndata and a_get1.flags.writeable
     assign_both(a_get1, master, 3, 3, 5)
@@ -301,7 +337,6 @@ def test_eigen_return_references():
 
 
 def assert_keeps_alive(cl, method, *args):
-    from pybind11_tests import ConstructorStats
     cstats = ConstructorStats.get(cl)
     start_with = cstats.alive()
     a = cl()
@@ -317,10 +352,8 @@ def assert_keeps_alive(cl, method, *args):
 
 
 def test_eigen_keepalive():
-    from pybind11_tests import ReturnTester, ConstructorStats
-    a = ReturnTester()
-
-    cstats = ConstructorStats.get(ReturnTester)
+    a = m.ReturnTester()
+    cstats = ConstructorStats.get(m.ReturnTester)
     assert cstats.alive() == 1
     unsafe = [a.ref(), a.ref_const(), a.block(1, 2, 3, 4)]
     copies = [a.copy_get(), a.copy_view(), a.copy_ref(), a.copy_ref_const(),
@@ -330,43 +363,43 @@ def test_eigen_keepalive():
     del unsafe
     del copies
 
-    for meth in [ReturnTester.get, ReturnTester.get_ptr, ReturnTester.view,
-                 ReturnTester.view_ptr, ReturnTester.ref_safe, ReturnTester.ref_const_safe,
-                 ReturnTester.corners, ReturnTester.corners_const]:
-        assert_keeps_alive(ReturnTester, meth)
+    for meth in [m.ReturnTester.get, m.ReturnTester.get_ptr, m.ReturnTester.view,
+                 m.ReturnTester.view_ptr, m.ReturnTester.ref_safe, m.ReturnTester.ref_const_safe,
+                 m.ReturnTester.corners, m.ReturnTester.corners_const]:
+        assert_keeps_alive(m.ReturnTester, meth)
 
-    for meth in [ReturnTester.block_safe, ReturnTester.block_const]:
-        assert_keeps_alive(ReturnTester, meth, 4, 3, 2, 1)
+    for meth in [m.ReturnTester.block_safe, m.ReturnTester.block_const]:
+        assert_keeps_alive(m.ReturnTester, meth, 4, 3, 2, 1)
 
 
 def test_eigen_ref_mutators():
-    """Tests whether Eigen can mutate numpy values"""
-    from pybind11_tests import add_rm, add_cm, add_any, add1, add2
+    """Tests Eigen's ability to mutate numpy values"""
+
     orig = np.array([[1., 2, 3], [4, 5, 6], [7, 8, 9]])
     zr = np.array(orig)
     zc = np.array(orig, order='F')
-    add_rm(zr, 1, 0, 100)
+    m.add_rm(zr, 1, 0, 100)
     assert np.all(zr == np.array([[1., 2, 3], [104, 5, 6], [7, 8, 9]]))
-    add_cm(zc, 1, 0, 200)
+    m.add_cm(zc, 1, 0, 200)
     assert np.all(zc == np.array([[1., 2, 3], [204, 5, 6], [7, 8, 9]]))
 
-    add_any(zr, 1, 0, 20)
+    m.add_any(zr, 1, 0, 20)
     assert np.all(zr == np.array([[1., 2, 3], [124, 5, 6], [7, 8, 9]]))
-    add_any(zc, 1, 0, 10)
+    m.add_any(zc, 1, 0, 10)
     assert np.all(zc == np.array([[1., 2, 3], [214, 5, 6], [7, 8, 9]]))
 
     # Can't reference a col-major array with a row-major Ref, and vice versa:
     with pytest.raises(TypeError):
-        add_rm(zc, 1, 0, 1)
+        m.add_rm(zc, 1, 0, 1)
     with pytest.raises(TypeError):
-        add_cm(zr, 1, 0, 1)
+        m.add_cm(zr, 1, 0, 1)
 
     # Overloads:
-    add1(zr, 1, 0, -100)
-    add2(zr, 1, 0, -20)
+    m.add1(zr, 1, 0, -100)
+    m.add2(zr, 1, 0, -20)
     assert np.all(zr == orig)
-    add1(zc, 1, 0, -200)
-    add2(zc, 1, 0, -10)
+    m.add1(zc, 1, 0, -200)
+    m.add2(zc, 1, 0, -10)
     assert np.all(zc == orig)
 
     # a non-contiguous slice (this won't work on either the row- or
@@ -378,15 +411,15 @@ def test_eigen_ref_mutators():
     assert np.all(cornersc == np.array([[1., 3], [7, 9]]))
 
     with pytest.raises(TypeError):
-        add_rm(cornersr, 0, 1, 25)
+        m.add_rm(cornersr, 0, 1, 25)
     with pytest.raises(TypeError):
-        add_cm(cornersr, 0, 1, 25)
+        m.add_cm(cornersr, 0, 1, 25)
     with pytest.raises(TypeError):
-        add_rm(cornersc, 0, 1, 25)
+        m.add_rm(cornersc, 0, 1, 25)
     with pytest.raises(TypeError):
-        add_cm(cornersc, 0, 1, 25)
-    add_any(cornersr, 0, 1, 25)
-    add_any(cornersc, 0, 1, 44)
+        m.add_cm(cornersc, 0, 1, 25)
+    m.add_any(cornersr, 0, 1, 25)
+    m.add_any(cornersc, 0, 1, 44)
     assert np.all(zr == np.array([[1., 2, 28], [4, 5, 6], [7, 8, 9]]))
     assert np.all(zc == np.array([[1., 2, 47], [4, 5, 6], [7, 8, 9]]))
 
@@ -394,30 +427,29 @@ def test_eigen_ref_mutators():
     zro = zr[0:4, 0:4]
     zro.flags.writeable = False
     with pytest.raises(TypeError):
-        add_rm(zro, 0, 0, 0)
+        m.add_rm(zro, 0, 0, 0)
     with pytest.raises(TypeError):
-        add_any(zro, 0, 0, 0)
+        m.add_any(zro, 0, 0, 0)
     with pytest.raises(TypeError):
-        add1(zro, 0, 0, 0)
+        m.add1(zro, 0, 0, 0)
     with pytest.raises(TypeError):
-        add2(zro, 0, 0, 0)
+        m.add2(zro, 0, 0, 0)
 
     # integer array shouldn't be passable to a double-matrix-accepting mutating func:
     zi = np.array([[1, 2], [3, 4]])
     with pytest.raises(TypeError):
-        add_rm(zi)
+        m.add_rm(zi)
 
 
 def test_numpy_ref_mutators():
     """Tests numpy mutating Eigen matrices (for returned Eigen::Ref<...>s)"""
-    from pybind11_tests import (
-        get_cm_ref, get_cm_const_ref, get_rm_ref, get_rm_const_ref, reset_refs)
-    reset_refs()  # In case another test already changed it
 
-    zc = get_cm_ref()
-    zcro = get_cm_const_ref()
-    zr = get_rm_ref()
-    zrro = get_rm_const_ref()
+    m.reset_refs()  # In case another test already changed it
+
+    zc = m.get_cm_ref()
+    zcro = m.get_cm_const_ref()
+    zr = m.get_rm_ref()
+    zrro = m.get_rm_const_ref()
 
     assert [zc[1, 2], zcro[1, 2], zr[1, 2], zrro[1, 2]] == [23] * 4
 
@@ -431,12 +463,12 @@ def test_numpy_ref_mutators():
     # We should have just changed zc, of course, but also zcro and the original eigen matrix
     assert np.all(zc == expect)
     assert np.all(zcro == expect)
-    assert np.all(get_cm_ref() == expect)
+    assert np.all(m.get_cm_ref() == expect)
 
     zr[1, 2] = 99
     assert np.all(zr == expect)
     assert np.all(zrro == expect)
-    assert np.all(get_rm_ref() == expect)
+    assert np.all(m.get_rm_ref() == expect)
 
     # Make sure the readonly ones are numpy-readonly:
     with pytest.raises(ValueError):
@@ -446,7 +478,7 @@ def test_numpy_ref_mutators():
 
     # We should be able to explicitly copy like this (and since we're copying,
     # the const should drop away)
-    y1 = np.array(get_cm_const_ref())
+    y1 = np.array(m.get_cm_const_ref())
 
     assert y1.flags.owndata and y1.flags.writeable
     # We should get copies of the eigen data, which was modified above:
@@ -458,19 +490,18 @@ def test_numpy_ref_mutators():
 
 def test_both_ref_mutators():
     """Tests a complex chain of nested eigen/numpy references"""
-    from pybind11_tests import (
-        incr_matrix, get_cm_ref, incr_matrix_any, even_cols, even_rows, reset_refs)
-    reset_refs()  # In case another test already changed it
 
-    z = get_cm_ref()  # numpy -> eigen
+    m.reset_refs()  # In case another test already changed it
+
+    z = m.get_cm_ref()  # numpy -> eigen
     z[0, 2] -= 3
-    z2 = incr_matrix(z, 1)  # numpy -> eigen -> numpy -> eigen
+    z2 = m.incr_matrix(z, 1)  # numpy -> eigen -> numpy -> eigen
     z2[1, 1] += 6
-    z3 = incr_matrix(z, 2)  # (numpy -> eigen)^3
+    z3 = m.incr_matrix(z, 2)  # (numpy -> eigen)^3
     z3[2, 2] += -5
-    z4 = incr_matrix(z, 3)  # (numpy -> eigen)^4
+    z4 = m.incr_matrix(z, 3)  # (numpy -> eigen)^4
     z4[1, 1] -= 1
-    z5 = incr_matrix(z, 4)  # (numpy -> eigen)^5
+    z5 = m.incr_matrix(z, 4)  # (numpy -> eigen)^5
     z5[0, 0] = 0
     assert np.all(z == z2)
     assert np.all(z == z3)
@@ -480,11 +511,11 @@ def test_both_ref_mutators():
     assert np.all(z == expect)
 
     y = np.array(range(100), dtype='float64').reshape(10, 10)
-    y2 = incr_matrix_any(y, 10)  # np -> eigen -> np
-    y3 = incr_matrix_any(y2[0::2, 0::2], -33)  # np -> eigen -> np slice -> np -> eigen -> np
-    y4 = even_rows(y3)  # numpy -> eigen slice -> (... y3)
-    y5 = even_cols(y4)  # numpy -> eigen slice -> (... y4)
-    y6 = incr_matrix_any(y5, 1000)  # numpy -> eigen -> (... y5)
+    y2 = m.incr_matrix_any(y, 10)  # np -> eigen -> np
+    y3 = m.incr_matrix_any(y2[0::2, 0::2], -33)  # np -> eigen -> np slice -> np -> eigen -> np
+    y4 = m.even_rows(y3)  # numpy -> eigen slice -> (... y3)
+    y5 = m.even_cols(y4)  # numpy -> eigen slice -> (... y4)
+    y6 = m.incr_matrix_any(y5, 1000)  # numpy -> eigen -> (... y5)
 
     # Apply same mutations using just numpy:
     yexpect = np.array(range(100), dtype='float64').reshape(10, 10)
@@ -500,7 +531,6 @@ def test_both_ref_mutators():
 
 
 def test_nocopy_wrapper():
-    from pybind11_tests import get_elem, get_elem_nocopy, get_elem_rm_nocopy
     # get_elem requires a column-contiguous matrix reference, but should be
     # callable with other types of matrix (via copying):
     int_matrix_colmajor = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], order='F')
@@ -509,46 +539,58 @@ def test_nocopy_wrapper():
     dbl_matrix_rowmajor = np.array(int_matrix_rowmajor, dtype='double', order='C', copy=True)
 
     # All should be callable via get_elem:
-    assert get_elem(int_matrix_colmajor) == 8
-    assert get_elem(dbl_matrix_colmajor) == 8
-    assert get_elem(int_matrix_rowmajor) == 8
-    assert get_elem(dbl_matrix_rowmajor) == 8
+    assert m.get_elem(int_matrix_colmajor) == 8
+    assert m.get_elem(dbl_matrix_colmajor) == 8
+    assert m.get_elem(int_matrix_rowmajor) == 8
+    assert m.get_elem(dbl_matrix_rowmajor) == 8
 
-    # All but the second should fail with get_elem_nocopy:
+    # All but the second should fail with m.get_elem_nocopy:
     with pytest.raises(TypeError) as excinfo:
-        get_elem_nocopy(int_matrix_colmajor)
+        m.get_elem_nocopy(int_matrix_colmajor)
     assert ('get_elem_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.f_contiguous' in str(excinfo.value))
-    assert get_elem_nocopy(dbl_matrix_colmajor) == 8
+    assert m.get_elem_nocopy(dbl_matrix_colmajor) == 8
     with pytest.raises(TypeError) as excinfo:
-        get_elem_nocopy(int_matrix_rowmajor)
+        m.get_elem_nocopy(int_matrix_rowmajor)
     assert ('get_elem_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.f_contiguous' in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
-        get_elem_nocopy(dbl_matrix_rowmajor)
+        m.get_elem_nocopy(dbl_matrix_rowmajor)
     assert ('get_elem_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.f_contiguous' in str(excinfo.value))
 
     # For the row-major test, we take a long matrix in row-major, so only the third is allowed:
     with pytest.raises(TypeError) as excinfo:
-        get_elem_rm_nocopy(int_matrix_colmajor)
+        m.get_elem_rm_nocopy(int_matrix_colmajor)
     assert ('get_elem_rm_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.c_contiguous' in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
-        get_elem_rm_nocopy(dbl_matrix_colmajor)
+        m.get_elem_rm_nocopy(dbl_matrix_colmajor)
     assert ('get_elem_rm_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.c_contiguous' in str(excinfo.value))
-    assert get_elem_rm_nocopy(int_matrix_rowmajor) == 8
+    assert m.get_elem_rm_nocopy(int_matrix_rowmajor) == 8
     with pytest.raises(TypeError) as excinfo:
-        get_elem_rm_nocopy(dbl_matrix_rowmajor)
+        m.get_elem_rm_nocopy(dbl_matrix_rowmajor)
     assert ('get_elem_rm_nocopy(): incompatible function arguments.' in str(excinfo.value) and
             ', flags.c_contiguous' in str(excinfo.value))
 
 
-def test_special_matrix_objects():
-    from pybind11_tests import incr_diag, symmetric_upper, symmetric_lower
+def test_eigen_ref_life_support():
+    """Ensure the lifetime of temporary arrays created by the `Ref` caster
+
+    The `Ref` caster sometimes creates a copy which needs to stay alive. This needs to
+    happen both for directs casts (just the array) or indirectly (e.g. list of arrays).
+    """
+
+    a = np.full(shape=10, fill_value=8, dtype=np.int8)
+    assert m.get_elem_direct(a) == 8
+
+    list_of_a = [a]
+    assert m.get_elem_indirect(list_of_a) == 8
 
-    assert np.all(incr_diag(7) == np.diag([1., 2, 3, 4, 5, 6, 7]))
+
+def test_special_matrix_objects():
+    assert np.all(m.incr_diag(7) == np.diag([1., 2, 3, 4, 5, 6, 7]))
 
     asymm = np.array([[ 1.,  2,  3,  4],
                       [ 5,  6,  7,  8],
@@ -561,66 +603,79 @@ def test_special_matrix_objects():
             symm_lower[i, j] = symm_lower[j, i]
             symm_upper[j, i] = symm_upper[i, j]
 
-    assert np.all(symmetric_lower(asymm) == symm_lower)
-    assert np.all(symmetric_upper(asymm) == symm_upper)
+    assert np.all(m.symmetric_lower(asymm) == symm_lower)
+    assert np.all(m.symmetric_upper(asymm) == symm_upper)
 
 
 def test_dense_signature(doc):
-    from pybind11_tests import double_col, double_row, double_complex, double_mat_rm
-
-    assert doc(double_col) == """
+    assert doc(m.double_col) == """
         double_col(arg0: numpy.ndarray[float32[m, 1]]) -> numpy.ndarray[float32[m, 1]]
     """
-    assert doc(double_row) == """
+    assert doc(m.double_row) == """
         double_row(arg0: numpy.ndarray[float32[1, n]]) -> numpy.ndarray[float32[1, n]]
     """
-    assert doc(double_complex) == """
+    assert doc(m.double_complex) == """
         double_complex(arg0: numpy.ndarray[complex64[m, 1]]) -> numpy.ndarray[complex64[m, 1]]
     """
-    assert doc(double_mat_rm) == """
+    assert doc(m.double_mat_rm) == """
         double_mat_rm(arg0: numpy.ndarray[float32[m, n]]) -> numpy.ndarray[float32[m, n]]
     """
 
 
+def test_named_arguments():
+    a = np.array([[1.0, 2], [3, 4], [5, 6]])
+    b = np.ones((2, 1))
+
+    assert np.all(m.matrix_multiply(a, b) == np.array([[3.], [7], [11]]))
+    assert np.all(m.matrix_multiply(A=a, B=b) == np.array([[3.], [7], [11]]))
+    assert np.all(m.matrix_multiply(B=b, A=a) == np.array([[3.], [7], [11]]))
+
+    with pytest.raises(ValueError) as excinfo:
+        m.matrix_multiply(b, a)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+    with pytest.raises(ValueError) as excinfo:
+        m.matrix_multiply(A=b, B=a)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+    with pytest.raises(ValueError) as excinfo:
+        m.matrix_multiply(B=a, A=b)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+
 @pytest.requires_eigen_and_scipy
 def test_sparse():
-    from pybind11_tests import sparse_r, sparse_c, sparse_copy_r, sparse_copy_c
-
-    assert_sparse_equal_ref(sparse_r())
-    assert_sparse_equal_ref(sparse_c())
-    assert_sparse_equal_ref(sparse_copy_r(sparse_r()))
-    assert_sparse_equal_ref(sparse_copy_c(sparse_c()))
-    assert_sparse_equal_ref(sparse_copy_r(sparse_c()))
-    assert_sparse_equal_ref(sparse_copy_c(sparse_r()))
+    assert_sparse_equal_ref(m.sparse_r())
+    assert_sparse_equal_ref(m.sparse_c())
+    assert_sparse_equal_ref(m.sparse_copy_r(m.sparse_r()))
+    assert_sparse_equal_ref(m.sparse_copy_c(m.sparse_c()))
+    assert_sparse_equal_ref(m.sparse_copy_r(m.sparse_c()))
+    assert_sparse_equal_ref(m.sparse_copy_c(m.sparse_r()))
 
 
 @pytest.requires_eigen_and_scipy
 def test_sparse_signature(doc):
-    from pybind11_tests import sparse_copy_r, sparse_copy_c
-
-    assert doc(sparse_copy_r) == """
+    assert doc(m.sparse_copy_r) == """
         sparse_copy_r(arg0: scipy.sparse.csr_matrix[float32]) -> scipy.sparse.csr_matrix[float32]
     """  # noqa: E501 line too long
-    assert doc(sparse_copy_c) == """
+    assert doc(m.sparse_copy_c) == """
         sparse_copy_c(arg0: scipy.sparse.csc_matrix[float32]) -> scipy.sparse.csc_matrix[float32]
     """  # noqa: E501 line too long
 
 
 def test_issue738():
-    from pybind11_tests import iss738_f1, iss738_f2
-
-    assert np.all(iss738_f1(np.array([[1., 2, 3]])) == np.array([[1., 102, 203]]))
-    assert np.all(iss738_f1(np.array([[1.], [2], [3]])) == np.array([[1.], [12], [23]]))
+    """Ignore strides on a length-1 dimension (even if they would be incompatible length > 1)"""
+    assert np.all(m.iss738_f1(np.array([[1., 2, 3]])) == np.array([[1., 102, 203]]))
+    assert np.all(m.iss738_f1(np.array([[1.], [2], [3]])) == np.array([[1.], [12], [23]]))
 
-    assert np.all(iss738_f2(np.array([[1., 2, 3]])) == np.array([[1., 102, 203]]))
-    assert np.all(iss738_f2(np.array([[1.], [2], [3]])) == np.array([[1.], [12], [23]]))
+    assert np.all(m.iss738_f2(np.array([[1., 2, 3]])) == np.array([[1., 102, 203]]))
+    assert np.all(m.iss738_f2(np.array([[1.], [2], [3]])) == np.array([[1.], [12], [23]]))
 
 
 def test_custom_operator_new():
     """Using Eigen types as member variables requires a class-specific
     operator new with proper alignment"""
-    from pybind11_tests import CustomOperatorNew
 
-    o = CustomOperatorNew()
+    o = m.CustomOperatorNew()
     np.testing.assert_allclose(o.a, 0.0)
     np.testing.assert_allclose(o.b.diagonal(), 1.0)
diff --git a/ext/pybind11/tests/test_embed/CMakeLists.txt b/ext/pybind11/tests/test_embed/CMakeLists.txt
new file mode 100644
index 000000000..0a43e0e22
--- /dev/null
+++ b/ext/pybind11/tests/test_embed/CMakeLists.txt
@@ -0,0 +1,34 @@
+if(${PYTHON_MODULE_EXTENSION} MATCHES "pypy")
+  add_custom_target(cpptest)  # Dummy target on PyPy. Embedding is not supported.
+  set(_suppress_unused_variable_warning "${DOWNLOAD_CATCH}")
+  return()
+endif()
+
+find_package(Catch 1.9.3)
+if(NOT CATCH_FOUND)
+  message(STATUS "Catch not detected. Interpreter tests will be skipped. Install Catch headers"
+                 " manually or use `cmake -DDOWNLOAD_CATCH=1` to fetch them automatically.")
+  return()
+endif()
+
+add_executable(test_embed
+  catch.cpp
+  test_interpreter.cpp
+)
+target_include_directories(test_embed PRIVATE ${CATCH_INCLUDE_DIR})
+pybind11_enable_warnings(test_embed)
+
+if(NOT CMAKE_VERSION VERSION_LESS 3.0)
+  target_link_libraries(test_embed PRIVATE pybind11::embed)
+else()
+  target_include_directories(test_embed PRIVATE ${PYBIND11_INCLUDE_DIR} ${PYTHON_INCLUDE_DIRS})
+  target_compile_options(test_embed PRIVATE ${PYBIND11_CPP_STANDARD})
+  target_link_libraries(test_embed PRIVATE ${PYTHON_LIBRARIES})
+endif()
+
+find_package(Threads REQUIRED)
+target_link_libraries(test_embed PUBLIC ${CMAKE_THREAD_LIBS_INIT})
+
+add_custom_target(cpptest COMMAND $<TARGET_FILE:test_embed>
+                  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+add_dependencies(check cpptest)
diff --git a/ext/pybind11/tests/test_embed/catch.cpp b/ext/pybind11/tests/test_embed/catch.cpp
new file mode 100644
index 000000000..cface485d
--- /dev/null
+++ b/ext/pybind11/tests/test_embed/catch.cpp
@@ -0,0 +1,16 @@
+// The Catch implementation is compiled here. This is a standalone
+// translation unit to avoid recompiling it for every test change.
+
+#include <pybind11/embed.h>
+
+#define CATCH_CONFIG_RUNNER
+#include <catch.hpp>
+
+namespace py = pybind11;
+
+int main(int argc, const char *argv[]) {
+    py::scoped_interpreter guard{};
+    auto result = Catch::Session().run(argc, argv);
+
+    return result < 0xff ? result : 0xff;
+}
diff --git a/ext/pybind11/tests/test_embed/test_interpreter.cpp b/ext/pybind11/tests/test_embed/test_interpreter.cpp
new file mode 100644
index 000000000..6b5f051f2
--- /dev/null
+++ b/ext/pybind11/tests/test_embed/test_interpreter.cpp
@@ -0,0 +1,269 @@
+#include <pybind11/embed.h>
+#include <catch.hpp>
+
+#include <thread>
+#include <fstream>
+#include <functional>
+
+namespace py = pybind11;
+using namespace py::literals;
+
+class Widget {
+public:
+    Widget(std::string message) : message(message) { }
+    virtual ~Widget() = default;
+
+    std::string the_message() const { return message; }
+    virtual int the_answer() const = 0;
+
+private:
+    std::string message;
+};
+
+class PyWidget final : public Widget {
+    using Widget::Widget;
+
+    int the_answer() const override { PYBIND11_OVERLOAD_PURE(int, Widget, the_answer); }
+};
+
+PYBIND11_EMBEDDED_MODULE(widget_module, m) {
+    py::class_<Widget, PyWidget>(m, "Widget")
+        .def(py::init<std::string>())
+        .def_property_readonly("the_message", &Widget::the_message);
+
+    m.def("add", [](int i, int j) { return i + j; });
+}
+
+PYBIND11_EMBEDDED_MODULE(throw_exception, ) {
+    throw std::runtime_error("C++ Error");
+}
+
+PYBIND11_EMBEDDED_MODULE(throw_error_already_set, ) {
+    auto d = py::dict();
+    d["missing"].cast<py::object>();
+}
+
+TEST_CASE("Pass classes and data between modules defined in C++ and Python") {
+    auto module = py::module::import("test_interpreter");
+    REQUIRE(py::hasattr(module, "DerivedWidget"));
+
+    auto locals = py::dict("hello"_a="Hello, World!", "x"_a=5, **module.attr("__dict__"));
+    py::exec(R"(
+        widget = DerivedWidget("{} - {}".format(hello, x))
+        message = widget.the_message
+    )", py::globals(), locals);
+    REQUIRE(locals["message"].cast<std::string>() == "Hello, World! - 5");
+
+    auto py_widget = module.attr("DerivedWidget")("The question");
+    auto message = py_widget.attr("the_message");
+    REQUIRE(message.cast<std::string>() == "The question");
+
+    const auto &cpp_widget = py_widget.cast<const Widget &>();
+    REQUIRE(cpp_widget.the_answer() == 42);
+}
+
+TEST_CASE("Import error handling") {
+    REQUIRE_NOTHROW(py::module::import("widget_module"));
+    REQUIRE_THROWS_WITH(py::module::import("throw_exception"),
+                        "ImportError: C++ Error");
+    REQUIRE_THROWS_WITH(py::module::import("throw_error_already_set"),
+                        Catch::Contains("ImportError: KeyError"));
+}
+
+TEST_CASE("There can be only one interpreter") {
+    static_assert(std::is_move_constructible<py::scoped_interpreter>::value, "");
+    static_assert(!std::is_move_assignable<py::scoped_interpreter>::value, "");
+    static_assert(!std::is_copy_constructible<py::scoped_interpreter>::value, "");
+    static_assert(!std::is_copy_assignable<py::scoped_interpreter>::value, "");
+
+    REQUIRE_THROWS_WITH(py::initialize_interpreter(), "The interpreter is already running");
+    REQUIRE_THROWS_WITH(py::scoped_interpreter(), "The interpreter is already running");
+
+    py::finalize_interpreter();
+    REQUIRE_NOTHROW(py::scoped_interpreter());
+    {
+        auto pyi1 = py::scoped_interpreter();
+        auto pyi2 = std::move(pyi1);
+    }
+    py::initialize_interpreter();
+}
+
+bool has_pybind11_internals_builtin() {
+    auto builtins = py::handle(PyEval_GetBuiltins());
+    return builtins.contains(PYBIND11_INTERNALS_ID);
+};
+
+bool has_pybind11_internals_static() {
+    return py::detail::get_internals_ptr() != nullptr;
+}
+
+TEST_CASE("Restart the interpreter") {
+    // Verify pre-restart state.
+    REQUIRE(py::module::import("widget_module").attr("add")(1, 2).cast<int>() == 3);
+    REQUIRE(has_pybind11_internals_builtin());
+    REQUIRE(has_pybind11_internals_static());
+
+    // Restart the interpreter.
+    py::finalize_interpreter();
+    REQUIRE(Py_IsInitialized() == 0);
+
+    py::initialize_interpreter();
+    REQUIRE(Py_IsInitialized() == 1);
+
+    // Internals are deleted after a restart.
+    REQUIRE_FALSE(has_pybind11_internals_builtin());
+    REQUIRE_FALSE(has_pybind11_internals_static());
+    pybind11::detail::get_internals();
+    REQUIRE(has_pybind11_internals_builtin());
+    REQUIRE(has_pybind11_internals_static());
+
+    // Make sure that an interpreter with no get_internals() created until finalize still gets the
+    // internals destroyed
+    py::finalize_interpreter();
+    py::initialize_interpreter();
+    bool ran = false;
+    py::module::import("__main__").attr("internals_destroy_test") =
+        py::capsule(&ran, [](void *ran) { py::detail::get_internals(); *static_cast<bool *>(ran) = true; });
+    REQUIRE_FALSE(has_pybind11_internals_builtin());
+    REQUIRE_FALSE(has_pybind11_internals_static());
+    REQUIRE_FALSE(ran);
+    py::finalize_interpreter();
+    REQUIRE(ran);
+    py::initialize_interpreter();
+    REQUIRE_FALSE(has_pybind11_internals_builtin());
+    REQUIRE_FALSE(has_pybind11_internals_static());
+
+    // C++ modules can be reloaded.
+    auto cpp_module = py::module::import("widget_module");
+    REQUIRE(cpp_module.attr("add")(1, 2).cast<int>() == 3);
+
+    // C++ type information is reloaded and can be used in python modules.
+    auto py_module = py::module::import("test_interpreter");
+    auto py_widget = py_module.attr("DerivedWidget")("Hello after restart");
+    REQUIRE(py_widget.attr("the_message").cast<std::string>() == "Hello after restart");
+}
+
+TEST_CASE("Subinterpreter") {
+    // Add tags to the modules in the main interpreter and test the basics.
+    py::module::import("__main__").attr("main_tag") = "main interpreter";
+    {
+        auto m = py::module::import("widget_module");
+        m.attr("extension_module_tag") = "added to module in main interpreter";
+
+        REQUIRE(m.attr("add")(1, 2).cast<int>() == 3);
+    }
+    REQUIRE(has_pybind11_internals_builtin());
+    REQUIRE(has_pybind11_internals_static());
+
+    /// Create and switch to a subinterpreter.
+    auto main_tstate = PyThreadState_Get();
+    auto sub_tstate = Py_NewInterpreter();
+
+    // Subinterpreters get their own copy of builtins. detail::get_internals() still
+    // works by returning from the static variable, i.e. all interpreters share a single
+    // global pybind11::internals;
+    REQUIRE_FALSE(has_pybind11_internals_builtin());
+    REQUIRE(has_pybind11_internals_static());
+
+    // Modules tags should be gone.
+    REQUIRE_FALSE(py::hasattr(py::module::import("__main__"), "tag"));
+    {
+        auto m = py::module::import("widget_module");
+        REQUIRE_FALSE(py::hasattr(m, "extension_module_tag"));
+
+        // Function bindings should still work.
+        REQUIRE(m.attr("add")(1, 2).cast<int>() == 3);
+    }
+
+    // Restore main interpreter.
+    Py_EndInterpreter(sub_tstate);
+    PyThreadState_Swap(main_tstate);
+
+    REQUIRE(py::hasattr(py::module::import("__main__"), "main_tag"));
+    REQUIRE(py::hasattr(py::module::import("widget_module"), "extension_module_tag"));
+}
+
+TEST_CASE("Execution frame") {
+    // When the interpreter is embedded, there is no execution frame, but `py::exec`
+    // should still function by using reasonable globals: `__main__.__dict__`.
+    py::exec("var = dict(number=42)");
+    REQUIRE(py::globals()["var"]["number"].cast<int>() == 42);
+}
+
+TEST_CASE("Threads") {
+    // Restart interpreter to ensure threads are not initialized
+    py::finalize_interpreter();
+    py::initialize_interpreter();
+    REQUIRE_FALSE(has_pybind11_internals_static());
+
+    constexpr auto num_threads = 10;
+    auto locals = py::dict("count"_a=0);
+
+    {
+        py::gil_scoped_release gil_release{};
+        REQUIRE(has_pybind11_internals_static());
+
+        auto threads = std::vector<std::thread>();
+        for (auto i = 0; i < num_threads; ++i) {
+            threads.emplace_back([&]() {
+                py::gil_scoped_acquire gil{};
+                locals["count"] = locals["count"].cast<int>() + 1;
+            });
+        }
+
+        for (auto &thread : threads) {
+            thread.join();
+        }
+    }
+
+    REQUIRE(locals["count"].cast<int>() == num_threads);
+}
+
+// Scope exit utility https://stackoverflow.com/a/36644501/7255855
+struct scope_exit {
+    std::function<void()> f_;
+    explicit scope_exit(std::function<void()> f) noexcept : f_(std::move(f)) {}
+    ~scope_exit() { if (f_) f_(); }
+};
+
+TEST_CASE("Reload module from file") {
+    // Disable generation of cached bytecode (.pyc files) for this test, otherwise
+    // Python might pick up an old version from the cache instead of the new versions
+    // of the .py files generated below
+    auto sys = py::module::import("sys");
+    bool dont_write_bytecode = sys.attr("dont_write_bytecode").cast<bool>();
+    sys.attr("dont_write_bytecode") = true;
+    // Reset the value at scope exit
+    scope_exit reset_dont_write_bytecode([&]() {
+        sys.attr("dont_write_bytecode") = dont_write_bytecode;
+    });
+
+    std::string module_name = "test_module_reload";
+    std::string module_file = module_name + ".py";
+
+    // Create the module .py file
+    std::ofstream test_module(module_file);
+    test_module << "def test():\n";
+    test_module << "    return 1\n";
+    test_module.close();
+    // Delete the file at scope exit
+    scope_exit delete_module_file([&]() {
+        std::remove(module_file.c_str());
+    });
+
+    // Import the module from file
+    auto module = py::module::import(module_name.c_str());
+    int result = module.attr("test")().cast<int>();
+    REQUIRE(result == 1);
+
+    // Update the module .py file with a small change
+    test_module.open(module_file);
+    test_module << "def test():\n";
+    test_module << "    return 2\n";
+    test_module.close();
+
+    // Reload the module
+    module.reload();
+    result = module.attr("test")().cast<int>();
+    REQUIRE(result == 2);
+}
diff --git a/ext/pybind11/tests/test_embed/test_interpreter.py b/ext/pybind11/tests/test_embed/test_interpreter.py
new file mode 100644
index 000000000..26a047921
--- /dev/null
+++ b/ext/pybind11/tests/test_embed/test_interpreter.py
@@ -0,0 +1,9 @@
+from widget_module import Widget
+
+
+class DerivedWidget(Widget):
+    def __init__(self, message):
+        super(DerivedWidget, self).__init__(message)
+
+    def the_answer(self):
+        return 42
diff --git a/ext/pybind11/tests/test_enum.cpp b/ext/pybind11/tests/test_enum.cpp
index 09f334cdb..49f31ba1f 100644
--- a/ext/pybind11/tests/test_enum.cpp
+++ b/ext/pybind11/tests/test_enum.cpp
@@ -9,60 +9,63 @@
 
 #include "pybind11_tests.h"
 
-enum UnscopedEnum {
-    EOne = 1,
-    ETwo
-};
-
-enum class ScopedEnum {
-    Two = 2,
-    Three
-};
-
-enum Flags {
-    Read = 4,
-    Write = 2,
-    Execute = 1
-};
-
-class ClassWithUnscopedEnum {
-public:
-    enum EMode {
-        EFirstMode = 1,
-        ESecondMode
+TEST_SUBMODULE(enums, m) {
+    // test_unscoped_enum
+    enum UnscopedEnum {
+        EOne = 1,
+        ETwo
     };
-
-    static EMode test_function(EMode mode) {
-        return mode;
-    }
-};
-
-std::string test_scoped_enum(ScopedEnum z) {
-    return "ScopedEnum::" + std::string(z == ScopedEnum::Two ? "Two" : "Three");
-}
-
-test_initializer enums([](py::module &m) {
-    m.def("test_scoped_enum", &test_scoped_enum);
-
     py::enum_<UnscopedEnum>(m, "UnscopedEnum", py::arithmetic())
         .value("EOne", EOne)
         .value("ETwo", ETwo)
         .export_values();
 
+    // test_scoped_enum
+    enum class ScopedEnum {
+        Two = 2,
+        Three
+    };
     py::enum_<ScopedEnum>(m, "ScopedEnum", py::arithmetic())
         .value("Two", ScopedEnum::Two)
         .value("Three", ScopedEnum::Three);
 
+    m.def("test_scoped_enum", [](ScopedEnum z) {
+        return "ScopedEnum::" + std::string(z == ScopedEnum::Two ? "Two" : "Three");
+    });
+
+    // test_binary_operators
+    enum Flags {
+        Read = 4,
+        Write = 2,
+        Execute = 1
+    };
     py::enum_<Flags>(m, "Flags", py::arithmetic())
         .value("Read", Flags::Read)
         .value("Write", Flags::Write)
         .value("Execute", Flags::Execute)
         .export_values();
 
+    // test_implicit_conversion
+    class ClassWithUnscopedEnum {
+    public:
+        enum EMode {
+            EFirstMode = 1,
+            ESecondMode
+        };
+
+        static EMode test_function(EMode mode) {
+            return mode;
+        }
+    };
     py::class_<ClassWithUnscopedEnum> exenum_class(m, "ClassWithUnscopedEnum");
     exenum_class.def_static("test_function", &ClassWithUnscopedEnum::test_function);
     py::enum_<ClassWithUnscopedEnum::EMode>(exenum_class, "EMode")
         .value("EFirstMode", ClassWithUnscopedEnum::EFirstMode)
         .value("ESecondMode", ClassWithUnscopedEnum::ESecondMode)
         .export_values();
-});
+
+    // test_enum_to_int
+    m.def("test_enum_to_int", [](int) { });
+    m.def("test_enum_to_uint", [](uint32_t) { });
+    m.def("test_enum_to_long_long", [](long long) { });
+}
diff --git a/ext/pybind11/tests/test_enum.py b/ext/pybind11/tests/test_enum.py
index ba7e22ab0..d8eff5278 100644
--- a/ext/pybind11/tests/test_enum.py
+++ b/ext/pybind11/tests/test_enum.py
@@ -1,51 +1,50 @@
 import pytest
+from pybind11_tests import enums as m
 
 
 def test_unscoped_enum():
-    from pybind11_tests import UnscopedEnum, EOne
-
-    assert str(UnscopedEnum.EOne) == "UnscopedEnum.EOne"
-    assert str(UnscopedEnum.ETwo) == "UnscopedEnum.ETwo"
-    assert str(EOne) == "UnscopedEnum.EOne"
+    assert str(m.UnscopedEnum.EOne) == "UnscopedEnum.EOne"
+    assert str(m.UnscopedEnum.ETwo) == "UnscopedEnum.ETwo"
+    assert str(m.EOne) == "UnscopedEnum.EOne"
     # __members__ property
-    assert UnscopedEnum.__members__ == {"EOne": UnscopedEnum.EOne, "ETwo": UnscopedEnum.ETwo}
+    assert m.UnscopedEnum.__members__ == \
+        {"EOne": m.UnscopedEnum.EOne, "ETwo": m.UnscopedEnum.ETwo}
     # __members__ readonly
     with pytest.raises(AttributeError):
-        UnscopedEnum.__members__ = {}
+        m.UnscopedEnum.__members__ = {}
     # __members__ returns a copy
-    foo = UnscopedEnum.__members__
+    foo = m.UnscopedEnum.__members__
     foo["bar"] = "baz"
-    assert UnscopedEnum.__members__ == {"EOne": UnscopedEnum.EOne, "ETwo": UnscopedEnum.ETwo}
+    assert m.UnscopedEnum.__members__ == \
+        {"EOne": m.UnscopedEnum.EOne, "ETwo": m.UnscopedEnum.ETwo}
 
     # no TypeError exception for unscoped enum ==/!= int comparisons
-    y = UnscopedEnum.ETwo
+    y = m.UnscopedEnum.ETwo
     assert y == 2
     assert y != 3
 
-    assert int(UnscopedEnum.ETwo) == 2
-    assert str(UnscopedEnum(2)) == "UnscopedEnum.ETwo"
+    assert int(m.UnscopedEnum.ETwo) == 2
+    assert str(m.UnscopedEnum(2)) == "UnscopedEnum.ETwo"
 
     # order
-    assert UnscopedEnum.EOne < UnscopedEnum.ETwo
-    assert UnscopedEnum.EOne < 2
-    assert UnscopedEnum.ETwo > UnscopedEnum.EOne
-    assert UnscopedEnum.ETwo > 1
-    assert UnscopedEnum.ETwo <= 2
-    assert UnscopedEnum.ETwo >= 2
-    assert UnscopedEnum.EOne <= UnscopedEnum.ETwo
-    assert UnscopedEnum.EOne <= 2
-    assert UnscopedEnum.ETwo >= UnscopedEnum.EOne
-    assert UnscopedEnum.ETwo >= 1
-    assert not (UnscopedEnum.ETwo < UnscopedEnum.EOne)
-    assert not (2 < UnscopedEnum.EOne)
+    assert m.UnscopedEnum.EOne < m.UnscopedEnum.ETwo
+    assert m.UnscopedEnum.EOne < 2
+    assert m.UnscopedEnum.ETwo > m.UnscopedEnum.EOne
+    assert m.UnscopedEnum.ETwo > 1
+    assert m.UnscopedEnum.ETwo <= 2
+    assert m.UnscopedEnum.ETwo >= 2
+    assert m.UnscopedEnum.EOne <= m.UnscopedEnum.ETwo
+    assert m.UnscopedEnum.EOne <= 2
+    assert m.UnscopedEnum.ETwo >= m.UnscopedEnum.EOne
+    assert m.UnscopedEnum.ETwo >= 1
+    assert not (m.UnscopedEnum.ETwo < m.UnscopedEnum.EOne)
+    assert not (2 < m.UnscopedEnum.EOne)
 
 
 def test_scoped_enum():
-    from pybind11_tests import ScopedEnum, test_scoped_enum
-
-    assert test_scoped_enum(ScopedEnum.Three) == "ScopedEnum::Three"
-    z = ScopedEnum.Two
-    assert test_scoped_enum(z) == "ScopedEnum::Two"
+    assert m.test_scoped_enum(m.ScopedEnum.Three) == "ScopedEnum::Three"
+    z = m.ScopedEnum.Two
+    assert m.test_scoped_enum(z) == "ScopedEnum::Two"
 
     # expected TypeError exceptions for scoped enum ==/!= int comparisons
     with pytest.raises(TypeError):
@@ -54,23 +53,21 @@ def test_scoped_enum():
         assert z != 3
 
     # order
-    assert ScopedEnum.Two < ScopedEnum.Three
-    assert ScopedEnum.Three > ScopedEnum.Two
-    assert ScopedEnum.Two <= ScopedEnum.Three
-    assert ScopedEnum.Two <= ScopedEnum.Two
-    assert ScopedEnum.Two >= ScopedEnum.Two
-    assert ScopedEnum.Three >= ScopedEnum.Two
+    assert m.ScopedEnum.Two < m.ScopedEnum.Three
+    assert m.ScopedEnum.Three > m.ScopedEnum.Two
+    assert m.ScopedEnum.Two <= m.ScopedEnum.Three
+    assert m.ScopedEnum.Two <= m.ScopedEnum.Two
+    assert m.ScopedEnum.Two >= m.ScopedEnum.Two
+    assert m.ScopedEnum.Three >= m.ScopedEnum.Two
 
 
 def test_implicit_conversion():
-    from pybind11_tests import ClassWithUnscopedEnum
-
-    assert str(ClassWithUnscopedEnum.EMode.EFirstMode) == "EMode.EFirstMode"
-    assert str(ClassWithUnscopedEnum.EFirstMode) == "EMode.EFirstMode"
+    assert str(m.ClassWithUnscopedEnum.EMode.EFirstMode) == "EMode.EFirstMode"
+    assert str(m.ClassWithUnscopedEnum.EFirstMode) == "EMode.EFirstMode"
 
-    f = ClassWithUnscopedEnum.test_function
-    first = ClassWithUnscopedEnum.EFirstMode
-    second = ClassWithUnscopedEnum.ESecondMode
+    f = m.ClassWithUnscopedEnum.test_function
+    first = m.ClassWithUnscopedEnum.EFirstMode
+    second = m.ClassWithUnscopedEnum.ESecondMode
 
     assert f(first) == 1
 
@@ -95,23 +92,30 @@ def test_implicit_conversion():
 
 
 def test_binary_operators():
-    from pybind11_tests import Flags
-
-    assert int(Flags.Read) == 4
-    assert int(Flags.Write) == 2
-    assert int(Flags.Execute) == 1
-    assert int(Flags.Read | Flags.Write | Flags.Execute) == 7
-    assert int(Flags.Read | Flags.Write) == 6
-    assert int(Flags.Read | Flags.Execute) == 5
-    assert int(Flags.Write | Flags.Execute) == 3
-    assert int(Flags.Write | 1) == 3
-
-    state = Flags.Read | Flags.Write
-    assert (state & Flags.Read) != 0
-    assert (state & Flags.Write) != 0
-    assert (state & Flags.Execute) == 0
+    assert int(m.Flags.Read) == 4
+    assert int(m.Flags.Write) == 2
+    assert int(m.Flags.Execute) == 1
+    assert int(m.Flags.Read | m.Flags.Write | m.Flags.Execute) == 7
+    assert int(m.Flags.Read | m.Flags.Write) == 6
+    assert int(m.Flags.Read | m.Flags.Execute) == 5
+    assert int(m.Flags.Write | m.Flags.Execute) == 3
+    assert int(m.Flags.Write | 1) == 3
+
+    state = m.Flags.Read | m.Flags.Write
+    assert (state & m.Flags.Read) != 0
+    assert (state & m.Flags.Write) != 0
+    assert (state & m.Flags.Execute) == 0
     assert (state & 1) == 0
 
     state2 = ~state
     assert state2 == -7
     assert int(state ^ state2) == -1
+
+
+def test_enum_to_int():
+    m.test_enum_to_int(m.Flags.Read)
+    m.test_enum_to_int(m.ClassWithUnscopedEnum.EMode.EFirstMode)
+    m.test_enum_to_uint(m.Flags.Read)
+    m.test_enum_to_uint(m.ClassWithUnscopedEnum.EMode.EFirstMode)
+    m.test_enum_to_long_long(m.Flags.Read)
+    m.test_enum_to_long_long(m.ClassWithUnscopedEnum.EMode.EFirstMode)
diff --git a/ext/pybind11/tests/test_eval.cpp b/ext/pybind11/tests/test_eval.cpp
index ed4c226fe..e09482191 100644
--- a/ext/pybind11/tests/test_eval.cpp
+++ b/ext/pybind11/tests/test_eval.cpp
@@ -11,7 +11,9 @@
 #include <pybind11/eval.h>
 #include "pybind11_tests.h"
 
-test_initializer eval([](py::module &m) {
+TEST_SUBMODULE(eval_, m) {
+    // test_evals
+
     auto global = py::dict(py::module::import("__main__").attr("__dict__"));
 
     m.def("test_eval_statements", [global]() {
@@ -20,14 +22,24 @@ test_initializer eval([](py::module &m) {
             return 42;
         });
 
-        auto result = py::eval<py::eval_statements>(
-            "print('Hello World!');\n"
-            "x = call_test();",
+        // Regular string literal
+        py::exec(
+            "message = 'Hello World!'\n"
+            "x = call_test()",
             global, local
         );
+
+        // Multi-line raw string literal
+        py::exec(R"(
+            if x == 42:
+                print(message)
+            else:
+                raise RuntimeError
+            )", global, local
+        );
         auto x = local["x"].cast<int>();
 
-        return result == py::none() && x == 42;
+        return x == 42;
     });
 
     m.def("test_eval", [global]() {
@@ -45,7 +57,7 @@ test_initializer eval([](py::module &m) {
 
         auto result = py::eval<py::eval_single_statement>("x = call_test()", py::dict(), local);
         auto x = local["x"].cast<int>();
-        return result == py::none() && x == 42;
+        return result.is_none() && x == 42;
     });
 
     m.def("test_eval_file", [global](py::str filename) {
@@ -56,7 +68,7 @@ test_initializer eval([](py::module &m) {
         local["call_test2"] = py::cpp_function([&](int value) { val_out = value; });
 
         auto result = py::eval_file(filename, global, local);
-        return val_out == 43 && result == py::none();
+        return val_out == 43 && result.is_none();
     });
 
     m.def("test_eval_failure", []() {
@@ -76,4 +88,4 @@ test_initializer eval([](py::module &m) {
         }
         return false;
     });
-});
+}
diff --git a/ext/pybind11/tests/test_eval.py b/ext/pybind11/tests/test_eval.py
index 8715dbadb..bda4ef6bf 100644
--- a/ext/pybind11/tests/test_eval.py
+++ b/ext/pybind11/tests/test_eval.py
@@ -1,19 +1,17 @@
 import os
+from pybind11_tests import eval_ as m
 
 
 def test_evals(capture):
-    from pybind11_tests import (test_eval_statements, test_eval, test_eval_single_statement,
-                                test_eval_file, test_eval_failure, test_eval_file_failure)
-
     with capture:
-        assert test_eval_statements()
+        assert m.test_eval_statements()
     assert capture == "Hello World!"
 
-    assert test_eval()
-    assert test_eval_single_statement()
+    assert m.test_eval()
+    assert m.test_eval_single_statement()
 
     filename = os.path.join(os.path.dirname(__file__), "test_eval_call.py")
-    assert test_eval_file(filename)
+    assert m.test_eval_file(filename)
 
-    assert test_eval_failure()
-    assert test_eval_file_failure()
+    assert m.test_eval_failure()
+    assert m.test_eval_file_failure()
diff --git a/ext/pybind11/tests/test_exceptions.cpp b/ext/pybind11/tests/test_exceptions.cpp
index 706b500f2..ae28abb48 100644
--- a/ext/pybind11/tests/test_exceptions.cpp
+++ b/ext/pybind11/tests/test_exceptions.cpp
@@ -58,34 +58,6 @@ class MyException5_1 : public MyException5 {
     using MyException5::MyException5;
 };
 
-void throws1() {
-    throw MyException("this error should go to a custom type");
-}
-
-void throws2() {
-    throw MyException2("this error should go to a standard Python exception");
-}
-
-void throws3() {
-    throw MyException3("this error cannot be translated");
-}
-
-void throws4() {
-    throw MyException4("this error is rethrown");
-}
-
-void throws5() {
-    throw MyException5("this is a helper-defined translated exception");
-}
-
-void throws5_1() {
-    throw MyException5_1("MyException5 subclass");
-}
-
-void throws_logic_error() {
-    throw std::logic_error("this error should fall through to the standard handler");
-}
-
 struct PythonCallInDestructor {
     PythonCallInDestructor(const py::dict &d) : d(d) {}
     ~PythonCallInDestructor() { d["good"] = true; }
@@ -93,7 +65,11 @@ struct PythonCallInDestructor {
     py::dict d;
 };
 
-test_initializer custom_exceptions([](py::module &m) {
+TEST_SUBMODULE(exceptions, m) {
+    m.def("throw_std_exception", []() {
+        throw std::runtime_error("This exception was intentionally thrown.");
+    });
+
     // make a new custom exception and use it as a translation target
     static py::exception<MyException> ex(m, "MyException");
     py::register_exception_translator([](std::exception_ptr p) {
@@ -133,13 +109,20 @@ test_initializer custom_exceptions([](py::module &m) {
     // A slightly more complicated one that declares MyException5_1 as a subclass of MyException5
     py::register_exception<MyException5_1>(m, "MyException5_1", ex5.ptr());
 
-    m.def("throws1", &throws1);
-    m.def("throws2", &throws2);
-    m.def("throws3", &throws3);
-    m.def("throws4", &throws4);
-    m.def("throws5", &throws5);
-    m.def("throws5_1", &throws5_1);
-    m.def("throws_logic_error", &throws_logic_error);
+    m.def("throws1", []() { throw MyException("this error should go to a custom type"); });
+    m.def("throws2", []() { throw MyException2("this error should go to a standard Python exception"); });
+    m.def("throws3", []() { throw MyException3("this error cannot be translated"); });
+    m.def("throws4", []() { throw MyException4("this error is rethrown"); });
+    m.def("throws5", []() { throw MyException5("this is a helper-defined translated exception"); });
+    m.def("throws5_1", []() { throw MyException5_1("MyException5 subclass"); });
+    m.def("throws_logic_error", []() { throw std::logic_error("this error should fall through to the standard handler"); });
+    m.def("exception_matches", []() {
+        py::dict foo;
+        try { foo["bar"]; }
+        catch (py::error_already_set& ex) {
+            if (!ex.matches(PyExc_KeyError)) throw;
+        }
+    });
 
     m.def("throw_already_set", [](bool err) {
         if (err)
@@ -170,4 +153,16 @@ test_initializer custom_exceptions([](py::module &m) {
         }
         return false;
     });
-});
+
+    // test_nested_throws
+    m.def("try_catch", [m](py::object exc_type, py::function f, py::args args) {
+        try { f(*args); }
+        catch (py::error_already_set &ex) {
+            if (ex.matches(exc_type))
+                py::print(ex.what());
+            else
+                throw;
+        }
+    });
+
+}
diff --git a/ext/pybind11/tests/test_exceptions.py b/ext/pybind11/tests/test_exceptions.py
index 0025e4eb6..8d37c09b8 100644
--- a/ext/pybind11/tests/test_exceptions.py
+++ b/ext/pybind11/tests/test_exceptions.py
@@ -1,74 +1,144 @@
 import pytest
 
+from pybind11_tests import exceptions as m
+import pybind11_cross_module_tests as cm
 
-def test_error_already_set(msg):
-    from pybind11_tests import throw_already_set
 
+def test_std_exception(msg):
     with pytest.raises(RuntimeError) as excinfo:
-        throw_already_set(False)
+        m.throw_std_exception()
+    assert msg(excinfo.value) == "This exception was intentionally thrown."
+
+
+def test_error_already_set(msg):
+    with pytest.raises(RuntimeError) as excinfo:
+        m.throw_already_set(False)
     assert msg(excinfo.value) == "Unknown internal error occurred"
 
     with pytest.raises(ValueError) as excinfo:
-        throw_already_set(True)
+        m.throw_already_set(True)
     assert msg(excinfo.value) == "foo"
 
 
-def test_python_call_in_catch():
-    from pybind11_tests import python_call_in_destructor
+def test_cross_module_exceptions():
+    with pytest.raises(RuntimeError) as excinfo:
+        cm.raise_runtime_error()
+    assert str(excinfo.value) == "My runtime error"
+
+    with pytest.raises(ValueError) as excinfo:
+        cm.raise_value_error()
+    assert str(excinfo.value) == "My value error"
+
+    with pytest.raises(ValueError) as excinfo:
+        cm.throw_pybind_value_error()
+    assert str(excinfo.value) == "pybind11 value error"
+
+    with pytest.raises(TypeError) as excinfo:
+        cm.throw_pybind_type_error()
+    assert str(excinfo.value) == "pybind11 type error"
+
+    with pytest.raises(StopIteration) as excinfo:
+        cm.throw_stop_iteration()
+
 
+def test_python_call_in_catch():
     d = {}
-    assert python_call_in_destructor(d) is True
+    assert m.python_call_in_destructor(d) is True
     assert d["good"] is True
 
 
-def test_custom(msg):
-    from pybind11_tests import (MyException, MyException5, MyException5_1,
-                                throws1, throws2, throws3, throws4, throws5, throws5_1,
-                                throws_logic_error)
+def test_exception_matches():
+    m.exception_matches()
 
-    # Can we catch a MyException?"
-    with pytest.raises(MyException) as excinfo:
-        throws1()
+
+def test_custom(msg):
+    # Can we catch a MyException?
+    with pytest.raises(m.MyException) as excinfo:
+        m.throws1()
     assert msg(excinfo.value) == "this error should go to a custom type"
 
     # Can we translate to standard Python exceptions?
     with pytest.raises(RuntimeError) as excinfo:
-        throws2()
+        m.throws2()
     assert msg(excinfo.value) == "this error should go to a standard Python exception"
 
     # Can we handle unknown exceptions?
     with pytest.raises(RuntimeError) as excinfo:
-        throws3()
+        m.throws3()
     assert msg(excinfo.value) == "Caught an unknown exception!"
 
     # Can we delegate to another handler by rethrowing?
-    with pytest.raises(MyException) as excinfo:
-        throws4()
+    with pytest.raises(m.MyException) as excinfo:
+        m.throws4()
     assert msg(excinfo.value) == "this error is rethrown"
 
-    # "Can we fall-through to the default handler?"
+    # Can we fall-through to the default handler?
     with pytest.raises(RuntimeError) as excinfo:
-        throws_logic_error()
+        m.throws_logic_error()
     assert msg(excinfo.value) == "this error should fall through to the standard handler"
 
     # Can we handle a helper-declared exception?
-    with pytest.raises(MyException5) as excinfo:
-        throws5()
+    with pytest.raises(m.MyException5) as excinfo:
+        m.throws5()
     assert msg(excinfo.value) == "this is a helper-defined translated exception"
 
     # Exception subclassing:
-    with pytest.raises(MyException5) as excinfo:
-        throws5_1()
+    with pytest.raises(m.MyException5) as excinfo:
+        m.throws5_1()
     assert msg(excinfo.value) == "MyException5 subclass"
-    assert isinstance(excinfo.value, MyException5_1)
+    assert isinstance(excinfo.value, m.MyException5_1)
 
-    with pytest.raises(MyException5_1) as excinfo:
-        throws5_1()
+    with pytest.raises(m.MyException5_1) as excinfo:
+        m.throws5_1()
     assert msg(excinfo.value) == "MyException5 subclass"
 
-    with pytest.raises(MyException5) as excinfo:
+    with pytest.raises(m.MyException5) as excinfo:
         try:
-            throws5()
-        except MyException5_1:
+            m.throws5()
+        except m.MyException5_1:
             raise RuntimeError("Exception error: caught child from parent")
     assert msg(excinfo.value) == "this is a helper-defined translated exception"
+
+
+def test_nested_throws(capture):
+    """Tests nested (e.g. C++ -> Python -> C++) exception handling"""
+
+    def throw_myex():
+        raise m.MyException("nested error")
+
+    def throw_myex5():
+        raise m.MyException5("nested error 5")
+
+    # In the comments below, the exception is caught in the first step, thrown in the last step
+
+    # C++ -> Python
+    with capture:
+        m.try_catch(m.MyException5, throw_myex5)
+    assert str(capture).startswith("MyException5: nested error 5")
+
+    # Python -> C++ -> Python
+    with pytest.raises(m.MyException) as excinfo:
+        m.try_catch(m.MyException5, throw_myex)
+    assert str(excinfo.value) == "nested error"
+
+    def pycatch(exctype, f, *args):
+        try:
+            f(*args)
+        except m.MyException as e:
+            print(e)
+
+    # C++ -> Python -> C++ -> Python
+    with capture:
+        m.try_catch(
+            m.MyException5, pycatch, m.MyException, m.try_catch, m.MyException, throw_myex5)
+    assert str(capture).startswith("MyException5: nested error 5")
+
+    # C++ -> Python -> C++
+    with capture:
+        m.try_catch(m.MyException, pycatch, m.MyException5, m.throws4)
+    assert capture == "this error is rethrown"
+
+    # Python -> C++ -> Python -> C++
+    with pytest.raises(m.MyException5) as excinfo:
+        m.try_catch(m.MyException, pycatch, m.MyException, m.throws5)
+    assert str(excinfo.value) == "this is a helper-defined translated exception"
diff --git a/ext/pybind11/tests/test_factory_constructors.cpp b/ext/pybind11/tests/test_factory_constructors.cpp
new file mode 100644
index 000000000..fb33377b2
--- /dev/null
+++ b/ext/pybind11/tests/test_factory_constructors.cpp
@@ -0,0 +1,337 @@
+/*
+    tests/test_factory_constructors.cpp -- tests construction from a factory function
+                                           via py::init_factory()
+
+    Copyright (c) 2017 Jason Rhinelander <jason@imaginary.ca>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include "constructor_stats.h"
+#include <cmath>
+
+// Classes for testing python construction via C++ factory function:
+// Not publically constructible, copyable, or movable:
+class TestFactory1 {
+    friend class TestFactoryHelper;
+    TestFactory1() : value("(empty)") { print_default_created(this); }
+    TestFactory1(int v) : value(std::to_string(v)) { print_created(this, value); }
+    TestFactory1(std::string v) : value(std::move(v)) { print_created(this, value); }
+    TestFactory1(TestFactory1 &&) = delete;
+    TestFactory1(const TestFactory1 &) = delete;
+    TestFactory1 &operator=(TestFactory1 &&) = delete;
+    TestFactory1 &operator=(const TestFactory1 &) = delete;
+public:
+    std::string value;
+    ~TestFactory1() { print_destroyed(this); }
+};
+// Non-public construction, but moveable:
+class TestFactory2 {
+    friend class TestFactoryHelper;
+    TestFactory2() : value("(empty2)") { print_default_created(this); }
+    TestFactory2(int v) : value(std::to_string(v)) { print_created(this, value); }
+    TestFactory2(std::string v) : value(std::move(v)) { print_created(this, value); }
+public:
+    TestFactory2(TestFactory2 &&m) { value = std::move(m.value); print_move_created(this); }
+    TestFactory2 &operator=(TestFactory2 &&m) { value = std::move(m.value); print_move_assigned(this); return *this; }
+    std::string value;
+    ~TestFactory2() { print_destroyed(this); }
+};
+// Mixed direct/factory construction:
+class TestFactory3 {
+protected:
+    friend class TestFactoryHelper;
+    TestFactory3() : value("(empty3)") { print_default_created(this); }
+    TestFactory3(int v) : value(std::to_string(v)) { print_created(this, value); }
+public:
+    TestFactory3(std::string v) : value(std::move(v)) { print_created(this, value); }
+    TestFactory3(TestFactory3 &&m) { value = std::move(m.value); print_move_created(this); }
+    TestFactory3 &operator=(TestFactory3 &&m) { value = std::move(m.value); print_move_assigned(this); return *this; }
+    std::string value;
+    virtual ~TestFactory3() { print_destroyed(this); }
+};
+// Inheritance test
+class TestFactory4 : public TestFactory3 {
+public:
+    TestFactory4() : TestFactory3() { print_default_created(this); }
+    TestFactory4(int v) : TestFactory3(v) { print_created(this, v); }
+    virtual ~TestFactory4() { print_destroyed(this); }
+};
+// Another class for an invalid downcast test
+class TestFactory5 : public TestFactory3 {
+public:
+    TestFactory5(int i) : TestFactory3(i) { print_created(this, i); }
+    virtual ~TestFactory5() { print_destroyed(this); }
+};
+
+class TestFactory6 {
+protected:
+    int value;
+    bool alias = false;
+public:
+    TestFactory6(int i) : value{i} { print_created(this, i); }
+    TestFactory6(TestFactory6 &&f) { print_move_created(this); value = f.value; alias = f.alias; }
+    TestFactory6(const TestFactory6 &f) { print_copy_created(this); value = f.value; alias = f.alias; }
+    virtual ~TestFactory6() { print_destroyed(this); }
+    virtual int get() { return value; }
+    bool has_alias() { return alias; }
+};
+class PyTF6 : public TestFactory6 {
+public:
+    // Special constructor that allows the factory to construct a PyTF6 from a TestFactory6 only
+    // when an alias is needed:
+    PyTF6(TestFactory6 &&base) : TestFactory6(std::move(base)) { alias = true; print_created(this, "move", value); }
+    PyTF6(int i) : TestFactory6(i) { alias = true; print_created(this, i); }
+    PyTF6(PyTF6 &&f) : TestFactory6(std::move(f)) { print_move_created(this); }
+    PyTF6(const PyTF6 &f) : TestFactory6(f) { print_copy_created(this); }
+    PyTF6(std::string s) : TestFactory6((int) s.size()) { alias = true; print_created(this, s); }
+    virtual ~PyTF6() { print_destroyed(this); }
+    int get() override { PYBIND11_OVERLOAD(int, TestFactory6, get, /*no args*/); }
+};
+
+class TestFactory7 {
+protected:
+    int value;
+    bool alias = false;
+public:
+    TestFactory7(int i) : value{i} { print_created(this, i); }
+    TestFactory7(TestFactory7 &&f) { print_move_created(this); value = f.value; alias = f.alias; }
+    TestFactory7(const TestFactory7 &f) { print_copy_created(this); value = f.value; alias = f.alias; }
+    virtual ~TestFactory7() { print_destroyed(this); }
+    virtual int get() { return value; }
+    bool has_alias() { return alias; }
+};
+class PyTF7 : public TestFactory7 {
+public:
+    PyTF7(int i) : TestFactory7(i) { alias = true; print_created(this, i); }
+    PyTF7(PyTF7 &&f) : TestFactory7(std::move(f)) { print_move_created(this); }
+    PyTF7(const PyTF7 &f) : TestFactory7(f) { print_copy_created(this); }
+    virtual ~PyTF7() { print_destroyed(this); }
+    int get() override { PYBIND11_OVERLOAD(int, TestFactory7, get, /*no args*/); }
+};
+
+
+class TestFactoryHelper {
+public:
+    // Non-movable, non-copyable type:
+    // Return via pointer:
+    static TestFactory1 *construct1() { return new TestFactory1(); }
+    // Holder:
+    static std::unique_ptr<TestFactory1> construct1(int a) { return std::unique_ptr<TestFactory1>(new TestFactory1(a)); }
+    // pointer again
+    static TestFactory1 *construct1_string(std::string a) { return new TestFactory1(a); }
+
+    // Moveable type:
+    // pointer:
+    static TestFactory2 *construct2() { return new TestFactory2(); }
+    // holder:
+    static std::unique_ptr<TestFactory2> construct2(int a) { return std::unique_ptr<TestFactory2>(new TestFactory2(a)); }
+    // by value moving:
+    static TestFactory2 construct2(std::string a) { return TestFactory2(a); }
+
+    // shared_ptr holder type:
+    // pointer:
+    static TestFactory3 *construct3() { return new TestFactory3(); }
+    // holder:
+    static std::shared_ptr<TestFactory3> construct3(int a) { return std::shared_ptr<TestFactory3>(new TestFactory3(a)); }
+};
+
+TEST_SUBMODULE(factory_constructors, m) {
+
+    // Define various trivial types to allow simpler overload resolution:
+    py::module m_tag = m.def_submodule("tag");
+#define MAKE_TAG_TYPE(Name) \
+    struct Name##_tag {}; \
+    py::class_<Name##_tag>(m_tag, #Name "_tag").def(py::init<>()); \
+    m_tag.attr(#Name) = py::cast(Name##_tag{})
+    MAKE_TAG_TYPE(pointer);
+    MAKE_TAG_TYPE(unique_ptr);
+    MAKE_TAG_TYPE(move);
+    MAKE_TAG_TYPE(shared_ptr);
+    MAKE_TAG_TYPE(derived);
+    MAKE_TAG_TYPE(TF4);
+    MAKE_TAG_TYPE(TF5);
+    MAKE_TAG_TYPE(null_ptr);
+    MAKE_TAG_TYPE(base);
+    MAKE_TAG_TYPE(invalid_base);
+    MAKE_TAG_TYPE(alias);
+    MAKE_TAG_TYPE(unaliasable);
+    MAKE_TAG_TYPE(mixed);
+
+    // test_init_factory_basic, test_bad_type
+    py::class_<TestFactory1>(m, "TestFactory1")
+        .def(py::init([](unique_ptr_tag, int v) { return TestFactoryHelper::construct1(v); }))
+        .def(py::init(&TestFactoryHelper::construct1_string)) // raw function pointer
+        .def(py::init([](pointer_tag) { return TestFactoryHelper::construct1(); }))
+        .def(py::init([](py::handle, int v, py::handle) { return TestFactoryHelper::construct1(v); }))
+        .def_readwrite("value", &TestFactory1::value)
+        ;
+    py::class_<TestFactory2>(m, "TestFactory2")
+        .def(py::init([](pointer_tag, int v) { return TestFactoryHelper::construct2(v); }))
+        .def(py::init([](unique_ptr_tag, std::string v) { return TestFactoryHelper::construct2(v); }))
+        .def(py::init([](move_tag) { return TestFactoryHelper::construct2(); }))
+        .def_readwrite("value", &TestFactory2::value)
+        ;
+
+    // Stateful & reused:
+    int c = 1;
+    auto c4a = [c](pointer_tag, TF4_tag, int a) { (void) c; return new TestFactory4(a);};
+
+    // test_init_factory_basic, test_init_factory_casting
+    py::class_<TestFactory3, std::shared_ptr<TestFactory3>>(m, "TestFactory3")
+        .def(py::init([](pointer_tag, int v) { return TestFactoryHelper::construct3(v); }))
+        .def(py::init([](shared_ptr_tag) { return TestFactoryHelper::construct3(); }))
+        .def("__init__", [](TestFactory3 &self, std::string v) { new (&self) TestFactory3(v); }) // placement-new ctor
+
+        // factories returning a derived type:
+        .def(py::init(c4a)) // derived ptr
+        .def(py::init([](pointer_tag, TF5_tag, int a) { return new TestFactory5(a); }))
+        // derived shared ptr:
+        .def(py::init([](shared_ptr_tag, TF4_tag, int a) { return std::make_shared<TestFactory4>(a); }))
+        .def(py::init([](shared_ptr_tag, TF5_tag, int a) { return std::make_shared<TestFactory5>(a); }))
+
+        // Returns nullptr:
+        .def(py::init([](null_ptr_tag) { return (TestFactory3 *) nullptr; }))
+
+        .def_readwrite("value", &TestFactory3::value)
+        ;
+
+    // test_init_factory_casting
+    py::class_<TestFactory4, TestFactory3, std::shared_ptr<TestFactory4>>(m, "TestFactory4")
+        .def(py::init(c4a)) // pointer
+        ;
+
+    // Doesn't need to be registered, but registering makes getting ConstructorStats easier:
+    py::class_<TestFactory5, TestFactory3, std::shared_ptr<TestFactory5>>(m, "TestFactory5");
+
+    // test_init_factory_alias
+    // Alias testing
+    py::class_<TestFactory6, PyTF6>(m, "TestFactory6")
+        .def(py::init([](base_tag, int i) { return TestFactory6(i); }))
+        .def(py::init([](alias_tag, int i) { return PyTF6(i); }))
+        .def(py::init([](alias_tag, std::string s) { return PyTF6(s); }))
+        .def(py::init([](alias_tag, pointer_tag, int i) { return new PyTF6(i); }))
+        .def(py::init([](base_tag, pointer_tag, int i) { return new TestFactory6(i); }))
+        .def(py::init([](base_tag, alias_tag, pointer_tag, int i) { return (TestFactory6 *) new PyTF6(i); }))
+
+        .def("get", &TestFactory6::get)
+        .def("has_alias", &TestFactory6::has_alias)
+
+        .def_static("get_cstats", &ConstructorStats::get<TestFactory6>, py::return_value_policy::reference)
+        .def_static("get_alias_cstats", &ConstructorStats::get<PyTF6>, py::return_value_policy::reference)
+        ;
+
+    // test_init_factory_dual
+    // Separate alias constructor testing
+    py::class_<TestFactory7, PyTF7, std::shared_ptr<TestFactory7>>(m, "TestFactory7")
+        .def(py::init(
+            [](int i) { return TestFactory7(i); },
+            [](int i) { return PyTF7(i); }))
+        .def(py::init(
+            [](pointer_tag, int i) { return new TestFactory7(i); },
+            [](pointer_tag, int i) { return new PyTF7(i); }))
+        .def(py::init(
+            [](mixed_tag, int i) { return new TestFactory7(i); },
+            [](mixed_tag, int i) { return PyTF7(i); }))
+        .def(py::init(
+            [](mixed_tag, std::string s) { return TestFactory7((int) s.size()); },
+            [](mixed_tag, std::string s) { return new PyTF7((int) s.size()); }))
+        .def(py::init(
+            [](base_tag, pointer_tag, int i) { return new TestFactory7(i); },
+            [](base_tag, pointer_tag, int i) { return (TestFactory7 *) new PyTF7(i); }))
+        .def(py::init(
+            [](alias_tag, pointer_tag, int i) { return new PyTF7(i); },
+            [](alias_tag, pointer_tag, int i) { return new PyTF7(10*i); }))
+        .def(py::init(
+            [](shared_ptr_tag, base_tag, int i) { return std::make_shared<TestFactory7>(i); },
+            [](shared_ptr_tag, base_tag, int i) { auto *p = new PyTF7(i); return std::shared_ptr<TestFactory7>(p); }))
+        .def(py::init(
+            [](shared_ptr_tag, invalid_base_tag, int i) { return std::make_shared<TestFactory7>(i); },
+            [](shared_ptr_tag, invalid_base_tag, int i) { return std::make_shared<TestFactory7>(i); })) // <-- invalid alias factory
+
+        .def("get", &TestFactory7::get)
+        .def("has_alias", &TestFactory7::has_alias)
+
+        .def_static("get_cstats", &ConstructorStats::get<TestFactory7>, py::return_value_policy::reference)
+        .def_static("get_alias_cstats", &ConstructorStats::get<PyTF7>, py::return_value_policy::reference)
+        ;
+
+    // test_placement_new_alternative
+    // Class with a custom new operator but *without* a placement new operator (issue #948)
+    class NoPlacementNew {
+    public:
+        NoPlacementNew(int i) : i(i) { }
+        static void *operator new(std::size_t s) {
+            auto *p = ::operator new(s);
+            py::print("operator new called, returning", reinterpret_cast<uintptr_t>(p));
+            return p;
+        }
+        static void operator delete(void *p) {
+            py::print("operator delete called on", reinterpret_cast<uintptr_t>(p));
+            ::operator delete(p);
+        }
+        int i;
+    };
+    // As of 2.2, `py::init<args>` no longer requires placement new
+    py::class_<NoPlacementNew>(m, "NoPlacementNew")
+        .def(py::init<int>())
+        .def(py::init([]() { return new NoPlacementNew(100); }))
+        .def_readwrite("i", &NoPlacementNew::i)
+        ;
+
+
+    // test_reallocations
+    // Class that has verbose operator_new/operator_delete calls
+    struct NoisyAlloc {
+        NoisyAlloc(int i) { py::print(py::str("NoisyAlloc(int {})").format(i)); }
+        NoisyAlloc(double d) { py::print(py::str("NoisyAlloc(double {})").format(d)); }
+        ~NoisyAlloc() { py::print("~NoisyAlloc()"); }
+
+        static void *operator new(size_t s) { py::print("noisy new"); return ::operator new(s); }
+        static void *operator new(size_t, void *p) { py::print("noisy placement new"); return p; }
+        static void operator delete(void *p, size_t) { py::print("noisy delete"); ::operator delete(p); }
+        static void operator delete(void *, void *) { py::print("noisy placement delete"); }
+#if defined(_MSC_VER) && _MSC_VER < 1910
+        // MSVC 2015 bug: the above "noisy delete" isn't invoked (fixed in MSVC 2017)
+        static void operator delete(void *p) { py::print("noisy delete"); ::operator delete(p); }
+#endif
+    };
+    py::class_<NoisyAlloc>(m, "NoisyAlloc")
+        // Since these overloads have the same number of arguments, the dispatcher will try each of
+        // them until the arguments convert.  Thus we can get a pre-allocation here when passing a
+        // single non-integer:
+        .def("__init__", [](NoisyAlloc *a, int i) { new (a) NoisyAlloc(i); }) // Regular constructor, runs first, requires preallocation
+        .def(py::init([](double d) { return new NoisyAlloc(d); }))
+
+        // The two-argument version: first the factory pointer overload.
+        .def(py::init([](int i, int) { return new NoisyAlloc(i); }))
+        // Return-by-value:
+        .def(py::init([](double d, int) { return NoisyAlloc(d); }))
+        // Old-style placement new init; requires preallocation
+        .def("__init__", [](NoisyAlloc &a, double d, double) { new (&a) NoisyAlloc(d); })
+        // Requires deallocation of previous overload preallocated value:
+        .def(py::init([](int i, double) { return new NoisyAlloc(i); }))
+        // Regular again: requires yet another preallocation
+        .def("__init__", [](NoisyAlloc &a, int i, std::string) { new (&a) NoisyAlloc(i); })
+        ;
+
+
+
+
+    // static_assert testing (the following def's should all fail with appropriate compilation errors):
+#if 0
+    struct BadF1Base {};
+    struct BadF1 : BadF1Base {};
+    struct PyBadF1 : BadF1 {};
+    py::class_<BadF1, PyBadF1, std::shared_ptr<BadF1>> bf1(m, "BadF1");
+    // wrapped factory function must return a compatible pointer, holder, or value
+    bf1.def(py::init([]() { return 3; }));
+    // incompatible factory function pointer return type
+    bf1.def(py::init([]() { static int three = 3; return &three; }));
+    // incompatible factory function std::shared_ptr<T> return type: cannot convert shared_ptr<T> to holder
+    // (non-polymorphic base)
+    bf1.def(py::init([]() { return std::shared_ptr<BadF1Base>(new BadF1()); }));
+#endif
+}
diff --git a/ext/pybind11/tests/test_factory_constructors.py b/ext/pybind11/tests/test_factory_constructors.py
new file mode 100644
index 000000000..78a3910ad
--- /dev/null
+++ b/ext/pybind11/tests/test_factory_constructors.py
@@ -0,0 +1,459 @@
+import pytest
+import re
+
+from pybind11_tests import factory_constructors as m
+from pybind11_tests.factory_constructors import tag
+from pybind11_tests import ConstructorStats
+
+
+def test_init_factory_basic():
+    """Tests py::init_factory() wrapper around various ways of returning the object"""
+
+    cstats = [ConstructorStats.get(c) for c in [m.TestFactory1, m.TestFactory2, m.TestFactory3]]
+    cstats[0].alive()  # force gc
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    x1 = m.TestFactory1(tag.unique_ptr, 3)
+    assert x1.value == "3"
+    y1 = m.TestFactory1(tag.pointer)
+    assert y1.value == "(empty)"
+    z1 = m.TestFactory1("hi!")
+    assert z1.value == "hi!"
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 3
+
+    x2 = m.TestFactory2(tag.move)
+    assert x2.value == "(empty2)"
+    y2 = m.TestFactory2(tag.pointer, 7)
+    assert y2.value == "7"
+    z2 = m.TestFactory2(tag.unique_ptr, "hi again")
+    assert z2.value == "hi again"
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 6
+
+    x3 = m.TestFactory3(tag.shared_ptr)
+    assert x3.value == "(empty3)"
+    y3 = m.TestFactory3(tag.pointer, 42)
+    assert y3.value == "42"
+    z3 = m.TestFactory3("bye")
+    assert z3.value == "bye"
+
+    with pytest.raises(TypeError) as excinfo:
+        m.TestFactory3(tag.null_ptr)
+    assert str(excinfo.value) == "pybind11::init(): factory function returned nullptr"
+
+    assert [i.alive() for i in cstats] == [3, 3, 3]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 9
+
+    del x1, y2, y3, z3
+    assert [i.alive() for i in cstats] == [2, 2, 1]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 5
+    del x2, x3, y1, z1, z2
+    assert [i.alive() for i in cstats] == [0, 0, 0]
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    assert [i.values() for i in cstats] == [
+        ["3", "hi!"],
+        ["7", "hi again"],
+        ["42", "bye"]
+    ]
+    assert [i.default_constructions for i in cstats] == [1, 1, 1]
+
+
+def test_init_factory_signature(msg):
+    with pytest.raises(TypeError) as excinfo:
+        m.TestFactory1("invalid", "constructor", "arguments")
+    assert msg(excinfo.value) == """
+        __init__(): incompatible constructor arguments. The following argument types are supported:
+            1. m.factory_constructors.TestFactory1(arg0: m.factory_constructors.tag.unique_ptr_tag, arg1: int)
+            2. m.factory_constructors.TestFactory1(arg0: str)
+            3. m.factory_constructors.TestFactory1(arg0: m.factory_constructors.tag.pointer_tag)
+            4. m.factory_constructors.TestFactory1(arg0: handle, arg1: int, arg2: handle)
+
+        Invoked with: 'invalid', 'constructor', 'arguments'
+    """  # noqa: E501 line too long
+
+    assert msg(m.TestFactory1.__init__.__doc__) == """
+        __init__(*args, **kwargs)
+        Overloaded function.
+
+        1. __init__(self: m.factory_constructors.TestFactory1, arg0: m.factory_constructors.tag.unique_ptr_tag, arg1: int) -> None
+
+        2. __init__(self: m.factory_constructors.TestFactory1, arg0: str) -> None
+
+        3. __init__(self: m.factory_constructors.TestFactory1, arg0: m.factory_constructors.tag.pointer_tag) -> None
+
+        4. __init__(self: m.factory_constructors.TestFactory1, arg0: handle, arg1: int, arg2: handle) -> None
+    """  # noqa: E501 line too long
+
+
+def test_init_factory_casting():
+    """Tests py::init_factory() wrapper with various upcasting and downcasting returns"""
+
+    cstats = [ConstructorStats.get(c) for c in [m.TestFactory3, m.TestFactory4, m.TestFactory5]]
+    cstats[0].alive()  # force gc
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    # Construction from derived references:
+    a = m.TestFactory3(tag.pointer, tag.TF4, 4)
+    assert a.value == "4"
+    b = m.TestFactory3(tag.shared_ptr, tag.TF4, 5)
+    assert b.value == "5"
+    c = m.TestFactory3(tag.pointer, tag.TF5, 6)
+    assert c.value == "6"
+    d = m.TestFactory3(tag.shared_ptr, tag.TF5, 7)
+    assert d.value == "7"
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 4
+
+    # Shared a lambda with TF3:
+    e = m.TestFactory4(tag.pointer, tag.TF4, 8)
+    assert e.value == "8"
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 5
+    assert [i.alive() for i in cstats] == [5, 3, 2]
+
+    del a
+    assert [i.alive() for i in cstats] == [4, 2, 2]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 4
+
+    del b, c, e
+    assert [i.alive() for i in cstats] == [1, 0, 1]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 1
+
+    del d
+    assert [i.alive() for i in cstats] == [0, 0, 0]
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    assert [i.values() for i in cstats] == [
+        ["4", "5", "6", "7", "8"],
+        ["4", "5", "8"],
+        ["6", "7"]
+    ]
+
+
+def test_init_factory_alias():
+    """Tests py::init_factory() wrapper with value conversions and alias types"""
+
+    cstats = [m.TestFactory6.get_cstats(), m.TestFactory6.get_alias_cstats()]
+    cstats[0].alive()  # force gc
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    a = m.TestFactory6(tag.base, 1)
+    assert a.get() == 1
+    assert not a.has_alias()
+    b = m.TestFactory6(tag.alias, "hi there")
+    assert b.get() == 8
+    assert b.has_alias()
+    c = m.TestFactory6(tag.alias, 3)
+    assert c.get() == 3
+    assert c.has_alias()
+    d = m.TestFactory6(tag.alias, tag.pointer, 4)
+    assert d.get() == 4
+    assert d.has_alias()
+    e = m.TestFactory6(tag.base, tag.pointer, 5)
+    assert e.get() == 5
+    assert not e.has_alias()
+    f = m.TestFactory6(tag.base, tag.alias, tag.pointer, 6)
+    assert f.get() == 6
+    assert f.has_alias()
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 6
+    assert [i.alive() for i in cstats] == [6, 4]
+
+    del a, b, e
+    assert [i.alive() for i in cstats] == [3, 3]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 3
+    del f, c, d
+    assert [i.alive() for i in cstats] == [0, 0]
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    class MyTest(m.TestFactory6):
+        def __init__(self, *args):
+            m.TestFactory6.__init__(self, *args)
+
+        def get(self):
+            return -5 + m.TestFactory6.get(self)
+
+    # Return Class by value, moved into new alias:
+    z = MyTest(tag.base, 123)
+    assert z.get() == 118
+    assert z.has_alias()
+
+    # Return alias by value, moved into new alias:
+    y = MyTest(tag.alias, "why hello!")
+    assert y.get() == 5
+    assert y.has_alias()
+
+    # Return Class by pointer, moved into new alias then original destroyed:
+    x = MyTest(tag.base, tag.pointer, 47)
+    assert x.get() == 42
+    assert x.has_alias()
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 3
+    assert [i.alive() for i in cstats] == [3, 3]
+    del x, y, z
+    assert [i.alive() for i in cstats] == [0, 0]
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    assert [i.values() for i in cstats] == [
+        ["1", "8", "3", "4", "5", "6", "123", "10", "47"],
+        ["hi there", "3", "4", "6", "move", "123", "why hello!", "move", "47"]
+    ]
+
+
+def test_init_factory_dual():
+    """Tests init factory functions with dual main/alias factory functions"""
+    from pybind11_tests.factory_constructors import TestFactory7
+
+    cstats = [TestFactory7.get_cstats(), TestFactory7.get_alias_cstats()]
+    cstats[0].alive()  # force gc
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    class PythFactory7(TestFactory7):
+        def get(self):
+            return 100 + TestFactory7.get(self)
+
+    a1 = TestFactory7(1)
+    a2 = PythFactory7(2)
+    assert a1.get() == 1
+    assert a2.get() == 102
+    assert not a1.has_alias()
+    assert a2.has_alias()
+
+    b1 = TestFactory7(tag.pointer, 3)
+    b2 = PythFactory7(tag.pointer, 4)
+    assert b1.get() == 3
+    assert b2.get() == 104
+    assert not b1.has_alias()
+    assert b2.has_alias()
+
+    c1 = TestFactory7(tag.mixed, 5)
+    c2 = PythFactory7(tag.mixed, 6)
+    assert c1.get() == 5
+    assert c2.get() == 106
+    assert not c1.has_alias()
+    assert c2.has_alias()
+
+    d1 = TestFactory7(tag.base, tag.pointer, 7)
+    d2 = PythFactory7(tag.base, tag.pointer, 8)
+    assert d1.get() == 7
+    assert d2.get() == 108
+    assert not d1.has_alias()
+    assert d2.has_alias()
+
+    # Both return an alias; the second multiplies the value by 10:
+    e1 = TestFactory7(tag.alias, tag.pointer, 9)
+    e2 = PythFactory7(tag.alias, tag.pointer, 10)
+    assert e1.get() == 9
+    assert e2.get() == 200
+    assert e1.has_alias()
+    assert e2.has_alias()
+
+    f1 = TestFactory7(tag.shared_ptr, tag.base, 11)
+    f2 = PythFactory7(tag.shared_ptr, tag.base, 12)
+    assert f1.get() == 11
+    assert f2.get() == 112
+    assert not f1.has_alias()
+    assert f2.has_alias()
+
+    g1 = TestFactory7(tag.shared_ptr, tag.invalid_base, 13)
+    assert g1.get() == 13
+    assert not g1.has_alias()
+    with pytest.raises(TypeError) as excinfo:
+        PythFactory7(tag.shared_ptr, tag.invalid_base, 14)
+    assert (str(excinfo.value) ==
+            "pybind11::init(): construction failed: returned holder-wrapped instance is not an "
+            "alias instance")
+
+    assert [i.alive() for i in cstats] == [13, 7]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 13
+
+    del a1, a2, b1, d1, e1, e2
+    assert [i.alive() for i in cstats] == [7, 4]
+    assert ConstructorStats.detail_reg_inst() == n_inst + 7
+    del b2, c1, c2, d2, f1, f2, g1
+    assert [i.alive() for i in cstats] == [0, 0]
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    assert [i.values() for i in cstats] == [
+        ["1", "2", "3", "4", "5", "6", "7", "8", "9", "100", "11", "12", "13", "14"],
+        ["2", "4", "6", "8", "9", "100", "12"]
+    ]
+
+
+def test_no_placement_new(capture):
+    """Prior to 2.2, `py::init<...>` relied on the type supporting placement
+    new; this tests a class without placement new support."""
+    with capture:
+        a = m.NoPlacementNew(123)
+
+    found = re.search(r'^operator new called, returning (\d+)\n$', str(capture))
+    assert found
+    assert a.i == 123
+    with capture:
+        del a
+        pytest.gc_collect()
+    assert capture == "operator delete called on " + found.group(1)
+
+    with capture:
+        b = m.NoPlacementNew()
+
+    found = re.search(r'^operator new called, returning (\d+)\n$', str(capture))
+    assert found
+    assert b.i == 100
+    with capture:
+        del b
+        pytest.gc_collect()
+    assert capture == "operator delete called on " + found.group(1)
+
+
+def test_multiple_inheritance():
+    class MITest(m.TestFactory1, m.TestFactory2):
+        def __init__(self):
+            m.TestFactory1.__init__(self, tag.unique_ptr, 33)
+            m.TestFactory2.__init__(self, tag.move)
+
+    a = MITest()
+    assert m.TestFactory1.value.fget(a) == "33"
+    assert m.TestFactory2.value.fget(a) == "(empty2)"
+
+
+def create_and_destroy(*args):
+    a = m.NoisyAlloc(*args)
+    print("---")
+    del a
+    pytest.gc_collect()
+
+
+def strip_comments(s):
+    return re.sub(r'\s+#.*', '', s)
+
+
+def test_reallocations(capture, msg):
+    """When the constructor is overloaded, previous overloads can require a preallocated value.
+    This test makes sure that such preallocated values only happen when they might be necessary,
+    and that they are deallocated properly"""
+
+    pytest.gc_collect()
+
+    with capture:
+        create_and_destroy(1)
+    assert msg(capture) == """
+        noisy new
+        noisy placement new
+        NoisyAlloc(int 1)
+        ---
+        ~NoisyAlloc()
+        noisy delete
+    """
+    with capture:
+        create_and_destroy(1.5)
+    assert msg(capture) == strip_comments("""
+        noisy new               # allocation required to attempt first overload
+        noisy delete            # have to dealloc before considering factory init overload
+        noisy new               # pointer factory calling "new", part 1: allocation
+        NoisyAlloc(double 1.5)  # ... part two, invoking constructor
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+    with capture:
+        create_and_destroy(2, 3)
+    assert msg(capture) == strip_comments("""
+        noisy new          # pointer factory calling "new", allocation
+        NoisyAlloc(int 2)  # constructor
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+    with capture:
+        create_and_destroy(2.5, 3)
+    assert msg(capture) == strip_comments("""
+        NoisyAlloc(double 2.5)  # construction (local func variable: operator_new not called)
+        noisy new               # return-by-value "new" part 1: allocation
+        ~NoisyAlloc()           # moved-away local func variable destruction
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+    with capture:
+        create_and_destroy(3.5, 4.5)
+    assert msg(capture) == strip_comments("""
+        noisy new               # preallocation needed before invoking placement-new overload
+        noisy placement new     # Placement new
+        NoisyAlloc(double 3.5)  # construction
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+    with capture:
+        create_and_destroy(4, 0.5)
+    assert msg(capture) == strip_comments("""
+        noisy new          # preallocation needed before invoking placement-new overload
+        noisy delete       # deallocation of preallocated storage
+        noisy new          # Factory pointer allocation
+        NoisyAlloc(int 4)  # factory pointer construction
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+    with capture:
+        create_and_destroy(5, "hi")
+    assert msg(capture) == strip_comments("""
+        noisy new            # preallocation needed before invoking first placement new
+        noisy delete         # delete before considering new-style constructor
+        noisy new            # preallocation for second placement new
+        noisy placement new  # Placement new in the second placement new overload
+        NoisyAlloc(int 5)    # construction
+        ---
+        ~NoisyAlloc()  # Destructor
+        noisy delete   # operator delete
+    """)
+
+
+@pytest.unsupported_on_py2
+def test_invalid_self():
+    """Tests invocation of the pybind-registered base class with an invalid `self` argument.  You
+    can only actually do this on Python 3: Python 2 raises an exception itself if you try."""
+    class NotPybindDerived(object):
+        pass
+
+    # Attempts to initialize with an invalid type passed as `self`:
+    class BrokenTF1(m.TestFactory1):
+        def __init__(self, bad):
+            if bad == 1:
+                a = m.TestFactory2(tag.pointer, 1)
+                m.TestFactory1.__init__(a, tag.pointer)
+            elif bad == 2:
+                a = NotPybindDerived()
+                m.TestFactory1.__init__(a, tag.pointer)
+
+    # Same as above, but for a class with an alias:
+    class BrokenTF6(m.TestFactory6):
+        def __init__(self, bad):
+            if bad == 1:
+                a = m.TestFactory2(tag.pointer, 1)
+                m.TestFactory6.__init__(a, tag.base, 1)
+            elif bad == 2:
+                a = m.TestFactory2(tag.pointer, 1)
+                m.TestFactory6.__init__(a, tag.alias, 1)
+            elif bad == 3:
+                m.TestFactory6.__init__(NotPybindDerived.__new__(NotPybindDerived), tag.base, 1)
+            elif bad == 4:
+                m.TestFactory6.__init__(NotPybindDerived.__new__(NotPybindDerived), tag.alias, 1)
+
+    for arg in (1, 2):
+        with pytest.raises(TypeError) as excinfo:
+            BrokenTF1(arg)
+        assert str(excinfo.value) == "__init__(self, ...) called with invalid `self` argument"
+
+    for arg in (1, 2, 3, 4):
+        with pytest.raises(TypeError) as excinfo:
+            BrokenTF6(arg)
+        assert str(excinfo.value) == "__init__(self, ...) called with invalid `self` argument"
diff --git a/ext/pybind11/tests/test_inheritance.cpp b/ext/pybind11/tests/test_inheritance.cpp
deleted file mode 100644
index c19f58dc2..000000000
--- a/ext/pybind11/tests/test_inheritance.cpp
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
-    tests/test_inheritance.cpp -- inheritance, automatic upcasting for polymorphic types
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-class Pet {
-public:
-    Pet(const std::string &name, const std::string &species)
-        : m_name(name), m_species(species) {}
-    std::string name() const { return m_name; }
-    std::string species() const { return m_species; }
-private:
-    std::string m_name;
-    std::string m_species;
-};
-
-class Dog : public Pet {
-public:
-    Dog(const std::string &name) : Pet(name, "dog") {}
-    std::string bark() const { return "Woof!"; }
-};
-
-class Rabbit : public Pet {
-public:
-    Rabbit(const std::string &name) : Pet(name, "parrot") {}
-};
-
-class Hamster : public Pet {
-public:
-    Hamster(const std::string &name) : Pet(name, "rodent") {}
-};
-
-class Chimera : public Pet {
-    Chimera() : Pet("Kimmy", "chimera") {}
-};
-
-std::string pet_name_species(const Pet &pet) {
-    return pet.name() + " is a " + pet.species();
-}
-
-std::string dog_bark(const Dog &dog) {
-    return dog.bark();
-}
-
-
-struct BaseClass { virtual ~BaseClass() {} };
-struct DerivedClass1 : BaseClass { };
-struct DerivedClass2 : BaseClass { };
-
-struct MismatchBase1 { };
-struct MismatchDerived1 : MismatchBase1 { };
-
-struct MismatchBase2 { };
-struct MismatchDerived2 : MismatchBase2 { };
-
-test_initializer inheritance([](py::module &m) {
-    py::class_<Pet> pet_class(m, "Pet");
-    pet_class
-        .def(py::init<std::string, std::string>())
-        .def("name", &Pet::name)
-        .def("species", &Pet::species);
-
-    /* One way of declaring a subclass relationship: reference parent's class_ object */
-    py::class_<Dog>(m, "Dog", pet_class)
-        .def(py::init<std::string>());
-
-    /* Another way of declaring a subclass relationship: reference parent's C++ type */
-    py::class_<Rabbit, Pet>(m, "Rabbit")
-        .def(py::init<std::string>());
-
-    /* And another: list parent in class template arguments */
-    py::class_<Hamster, Pet>(m, "Hamster")
-        .def(py::init<std::string>());
-
-    py::class_<Chimera, Pet>(m, "Chimera");
-
-    m.def("pet_name_species", pet_name_species);
-    m.def("dog_bark", dog_bark);
-
-    py::class_<BaseClass>(m, "BaseClass").def(py::init<>());
-    py::class_<DerivedClass1>(m, "DerivedClass1").def(py::init<>());
-    py::class_<DerivedClass2>(m, "DerivedClass2").def(py::init<>());
-
-    m.def("return_class_1", []() -> BaseClass* { return new DerivedClass1(); });
-    m.def("return_class_2", []() -> BaseClass* { return new DerivedClass2(); });
-    m.def("return_class_n", [](int n) -> BaseClass* {
-        if (n == 1) return new DerivedClass1();
-        if (n == 2) return new DerivedClass2();
-        return new BaseClass();
-    });
-    m.def("return_none", []() -> BaseClass* { return nullptr; });
-
-    m.def("test_isinstance", [](py::list l) {
-        struct Unregistered { }; // checks missing type_info code path
-
-        return py::make_tuple(
-            py::isinstance<py::tuple>(l[0]),
-            py::isinstance<py::dict>(l[1]),
-            py::isinstance<Pet>(l[2]),
-            py::isinstance<Pet>(l[3]),
-            py::isinstance<Dog>(l[4]),
-            py::isinstance<Rabbit>(l[5]),
-            py::isinstance<Unregistered>(l[6])
-        );
-    });
-
-    m.def("test_mismatched_holder_type_1", []() {
-        auto m = py::module::import("__main__");
-        py::class_<MismatchBase1, std::shared_ptr<MismatchBase1>>(m, "MismatchBase1");
-        py::class_<MismatchDerived1, MismatchBase1>(m, "MismatchDerived1");
-    });
-    m.def("test_mismatched_holder_type_2", []() {
-        auto m = py::module::import("__main__");
-        py::class_<MismatchBase2>(m, "MismatchBase2");
-        py::class_<MismatchDerived2, std::shared_ptr<MismatchDerived2>, MismatchBase2>(m, "MismatchDerived2");
-    });
-});
diff --git a/ext/pybind11/tests/test_inheritance.py b/ext/pybind11/tests/test_inheritance.py
deleted file mode 100644
index d1f537d1d..000000000
--- a/ext/pybind11/tests/test_inheritance.py
+++ /dev/null
@@ -1,78 +0,0 @@
-import pytest
-
-
-def test_inheritance(msg):
-    from pybind11_tests import Pet, Dog, Rabbit, Hamster, Chimera, dog_bark, pet_name_species
-
-    roger = Rabbit('Rabbit')
-    assert roger.name() + " is a " + roger.species() == "Rabbit is a parrot"
-    assert pet_name_species(roger) == "Rabbit is a parrot"
-
-    polly = Pet('Polly', 'parrot')
-    assert polly.name() + " is a " + polly.species() == "Polly is a parrot"
-    assert pet_name_species(polly) == "Polly is a parrot"
-
-    molly = Dog('Molly')
-    assert molly.name() + " is a " + molly.species() == "Molly is a dog"
-    assert pet_name_species(molly) == "Molly is a dog"
-
-    fred = Hamster('Fred')
-    assert fred.name() + " is a " + fred.species() == "Fred is a rodent"
-
-    assert dog_bark(molly) == "Woof!"
-
-    with pytest.raises(TypeError) as excinfo:
-        dog_bark(polly)
-    assert msg(excinfo.value) == """
-        dog_bark(): incompatible function arguments. The following argument types are supported:
-            1. (arg0: m.Dog) -> str
-
-        Invoked with: <m.Pet object at 0>
-    """
-
-    with pytest.raises(TypeError) as excinfo:
-        Chimera("lion", "goat")
-    assert "No constructor defined!" in str(excinfo.value)
-
-
-def test_automatic_upcasting():
-    from pybind11_tests import return_class_1, return_class_2, return_class_n, return_none
-
-    assert type(return_class_1()).__name__ == "DerivedClass1"
-    assert type(return_class_2()).__name__ == "DerivedClass2"
-    assert type(return_none()).__name__ == "NoneType"
-    # Repeat these a few times in a random order to ensure no invalid caching
-    # is applied
-    assert type(return_class_n(1)).__name__ == "DerivedClass1"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(0)).__name__ == "BaseClass"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(0)).__name__ == "BaseClass"
-    assert type(return_class_n(1)).__name__ == "DerivedClass1"
-
-
-def test_isinstance():
-    from pybind11_tests import test_isinstance, Pet, Dog
-
-    objects = [tuple(), dict(), Pet("Polly", "parrot")] + [Dog("Molly")] * 4
-    expected = (True, True, True, True, True, False, False)
-    assert test_isinstance(objects) == expected
-
-
-def test_holder():
-    from pybind11_tests import test_mismatched_holder_type_1, test_mismatched_holder_type_2
-
-    with pytest.raises(RuntimeError) as excinfo:
-        test_mismatched_holder_type_1()
-
-    assert str(excinfo.value) == ("generic_type: type \"MismatchDerived1\" does not have "
-                                  "a non-default holder type while its base "
-                                  "\"MismatchBase1\" does")
-
-    with pytest.raises(RuntimeError) as excinfo:
-        test_mismatched_holder_type_2()
-
-    assert str(excinfo.value) == ("generic_type: type \"MismatchDerived2\" has a "
-                                  "non-default holder type while its base "
-                                  "\"MismatchBase2\" does not")
diff --git a/ext/pybind11/tests/test_iostream.cpp b/ext/pybind11/tests/test_iostream.cpp
new file mode 100644
index 000000000..e67f88af5
--- /dev/null
+++ b/ext/pybind11/tests/test_iostream.cpp
@@ -0,0 +1,73 @@
+/*
+    tests/test_iostream.cpp -- Usage of scoped_output_redirect
+
+    Copyright (c) 2017 Henry F. Schreiner
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+
+#include <pybind11/iostream.h>
+#include "pybind11_tests.h"
+#include <iostream>
+
+
+void noisy_function(std::string msg, bool flush) {
+
+    std::cout << msg;
+    if (flush)
+        std::cout << std::flush;
+}
+
+void noisy_funct_dual(std::string msg, std::string emsg) {
+    std::cout << msg;
+    std::cerr << emsg;
+}
+
+TEST_SUBMODULE(iostream, m) {
+
+    add_ostream_redirect(m);
+
+    // test_evals
+
+    m.def("captured_output_default", [](std::string msg) {
+        py::scoped_ostream_redirect redir;
+        std::cout << msg << std::flush;
+    });
+
+    m.def("captured_output", [](std::string msg) {
+        py::scoped_ostream_redirect redir(std::cout, py::module::import("sys").attr("stdout"));
+        std::cout << msg << std::flush;
+    });
+
+    m.def("guard_output", &noisy_function,
+            py::call_guard<py::scoped_ostream_redirect>(),
+            py::arg("msg"), py::arg("flush")=true);
+
+    m.def("captured_err", [](std::string msg) {
+        py::scoped_ostream_redirect redir(std::cerr, py::module::import("sys").attr("stderr"));
+        std::cerr << msg << std::flush;
+    });
+
+    m.def("noisy_function", &noisy_function, py::arg("msg"), py::arg("flush") = true);
+
+    m.def("dual_guard", &noisy_funct_dual,
+            py::call_guard<py::scoped_ostream_redirect, py::scoped_estream_redirect>(),
+            py::arg("msg"), py::arg("emsg"));
+
+    m.def("raw_output", [](std::string msg) {
+        std::cout << msg << std::flush;
+    });
+
+    m.def("raw_err", [](std::string msg) {
+        std::cerr << msg << std::flush;
+    });
+
+    m.def("captured_dual", [](std::string msg, std::string emsg) {
+        py::scoped_ostream_redirect redirout(std::cout, py::module::import("sys").attr("stdout"));
+        py::scoped_ostream_redirect redirerr(std::cerr, py::module::import("sys").attr("stderr"));
+        std::cout << msg << std::flush;
+        std::cerr << emsg << std::flush;
+    });
+}
diff --git a/ext/pybind11/tests/test_iostream.py b/ext/pybind11/tests/test_iostream.py
new file mode 100644
index 000000000..3364849a4
--- /dev/null
+++ b/ext/pybind11/tests/test_iostream.py
@@ -0,0 +1,203 @@
+from pybind11_tests import iostream as m
+import sys
+
+from contextlib import contextmanager
+
+try:
+    # Python 3
+    from io import StringIO
+except ImportError:
+    # Python 2
+    try:
+        from cStringIO import StringIO
+    except ImportError:
+        from StringIO import StringIO
+
+try:
+    # Python 3.4
+    from contextlib import redirect_stdout
+except ImportError:
+    @contextmanager
+    def redirect_stdout(target):
+        original = sys.stdout
+        sys.stdout = target
+        yield
+        sys.stdout = original
+
+try:
+    # Python 3.5
+    from contextlib import redirect_stderr
+except ImportError:
+    @contextmanager
+    def redirect_stderr(target):
+        original = sys.stderr
+        sys.stderr = target
+        yield
+        sys.stderr = original
+
+
+def test_captured(capsys):
+    msg = "I've been redirected to Python, I hope!"
+    m.captured_output(msg)
+    stdout, stderr = capsys.readouterr()
+    assert stdout == msg
+    assert stderr == ''
+
+    m.captured_output_default(msg)
+    stdout, stderr = capsys.readouterr()
+    assert stdout == msg
+    assert stderr == ''
+
+    m.captured_err(msg)
+    stdout, stderr = capsys.readouterr()
+    assert stdout == ''
+    assert stderr == msg
+
+
+def test_guard_capture(capsys):
+    msg = "I've been redirected to Python, I hope!"
+    m.guard_output(msg)
+    stdout, stderr = capsys.readouterr()
+    assert stdout == msg
+    assert stderr == ''
+
+
+def test_series_captured(capture):
+    with capture:
+        m.captured_output("a")
+        m.captured_output("b")
+    assert capture == "ab"
+
+
+def test_flush(capfd):
+    msg = "(not flushed)"
+    msg2 = "(flushed)"
+
+    with m.ostream_redirect():
+        m.noisy_function(msg, flush=False)
+        stdout, stderr = capfd.readouterr()
+        assert stdout == ''
+
+        m.noisy_function(msg2, flush=True)
+        stdout, stderr = capfd.readouterr()
+        assert stdout == msg + msg2
+
+        m.noisy_function(msg, flush=False)
+
+    stdout, stderr = capfd.readouterr()
+    assert stdout == msg
+
+
+def test_not_captured(capfd):
+    msg = "Something that should not show up in log"
+    stream = StringIO()
+    with redirect_stdout(stream):
+        m.raw_output(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == msg
+    assert stderr == ''
+    assert stream.getvalue() == ''
+
+    stream = StringIO()
+    with redirect_stdout(stream):
+        m.captured_output(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == ''
+    assert stderr == ''
+    assert stream.getvalue() == msg
+
+
+def test_err(capfd):
+    msg = "Something that should not show up in log"
+    stream = StringIO()
+    with redirect_stderr(stream):
+        m.raw_err(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == ''
+    assert stderr == msg
+    assert stream.getvalue() == ''
+
+    stream = StringIO()
+    with redirect_stderr(stream):
+        m.captured_err(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == ''
+    assert stderr == ''
+    assert stream.getvalue() == msg
+
+
+def test_multi_captured(capfd):
+    stream = StringIO()
+    with redirect_stdout(stream):
+        m.captured_output("a")
+        m.raw_output("b")
+        m.captured_output("c")
+        m.raw_output("d")
+    stdout, stderr = capfd.readouterr()
+    assert stdout == 'bd'
+    assert stream.getvalue() == 'ac'
+
+
+def test_dual(capsys):
+    m.captured_dual("a", "b")
+    stdout, stderr = capsys.readouterr()
+    assert stdout == "a"
+    assert stderr == "b"
+
+
+def test_redirect(capfd):
+    msg = "Should not be in log!"
+    stream = StringIO()
+    with redirect_stdout(stream):
+        m.raw_output(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == msg
+    assert stream.getvalue() == ''
+
+    stream = StringIO()
+    with redirect_stdout(stream):
+        with m.ostream_redirect():
+            m.raw_output(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == ''
+    assert stream.getvalue() == msg
+
+    stream = StringIO()
+    with redirect_stdout(stream):
+        m.raw_output(msg)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == msg
+    assert stream.getvalue() == ''
+
+
+def test_redirect_err(capfd):
+    msg = "StdOut"
+    msg2 = "StdErr"
+
+    stream = StringIO()
+    with redirect_stderr(stream):
+        with m.ostream_redirect(stdout=False):
+            m.raw_output(msg)
+            m.raw_err(msg2)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == msg
+    assert stderr == ''
+    assert stream.getvalue() == msg2
+
+
+def test_redirect_both(capfd):
+    msg = "StdOut"
+    msg2 = "StdErr"
+
+    stream = StringIO()
+    stream2 = StringIO()
+    with redirect_stdout(stream):
+        with redirect_stderr(stream2):
+            with m.ostream_redirect():
+                m.raw_output(msg)
+                m.raw_err(msg2)
+    stdout, stderr = capfd.readouterr()
+    assert stdout == ''
+    assert stderr == ''
+    assert stream.getvalue() == msg
+    assert stream2.getvalue() == msg2
diff --git a/ext/pybind11/tests/test_issues.cpp b/ext/pybind11/tests/test_issues.cpp
deleted file mode 100644
index 7da370045..000000000
--- a/ext/pybind11/tests/test_issues.cpp
+++ /dev/null
@@ -1,400 +0,0 @@
-/*
-    tests/test_issues.cpp -- collection of testcases for miscellaneous issues
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-#include "constructor_stats.h"
-#include <pybind11/stl.h>
-#include <pybind11/operators.h>
-#include <pybind11/complex.h>
-
-#define TRACKERS(CLASS) CLASS() { print_default_created(this); } ~CLASS() { print_destroyed(this); }
-struct NestABase { int value = -2; TRACKERS(NestABase) };
-struct NestA : NestABase { int value = 3; NestA& operator+=(int i) { value += i; return *this; } TRACKERS(NestA) };
-struct NestB { NestA a; int value = 4; NestB& operator-=(int i) { value -= i; return *this; } TRACKERS(NestB) };
-struct NestC { NestB b; int value = 5; NestC& operator*=(int i) { value *= i; return *this; } TRACKERS(NestC) };
-
-/// #393
-class OpTest1 {};
-class OpTest2 {};
-
-OpTest1 operator+(const OpTest1 &, const OpTest1 &) {
-    py::print("Add OpTest1 with OpTest1");
-    return OpTest1();
-}
-OpTest2 operator+(const OpTest2 &, const OpTest2 &) {
-    py::print("Add OpTest2 with OpTest2");
-    return OpTest2();
-}
-OpTest2 operator+(const OpTest2 &, const OpTest1 &) {
-    py::print("Add OpTest2 with OpTest1");
-    return OpTest2();
-}
-
-// #461
-class Dupe1 {
-public:
-    Dupe1(int v) : v_{v} {}
-    int get_value() const { return v_; }
-private:
-    int v_;
-};
-class Dupe2 {};
-class Dupe3 {};
-class DupeException : public std::runtime_error {};
-
-// #478
-template <typename T> class custom_unique_ptr {
-public:
-    custom_unique_ptr() { print_default_created(this); }
-    custom_unique_ptr(T *ptr) : _ptr{ptr} { print_created(this, ptr); }
-    custom_unique_ptr(custom_unique_ptr<T> &&move) : _ptr{move._ptr} { move._ptr = nullptr; print_move_created(this); }
-    custom_unique_ptr &operator=(custom_unique_ptr<T> &&move) { print_move_assigned(this); if (_ptr) destruct_ptr(); _ptr = move._ptr; move._ptr = nullptr; return *this; }
-    custom_unique_ptr(const custom_unique_ptr<T> &) = delete;
-    void operator=(const custom_unique_ptr<T> &copy) = delete;
-    ~custom_unique_ptr() { print_destroyed(this); if (_ptr) destruct_ptr(); }
-private:
-    T *_ptr = nullptr;
-    void destruct_ptr() { delete _ptr; }
-};
-PYBIND11_DECLARE_HOLDER_TYPE(T, custom_unique_ptr<T>);
-
-/// Issue #528: templated constructor
-struct TplConstrClass {
-    template <typename T> TplConstrClass(const T &arg) : str{arg} {}
-    std::string str;
-    bool operator==(const TplConstrClass &t) const { return t.str == str; }
-};
-namespace std {
-template <> struct hash<TplConstrClass> { size_t operator()(const TplConstrClass &t) const { return std::hash<std::string>()(t.str); } };
-}
-
-void init_issues(py::module &m) {
-    py::module m2 = m.def_submodule("issues");
-
-#if !defined(_MSC_VER)
-    // Visual Studio 2015 currently cannot compile this test
-    // (see the comment in type_caster_base::make_copy_constructor)
-    // #70 compilation issue if operator new is not public
-    class NonConstructible { private: void *operator new(size_t bytes) throw(); };
-    py::class_<NonConstructible>(m, "Foo");
-    m2.def("getstmt", []() -> NonConstructible * { return nullptr; },
-        py::return_value_policy::reference);
-#endif
-
-    // #137: const char* isn't handled properly
-    m2.def("print_cchar", [](const char *s) { return std::string(s); });
-
-    // #150: char bindings broken
-    m2.def("print_char", [](char c) { return std::string(1, c); });
-
-    // #159: virtual function dispatch has problems with similar-named functions
-    struct Base { virtual std::string dispatch() const {
-        /* for some reason MSVC2015 can't compile this if the function is pure virtual */
-        return {};
-    }; };
-
-    struct DispatchIssue : Base {
-        virtual std::string dispatch() const {
-            PYBIND11_OVERLOAD_PURE(std::string, Base, dispatch, /* no arguments */);
-        }
-    };
-
-    py::class_<Base, DispatchIssue>(m2, "DispatchIssue")
-        .def(py::init<>())
-        .def("dispatch", &Base::dispatch);
-
-    m2.def("dispatch_issue_go", [](const Base * b) { return b->dispatch(); });
-
-    struct Placeholder { int i; Placeholder(int i) : i(i) { } };
-
-    py::class_<Placeholder>(m2, "Placeholder")
-        .def(py::init<int>())
-        .def("__repr__", [](const Placeholder &p) { return "Placeholder[" + std::to_string(p.i) + "]"; });
-
-    // #171: Can't return reference wrappers (or STL datastructures containing them)
-    m2.def("return_vec_of_reference_wrapper", [](std::reference_wrapper<Placeholder> p4) {
-        Placeholder *p1 = new Placeholder{1};
-        Placeholder *p2 = new Placeholder{2};
-        Placeholder *p3 = new Placeholder{3};
-        std::vector<std::reference_wrapper<Placeholder>> v;
-        v.push_back(std::ref(*p1));
-        v.push_back(std::ref(*p2));
-        v.push_back(std::ref(*p3));
-        v.push_back(p4);
-        return v;
-    });
-
-    // #181: iterator passthrough did not compile
-    m2.def("iterator_passthrough", [](py::iterator s) -> py::iterator {
-        return py::make_iterator(std::begin(s), std::end(s));
-    });
-
-    // #187: issue involving std::shared_ptr<> return value policy & garbage collection
-    struct ElementBase { virtual void foo() { } /* Force creation of virtual table */ };
-    struct ElementA : ElementBase {
-        ElementA(int v) : v(v) { }
-        int value() { return v; }
-        int v;
-    };
-
-    struct ElementList {
-        void add(std::shared_ptr<ElementBase> e) { l.push_back(e); }
-        std::vector<std::shared_ptr<ElementBase>> l;
-    };
-
-    py::class_<ElementBase, std::shared_ptr<ElementBase>> (m2, "ElementBase");
-
-    py::class_<ElementA, ElementBase, std::shared_ptr<ElementA>>(m2, "ElementA")
-        .def(py::init<int>())
-        .def("value", &ElementA::value);
-
-    py::class_<ElementList, std::shared_ptr<ElementList>>(m2, "ElementList")
-        .def(py::init<>())
-        .def("add", &ElementList::add)
-        .def("get", [](ElementList &el) {
-            py::list list;
-            for (auto &e : el.l)
-                list.append(py::cast(e));
-            return list;
-        });
-
-    // (no id): should not be able to pass 'None' to a reference argument
-    m2.def("get_element", [](ElementA &el) { return el.value(); });
-
-    // (no id): don't cast doubles to ints
-    m2.def("expect_float", [](float f) { return f; });
-    m2.def("expect_int", [](int i) { return i; });
-
-    try {
-        py::class_<Placeholder>(m2, "Placeholder");
-        throw std::logic_error("Expected an exception!");
-    } catch (std::runtime_error &) {
-        /* All good */
-    }
-
-    // Issue #283: __str__ called on uninitialized instance when constructor arguments invalid
-    class StrIssue {
-    public:
-        StrIssue(int i) : val{i} {}
-        StrIssue() : StrIssue(-1) {}
-        int value() const { return val; }
-    private:
-        int val;
-    };
-    py::class_<StrIssue> si(m2, "StrIssue");
-    si  .def(py::init<int>())
-        .def(py::init<>())
-        .def("__str__", [](const StrIssue &si) { return "StrIssue[" + std::to_string(si.value()) + "]"; })
-        ;
-
-    // Issue #328: first member in a class can't be used in operators
-    py::class_<NestABase>(m2, "NestABase").def(py::init<>()).def_readwrite("value", &NestABase::value);
-    py::class_<NestA>(m2, "NestA").def(py::init<>()).def(py::self += int())
-        .def("as_base", [](NestA &a) -> NestABase& { return (NestABase&) a; }, py::return_value_policy::reference_internal);
-    py::class_<NestB>(m2, "NestB").def(py::init<>()).def(py::self -= int()).def_readwrite("a", &NestB::a);
-    py::class_<NestC>(m2, "NestC").def(py::init<>()).def(py::self *= int()).def_readwrite("b", &NestC::b);
-    m2.def("get_NestA", [](const NestA &a) { return a.value; });
-    m2.def("get_NestB", [](const NestB &b) { return b.value; });
-    m2.def("get_NestC", [](const NestC &c) { return c.value; });
-
-    // Issue 389: r_v_p::move should fall-through to copy on non-movable objects
-    class MoveIssue1 {
-    public:
-        MoveIssue1(int v) : v{v} {}
-        MoveIssue1(const MoveIssue1 &c) { v = c.v; }
-        MoveIssue1(MoveIssue1 &&) = delete;
-        int v;
-    };
-    class MoveIssue2 {
-    public:
-        MoveIssue2(int v) : v{v} {}
-        MoveIssue2(MoveIssue2 &&) = default;
-        int v;
-    };
-    py::class_<MoveIssue1>(m2, "MoveIssue1").def(py::init<int>()).def_readwrite("value", &MoveIssue1::v);
-    py::class_<MoveIssue2>(m2, "MoveIssue2").def(py::init<int>()).def_readwrite("value", &MoveIssue2::v);
-    m2.def("get_moveissue1", [](int i) -> MoveIssue1 * { return new MoveIssue1(i); }, py::return_value_policy::move);
-    m2.def("get_moveissue2", [](int i) { return MoveIssue2(i); }, py::return_value_policy::move);
-
-    // Issues 392/397: overridding reference-returning functions
-    class OverrideTest {
-    public:
-        struct A { std::string value = "hi"; };
-        std::string v;
-        A a;
-        explicit OverrideTest(const std::string &v) : v{v} {}
-        virtual std::string str_value() { return v; }
-        virtual std::string &str_ref() { return v; }
-        virtual A A_value() { return a; }
-        virtual A &A_ref() { return a; }
-    };
-    class PyOverrideTest : public OverrideTest {
-    public:
-        using OverrideTest::OverrideTest;
-        std::string str_value() override { PYBIND11_OVERLOAD(std::string, OverrideTest, str_value); }
-        // Not allowed (uncommenting should hit a static_assert failure): we can't get a reference
-        // to a python numeric value, since we only copy values in the numeric type caster:
-//      std::string &str_ref() override { PYBIND11_OVERLOAD(std::string &, OverrideTest, str_ref); }
-        // But we can work around it like this:
-    private:
-        std::string _tmp;
-        std::string str_ref_helper() { PYBIND11_OVERLOAD(std::string, OverrideTest, str_ref); }
-    public:
-        std::string &str_ref() override { return _tmp = str_ref_helper(); }
-
-        A A_value() override { PYBIND11_OVERLOAD(A, OverrideTest, A_value); }
-        A &A_ref() override { PYBIND11_OVERLOAD(A &, OverrideTest, A_ref); }
-    };
-    py::class_<OverrideTest::A>(m2, "OverrideTest_A")
-        .def_readwrite("value", &OverrideTest::A::value);
-    py::class_<OverrideTest, PyOverrideTest>(m2, "OverrideTest")
-        .def(py::init<const std::string &>())
-        .def("str_value", &OverrideTest::str_value)
-//      .def("str_ref", &OverrideTest::str_ref)
-        .def("A_value", &OverrideTest::A_value)
-        .def("A_ref", &OverrideTest::A_ref);
-
-    /// Issue 393: need to return NotSupported to ensure correct arithmetic operator behavior
-    py::class_<OpTest1>(m2, "OpTest1")
-        .def(py::init<>())
-        .def(py::self + py::self);
-
-    py::class_<OpTest2>(m2, "OpTest2")
-        .def(py::init<>())
-        .def(py::self + py::self)
-        .def("__add__", [](const OpTest2& c2, const OpTest1& c1) { return c2 + c1; })
-        .def("__radd__", [](const OpTest2& c2, const OpTest1& c1) { return c2 + c1; });
-
-    // Issue 388: Can't make iterators via make_iterator() with different r/v policies
-    static std::vector<int> list = { 1, 2, 3 };
-    m2.def("make_iterator_1", []() { return py::make_iterator<py::return_value_policy::copy>(list); });
-    m2.def("make_iterator_2", []() { return py::make_iterator<py::return_value_policy::automatic>(list); });
-
-    static std::vector<std::string> nothrows;
-    // Issue 461: registering two things with the same name:
-    py::class_<Dupe1>(m2, "Dupe1")
-        .def("get_value", &Dupe1::get_value)
-        ;
-    m2.def("dupe1_factory", [](int v) { return new Dupe1(v); });
-
-    py::class_<Dupe2>(m2, "Dupe2");
-    py::exception<DupeException>(m2, "DupeException");
-
-    try {
-        m2.def("Dupe1", [](int v) { return new Dupe1(v); });
-        nothrows.emplace_back("Dupe1");
-    }
-    catch (std::runtime_error &) {}
-    try {
-        py::class_<Dupe3>(m2, "dupe1_factory");
-        nothrows.emplace_back("dupe1_factory");
-    }
-    catch (std::runtime_error &) {}
-    try {
-        py::exception<Dupe3>(m2, "Dupe2");
-        nothrows.emplace_back("Dupe2");
-    }
-    catch (std::runtime_error &) {}
-    try {
-        m2.def("DupeException", []() { return 30; });
-        nothrows.emplace_back("DupeException1");
-    }
-    catch (std::runtime_error &) {}
-    try {
-        py::class_<DupeException>(m2, "DupeException");
-        nothrows.emplace_back("DupeException2");
-    }
-    catch (std::runtime_error &) {}
-    m2.def("dupe_exception_failures", []() {
-        py::list l;
-        for (auto &e : nothrows) l.append(py::cast(e));
-        return l;
-    });
-
-    /// Issue #471: shared pointer instance not dellocated
-    class SharedChild : public std::enable_shared_from_this<SharedChild> {
-    public:
-        SharedChild() { print_created(this); }
-        ~SharedChild() { print_destroyed(this); }
-    };
-
-    class SharedParent {
-    public:
-        SharedParent() : child(std::make_shared<SharedChild>()) { }
-        const SharedChild &get_child() const { return *child; }
-
-    private:
-        std::shared_ptr<SharedChild> child;
-    };
-
-    py::class_<SharedChild, std::shared_ptr<SharedChild>>(m, "SharedChild");
-    py::class_<SharedParent, std::shared_ptr<SharedParent>>(m, "SharedParent")
-        .def(py::init<>())
-        .def("get_child", &SharedParent::get_child, py::return_value_policy::reference);
-
-    /// Issue/PR #478: unique ptrs constructed and freed without destruction
-    class SpecialHolderObj {
-    public:
-        int val = 0;
-        SpecialHolderObj *ch = nullptr;
-        SpecialHolderObj(int v, bool make_child = true) : val{v}, ch{make_child ? new SpecialHolderObj(val+1, false) : nullptr}
-        { print_created(this, val); }
-        ~SpecialHolderObj() { delete ch; print_destroyed(this); }
-        SpecialHolderObj *child() { return ch; }
-    };
-
-    py::class_<SpecialHolderObj, custom_unique_ptr<SpecialHolderObj>>(m, "SpecialHolderObj")
-        .def(py::init<int>())
-        .def("child", &SpecialHolderObj::child, pybind11::return_value_policy::reference_internal)
-        .def_readwrite("val", &SpecialHolderObj::val)
-        .def_static("holder_cstats", &ConstructorStats::get<custom_unique_ptr<SpecialHolderObj>>,
-                py::return_value_policy::reference);
-
-    /// Issue #484: number conversion generates unhandled exceptions
-    m2.def("test_complex", [](float x) { py::print("{}"_s.format(x)); });
-    m2.def("test_complex", [](std::complex<float> x) { py::print("({}, {})"_s.format(x.real(), x.imag())); });
-
-    /// Issue #511: problem with inheritance + overwritten def_static
-    struct MyBase {
-        static std::unique_ptr<MyBase> make() {
-            return std::unique_ptr<MyBase>(new MyBase());
-        }
-    };
-
-    struct MyDerived : MyBase {
-        static std::unique_ptr<MyDerived> make() {
-            return std::unique_ptr<MyDerived>(new MyDerived());
-        }
-    };
-
-    py::class_<MyBase>(m2, "MyBase")
-        .def_static("make", &MyBase::make);
-
-    py::class_<MyDerived, MyBase>(m2, "MyDerived")
-        .def_static("make", &MyDerived::make)
-        .def_static("make2", &MyDerived::make);
-
-    py::dict d;
-    std::string bar = "bar";
-    d["str"] = bar;
-    d["num"] = 3.7;
-
-    /// Issue #528: templated constructor
-    m2.def("tpl_constr_vector", [](std::vector<TplConstrClass> &) {});
-    m2.def("tpl_constr_map", [](std::unordered_map<TplConstrClass, TplConstrClass> &) {});
-    m2.def("tpl_constr_set", [](std::unordered_set<TplConstrClass> &) {});
-#if defined(PYBIND11_HAS_OPTIONAL)
-    m2.def("tpl_constr_optional", [](std::optional<TplConstrClass> &) {});
-#elif defined(PYBIND11_HAS_EXP_OPTIONAL)
-    m2.def("tpl_constr_optional", [](std::experimental::optional<TplConstrClass> &) {});
-#endif
-}
-
-// MSVC workaround: trying to use a lambda here crashes MSVC
-test_initializer issues(&init_issues);
diff --git a/ext/pybind11/tests/test_issues.py b/ext/pybind11/tests/test_issues.py
deleted file mode 100644
index e60b5ca90..000000000
--- a/ext/pybind11/tests/test_issues.py
+++ /dev/null
@@ -1,251 +0,0 @@
-import pytest
-from pybind11_tests import ConstructorStats
-
-
-def test_regressions():
-    from pybind11_tests.issues import print_cchar, print_char
-
-    # #137: const char* isn't handled properly
-    assert print_cchar("const char *") == "const char *"
-    # #150: char bindings broken
-    assert print_char("c") == "c"
-
-
-def test_dispatch_issue(msg):
-    """#159: virtual function dispatch has problems with similar-named functions"""
-    from pybind11_tests.issues import DispatchIssue, dispatch_issue_go
-
-    class PyClass1(DispatchIssue):
-        def dispatch(self):
-            return "Yay.."
-
-    class PyClass2(DispatchIssue):
-        def dispatch(self):
-            with pytest.raises(RuntimeError) as excinfo:
-                super(PyClass2, self).dispatch()
-            assert msg(excinfo.value) == 'Tried to call pure virtual function "Base::dispatch"'
-
-            p = PyClass1()
-            return dispatch_issue_go(p)
-
-    b = PyClass2()
-    assert dispatch_issue_go(b) == "Yay.."
-
-
-def test_reference_wrapper():
-    """#171: Can't return reference wrappers (or STL data structures containing them)"""
-    from pybind11_tests.issues import Placeholder, return_vec_of_reference_wrapper
-
-    assert str(return_vec_of_reference_wrapper(Placeholder(4))) == \
-        "[Placeholder[1], Placeholder[2], Placeholder[3], Placeholder[4]]"
-
-
-def test_iterator_passthrough():
-    """#181: iterator passthrough did not compile"""
-    from pybind11_tests.issues import iterator_passthrough
-
-    assert list(iterator_passthrough(iter([3, 5, 7, 9, 11, 13, 15]))) == [3, 5, 7, 9, 11, 13, 15]
-
-
-def test_shared_ptr_gc():
-    """// #187: issue involving std::shared_ptr<> return value policy & garbage collection"""
-    from pybind11_tests.issues import ElementList, ElementA
-
-    el = ElementList()
-    for i in range(10):
-        el.add(ElementA(i))
-    pytest.gc_collect()
-    for i, v in enumerate(el.get()):
-        assert i == v.value()
-
-
-def test_no_id(msg):
-    from pybind11_tests.issues import get_element, expect_float, expect_int
-
-    with pytest.raises(TypeError) as excinfo:
-        get_element(None)
-    assert msg(excinfo.value) == """
-        get_element(): incompatible function arguments. The following argument types are supported:
-            1. (arg0: m.issues.ElementA) -> int
-
-        Invoked with: None
-    """
-
-    with pytest.raises(TypeError) as excinfo:
-        expect_int(5.2)
-    assert msg(excinfo.value) == """
-        expect_int(): incompatible function arguments. The following argument types are supported:
-            1. (arg0: int) -> int
-
-        Invoked with: 5.2
-    """
-    assert expect_float(12) == 12
-
-
-def test_str_issue(msg):
-    """Issue #283: __str__ called on uninitialized instance when constructor arguments invalid"""
-    from pybind11_tests.issues import StrIssue
-
-    assert str(StrIssue(3)) == "StrIssue[3]"
-
-    with pytest.raises(TypeError) as excinfo:
-        str(StrIssue("no", "such", "constructor"))
-    assert msg(excinfo.value) == """
-        __init__(): incompatible constructor arguments. The following argument types are supported:
-            1. m.issues.StrIssue(arg0: int)
-            2. m.issues.StrIssue()
-
-        Invoked with: 'no', 'such', 'constructor'
-    """
-
-
-def test_nested():
-    """ #328: first member in a class can't be used in operators"""
-    from pybind11_tests.issues import NestA, NestB, NestC, get_NestA, get_NestB, get_NestC
-
-    a = NestA()
-    b = NestB()
-    c = NestC()
-
-    a += 10
-    assert get_NestA(a) == 13
-    b.a += 100
-    assert get_NestA(b.a) == 103
-    c.b.a += 1000
-    assert get_NestA(c.b.a) == 1003
-    b -= 1
-    assert get_NestB(b) == 3
-    c.b -= 3
-    assert get_NestB(c.b) == 1
-    c *= 7
-    assert get_NestC(c) == 35
-
-    abase = a.as_base()
-    assert abase.value == -2
-    a.as_base().value += 44
-    assert abase.value == 42
-    assert c.b.a.as_base().value == -2
-    c.b.a.as_base().value += 44
-    assert c.b.a.as_base().value == 42
-
-    del c
-    pytest.gc_collect()
-    del a  # Should't delete while abase is still alive
-    pytest.gc_collect()
-
-    assert abase.value == 42
-    del abase, b
-    pytest.gc_collect()
-
-
-def test_move_fallback():
-    from pybind11_tests.issues import get_moveissue1, get_moveissue2
-    m2 = get_moveissue2(2)
-    assert m2.value == 2
-    m1 = get_moveissue1(1)
-    assert m1.value == 1
-
-
-def test_override_ref():
-    from pybind11_tests.issues import OverrideTest
-    o = OverrideTest("asdf")
-
-    # Not allowed (see associated .cpp comment)
-    # i = o.str_ref()
-    # assert o.str_ref() == "asdf"
-    assert o.str_value() == "asdf"
-
-    assert o.A_value().value == "hi"
-    a = o.A_ref()
-    assert a.value == "hi"
-    a.value = "bye"
-    assert a.value == "bye"
-
-
-def test_operators_notimplemented(capture):
-    from pybind11_tests.issues import OpTest1, OpTest2
-    with capture:
-        c1, c2 = OpTest1(), OpTest2()
-        c1 + c1
-        c2 + c2
-        c2 + c1
-        c1 + c2
-    assert capture == """
-        Add OpTest1 with OpTest1
-        Add OpTest2 with OpTest2
-        Add OpTest2 with OpTest1
-        Add OpTest2 with OpTest1
-    """
-
-
-def test_iterator_rvpolicy():
-    """ Issue 388: Can't make iterators via make_iterator() with different r/v policies """
-    from pybind11_tests.issues import make_iterator_1
-    from pybind11_tests.issues import make_iterator_2
-
-    assert list(make_iterator_1()) == [1, 2, 3]
-    assert list(make_iterator_2()) == [1, 2, 3]
-    assert not isinstance(make_iterator_1(), type(make_iterator_2()))
-
-
-def test_dupe_assignment():
-    """ Issue 461: overwriting a class with a function """
-    from pybind11_tests.issues import dupe_exception_failures
-    assert dupe_exception_failures() == []
-
-
-def test_enable_shared_from_this_with_reference_rvp():
-    """ Issue #471: shared pointer instance not dellocated """
-    from pybind11_tests import SharedParent, SharedChild
-
-    parent = SharedParent()
-    child = parent.get_child()
-
-    cstats = ConstructorStats.get(SharedChild)
-    assert cstats.alive() == 1
-    del child, parent
-    assert cstats.alive() == 0
-
-
-def test_non_destructed_holders():
-    """ Issue #478: unique ptrs constructed and freed without destruction """
-    from pybind11_tests import SpecialHolderObj
-
-    a = SpecialHolderObj(123)
-    b = a.child()
-
-    assert a.val == 123
-    assert b.val == 124
-
-    cstats = SpecialHolderObj.holder_cstats()
-    assert cstats.alive() == 1
-    del b
-    assert cstats.alive() == 1
-    del a
-    assert cstats.alive() == 0
-
-
-def test_complex_cast(capture):
-    """ Issue #484: number conversion generates unhandled exceptions """
-    from pybind11_tests.issues import test_complex
-
-    with capture:
-        test_complex(1)
-        test_complex(2j)
-
-    assert capture == """
-        1.0
-        (0.0, 2.0)
-    """
-
-
-def test_inheritance_override_def_static():
-    from pybind11_tests.issues import MyBase, MyDerived
-
-    b = MyBase.make()
-    d1 = MyDerived.make2()
-    d2 = MyDerived.make()
-
-    assert isinstance(b, MyBase)
-    assert isinstance(d1, MyDerived)
-    assert isinstance(d2, MyDerived)
diff --git a/ext/pybind11/tests/test_keep_alive.cpp b/ext/pybind11/tests/test_keep_alive.cpp
deleted file mode 100644
index cd62a02e8..000000000
--- a/ext/pybind11/tests/test_keep_alive.cpp
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
-    tests/test_keep_alive.cpp -- keep_alive modifier (pybind11's version
-    of Boost.Python's with_custodian_and_ward / with_custodian_and_ward_postcall)
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-class Child {
-public:
-    Child() { py::print("Allocating child."); }
-    ~Child() { py::print("Releasing child."); }
-};
-
-class Parent {
-public:
-    Parent() { py::print("Allocating parent."); }
-    ~Parent() { py::print("Releasing parent."); }
-    void addChild(Child *) { }
-    Child *returnChild() { return new Child(); }
-    Child *returnNullChild() { return nullptr; }
-};
-
-test_initializer keep_alive([](py::module &m) {
-    py::class_<Parent>(m, "Parent")
-        .def(py::init<>())
-        .def("addChild", &Parent::addChild)
-        .def("addChildKeepAlive", &Parent::addChild, py::keep_alive<1, 2>())
-        .def("returnChild", &Parent::returnChild)
-        .def("returnChildKeepAlive", &Parent::returnChild, py::keep_alive<1, 0>())
-        .def("returnNullChildKeepAliveChild", &Parent::returnNullChild, py::keep_alive<1, 0>())
-        .def("returnNullChildKeepAliveParent", &Parent::returnNullChild, py::keep_alive<0, 1>());
-
-    py::class_<Child>(m, "Child")
-        .def(py::init<>());
-});
diff --git a/ext/pybind11/tests/test_keep_alive.py b/ext/pybind11/tests/test_keep_alive.py
deleted file mode 100644
index bfd7d40c3..000000000
--- a/ext/pybind11/tests/test_keep_alive.py
+++ /dev/null
@@ -1,97 +0,0 @@
-import pytest
-
-
-def test_keep_alive_argument(capture):
-    from pybind11_tests import Parent, Child
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.addChild(Child())
-        pytest.gc_collect()
-    assert capture == """
-        Allocating child.
-        Releasing child.
-    """
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == "Releasing parent."
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.addChildKeepAlive(Child())
-        pytest.gc_collect()
-    assert capture == "Allocating child."
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == """
-        Releasing parent.
-        Releasing child.
-    """
-
-
-def test_keep_alive_return_value(capture):
-    from pybind11_tests import Parent
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.returnChild()
-        pytest.gc_collect()
-    assert capture == """
-        Allocating child.
-        Releasing child.
-    """
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == "Releasing parent."
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.returnChildKeepAlive()
-        pytest.gc_collect()
-    assert capture == "Allocating child."
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == """
-        Releasing parent.
-        Releasing child.
-    """
-
-
-def test_return_none(capture):
-    from pybind11_tests import Parent
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.returnNullChildKeepAliveChild()
-        pytest.gc_collect()
-    assert capture == ""
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == "Releasing parent."
-
-    with capture:
-        p = Parent()
-    assert capture == "Allocating parent."
-    with capture:
-        p.returnNullChildKeepAliveParent()
-        pytest.gc_collect()
-    assert capture == ""
-    with capture:
-        del p
-        pytest.gc_collect()
-    assert capture == "Releasing parent."
diff --git a/ext/pybind11/tests/test_kwargs_and_defaults.cpp b/ext/pybind11/tests/test_kwargs_and_defaults.cpp
index 3180123df..165f8017e 100644
--- a/ext/pybind11/tests/test_kwargs_and_defaults.cpp
+++ b/ext/pybind11/tests/test_kwargs_and_defaults.cpp
@@ -10,84 +10,62 @@
 #include "pybind11_tests.h"
 #include <pybind11/stl.h>
 
-std::string kw_func(int x, int y) { return "x=" + std::to_string(x) + ", y=" + std::to_string(y); }
+TEST_SUBMODULE(kwargs_and_defaults, m) {
+    auto kw_func = [](int x, int y) { return "x=" + std::to_string(x) + ", y=" + std::to_string(y); };
 
-std::string kw_func4(const std::vector<int> &entries) {
-    std::string ret = "{";
-    for (int i : entries)
-        ret += std::to_string(i) + " ";
-    ret.back() = '}';
-    return ret;
-}
-
-py::tuple args_function(py::args args) {
-    return args;
-}
-
-py::tuple args_kwargs_function(py::args args, py::kwargs kwargs) {
-    return py::make_tuple(args, kwargs);
-}
-
-py::tuple mixed_plus_args(int i, double j, py::args args) {
-    return py::make_tuple(i, j, args);
-}
-
-py::tuple mixed_plus_kwargs(int i, double j, py::kwargs kwargs) {
-    return py::make_tuple(i, j, kwargs);
-}
-
-py::tuple mixed_plus_args_kwargs(int i, double j, py::args args, py::kwargs kwargs) {
-    return py::make_tuple(i, j, args, kwargs);
-}
-
-// pybind11 won't allow these to be bound: args and kwargs, if present, must be at the end.
-void bad_args1(py::args, int) {}
-void bad_args2(py::kwargs, int) {}
-void bad_args3(py::kwargs, py::args) {}
-void bad_args4(py::args, int, py::kwargs) {}
-void bad_args5(py::args, py::kwargs, int) {}
-void bad_args6(py::args, py::args) {}
-void bad_args7(py::kwargs, py::kwargs) {}
-
-struct KWClass {
-    void foo(int, float) {}
-};
-
-test_initializer arg_keywords_and_defaults([](py::module &m) {
-    m.def("kw_func0", &kw_func);
-    m.def("kw_func1", &kw_func, py::arg("x"), py::arg("y"));
-    m.def("kw_func2", &kw_func, py::arg("x") = 100, py::arg("y") = 200);
+    // test_named_arguments
+    m.def("kw_func0", kw_func);
+    m.def("kw_func1", kw_func, py::arg("x"), py::arg("y"));
+    m.def("kw_func2", kw_func, py::arg("x") = 100, py::arg("y") = 200);
     m.def("kw_func3", [](const char *) { }, py::arg("data") = std::string("Hello world!"));
 
     /* A fancier default argument */
-    std::vector<int> list;
-    list.push_back(13);
-    list.push_back(17);
-    m.def("kw_func4", &kw_func4, py::arg("myList") = list);
-
-    m.def("args_function", &args_function);
-    m.def("args_kwargs_function", &args_kwargs_function);
-
-    m.def("kw_func_udl", &kw_func, "x"_a, "y"_a=300);
-    m.def("kw_func_udl_z", &kw_func, "x"_a, "y"_a=0);
+    std::vector<int> list{{13, 17}};
+    m.def("kw_func4", [](const std::vector<int> &entries) {
+        std::string ret = "{";
+        for (int i : entries)
+            ret += std::to_string(i) + " ";
+        ret.back() = '}';
+        return ret;
+    }, py::arg("myList") = list);
+
+    m.def("kw_func_udl", kw_func, "x"_a, "y"_a=300);
+    m.def("kw_func_udl_z", kw_func, "x"_a, "y"_a=0);
+
+    // test_args_and_kwargs
+    m.def("args_function", [](py::args args) -> py::tuple { return args; });
+    m.def("args_kwargs_function", [](py::args args, py::kwargs kwargs) {
+        return py::make_tuple(args, kwargs);
+    });
+
+    // test_mixed_args_and_kwargs
+    m.def("mixed_plus_args", [](int i, double j, py::args args) {
+        return py::make_tuple(i, j, args);
+    });
+    m.def("mixed_plus_kwargs", [](int i, double j, py::kwargs kwargs) {
+        return py::make_tuple(i, j, kwargs);
+    });
+    auto mixed_plus_both = [](int i, double j, py::args args, py::kwargs kwargs) {
+        return py::make_tuple(i, j, args, kwargs);
+    };
+    m.def("mixed_plus_args_kwargs", mixed_plus_both);
+
+    m.def("mixed_plus_args_kwargs_defaults", mixed_plus_both,
+            py::arg("i") = 1, py::arg("j") = 3.14159);
 
+    // pybind11 won't allow these to be bound: args and kwargs, if present, must be at the end.
+    // Uncomment these to test that the static_assert is indeed working:
+//    m.def("bad_args1", [](py::args, int) {});
+//    m.def("bad_args2", [](py::kwargs, int) {});
+//    m.def("bad_args3", [](py::kwargs, py::args) {});
+//    m.def("bad_args4", [](py::args, int, py::kwargs) {});
+//    m.def("bad_args5", [](py::args, py::kwargs, int) {});
+//    m.def("bad_args6", [](py::args, py::args) {});
+//    m.def("bad_args7", [](py::kwargs, py::kwargs) {});
+
+    // test_function_signatures (along with most of the above)
+    struct KWClass { void foo(int, float) {} };
     py::class_<KWClass>(m, "KWClass")
         .def("foo0", &KWClass::foo)
         .def("foo1", &KWClass::foo, "x"_a, "y"_a);
-
-    m.def("mixed_plus_args", &mixed_plus_args);
-    m.def("mixed_plus_kwargs", &mixed_plus_kwargs);
-    m.def("mixed_plus_args_kwargs", &mixed_plus_args_kwargs);
-
-    m.def("mixed_plus_args_kwargs_defaults", &mixed_plus_args_kwargs,
-            py::arg("i") = 1, py::arg("j") = 3.14159);
-
-    // Uncomment these to test that the static_assert is indeed working:
-//    m.def("bad_args1", &bad_args1);
-//    m.def("bad_args2", &bad_args2);
-//    m.def("bad_args3", &bad_args3);
-//    m.def("bad_args4", &bad_args4);
-//    m.def("bad_args5", &bad_args5);
-//    m.def("bad_args6", &bad_args6);
-//    m.def("bad_args7", &bad_args7);
-});
+}
diff --git a/ext/pybind11/tests/test_kwargs_and_defaults.py b/ext/pybind11/tests/test_kwargs_and_defaults.py
index 90f8489ed..733fe8593 100644
--- a/ext/pybind11/tests/test_kwargs_and_defaults.py
+++ b/ext/pybind11/tests/test_kwargs_and_defaults.py
@@ -1,65 +1,64 @@
 import pytest
-from pybind11_tests import (kw_func0, kw_func1, kw_func2, kw_func3, kw_func4, args_function,
-                            args_kwargs_function, kw_func_udl, kw_func_udl_z, KWClass)
+from pybind11_tests import kwargs_and_defaults as m
 
 
 def test_function_signatures(doc):
-    assert doc(kw_func0) == "kw_func0(arg0: int, arg1: int) -> str"
-    assert doc(kw_func1) == "kw_func1(x: int, y: int) -> str"
-    assert doc(kw_func2) == "kw_func2(x: int=100, y: int=200) -> str"
-    assert doc(kw_func3) == "kw_func3(data: str='Hello world!') -> None"
-    assert doc(kw_func4) == "kw_func4(myList: List[int]=[13, 17]) -> str"
-    assert doc(kw_func_udl) == "kw_func_udl(x: int, y: int=300) -> str"
-    assert doc(kw_func_udl_z) == "kw_func_udl_z(x: int, y: int=0) -> str"
-    assert doc(args_function) == "args_function(*args) -> tuple"
-    assert doc(args_kwargs_function) == "args_kwargs_function(*args, **kwargs) -> tuple"
-    assert doc(KWClass.foo0) == "foo0(self: m.KWClass, arg0: int, arg1: float) -> None"
-    assert doc(KWClass.foo1) == "foo1(self: m.KWClass, x: int, y: float) -> None"
+    assert doc(m.kw_func0) == "kw_func0(arg0: int, arg1: int) -> str"
+    assert doc(m.kw_func1) == "kw_func1(x: int, y: int) -> str"
+    assert doc(m.kw_func2) == "kw_func2(x: int=100, y: int=200) -> str"
+    assert doc(m.kw_func3) == "kw_func3(data: str='Hello world!') -> None"
+    assert doc(m.kw_func4) == "kw_func4(myList: List[int]=[13, 17]) -> str"
+    assert doc(m.kw_func_udl) == "kw_func_udl(x: int, y: int=300) -> str"
+    assert doc(m.kw_func_udl_z) == "kw_func_udl_z(x: int, y: int=0) -> str"
+    assert doc(m.args_function) == "args_function(*args) -> tuple"
+    assert doc(m.args_kwargs_function) == "args_kwargs_function(*args, **kwargs) -> tuple"
+    assert doc(m.KWClass.foo0) == \
+        "foo0(self: m.kwargs_and_defaults.KWClass, arg0: int, arg1: float) -> None"
+    assert doc(m.KWClass.foo1) == \
+        "foo1(self: m.kwargs_and_defaults.KWClass, x: int, y: float) -> None"
 
 
 def test_named_arguments(msg):
-    assert kw_func0(5, 10) == "x=5, y=10"
+    assert m.kw_func0(5, 10) == "x=5, y=10"
 
-    assert kw_func1(5, 10) == "x=5, y=10"
-    assert kw_func1(5, y=10) == "x=5, y=10"
-    assert kw_func1(y=10, x=5) == "x=5, y=10"
+    assert m.kw_func1(5, 10) == "x=5, y=10"
+    assert m.kw_func1(5, y=10) == "x=5, y=10"
+    assert m.kw_func1(y=10, x=5) == "x=5, y=10"
 
-    assert kw_func2() == "x=100, y=200"
-    assert kw_func2(5) == "x=5, y=200"
-    assert kw_func2(x=5) == "x=5, y=200"
-    assert kw_func2(y=10) == "x=100, y=10"
-    assert kw_func2(5, 10) == "x=5, y=10"
-    assert kw_func2(x=5, y=10) == "x=5, y=10"
+    assert m.kw_func2() == "x=100, y=200"
+    assert m.kw_func2(5) == "x=5, y=200"
+    assert m.kw_func2(x=5) == "x=5, y=200"
+    assert m.kw_func2(y=10) == "x=100, y=10"
+    assert m.kw_func2(5, 10) == "x=5, y=10"
+    assert m.kw_func2(x=5, y=10) == "x=5, y=10"
 
     with pytest.raises(TypeError) as excinfo:
         # noinspection PyArgumentList
-        kw_func2(x=5, y=10, z=12)
+        m.kw_func2(x=5, y=10, z=12)
     assert excinfo.match(
         r'(?s)^kw_func2\(\): incompatible.*Invoked with: kwargs: ((x=5|y=10|z=12)(, |$))' + '{3}$')
 
-    assert kw_func4() == "{13 17}"
-    assert kw_func4(myList=[1, 2, 3]) == "{1 2 3}"
+    assert m.kw_func4() == "{13 17}"
+    assert m.kw_func4(myList=[1, 2, 3]) == "{1 2 3}"
 
-    assert kw_func_udl(x=5, y=10) == "x=5, y=10"
-    assert kw_func_udl_z(x=5) == "x=5, y=0"
+    assert m.kw_func_udl(x=5, y=10) == "x=5, y=10"
+    assert m.kw_func_udl_z(x=5) == "x=5, y=0"
 
 
 def test_arg_and_kwargs():
     args = 'arg1_value', 'arg2_value', 3
-    assert args_function(*args) == args
+    assert m.args_function(*args) == args
 
     args = 'a1', 'a2'
     kwargs = dict(arg3='a3', arg4=4)
-    assert args_kwargs_function(*args, **kwargs) == (args, kwargs)
+    assert m.args_kwargs_function(*args, **kwargs) == (args, kwargs)
 
 
 def test_mixed_args_and_kwargs(msg):
-    from pybind11_tests import (mixed_plus_args, mixed_plus_kwargs, mixed_plus_args_kwargs,
-                                mixed_plus_args_kwargs_defaults)
-    mpa = mixed_plus_args
-    mpk = mixed_plus_kwargs
-    mpak = mixed_plus_args_kwargs
-    mpakd = mixed_plus_args_kwargs_defaults
+    mpa = m.mixed_plus_args
+    mpk = m.mixed_plus_kwargs
+    mpak = m.mixed_plus_args_kwargs
+    mpakd = m.mixed_plus_args_kwargs_defaults
 
     assert mpa(1, 2.5, 4, 99.5, None) == (1, 2.5, (4, 99.5, None))
     assert mpa(1, 2.5) == (1, 2.5, ())
diff --git a/ext/pybind11/tests/test_local_bindings.cpp b/ext/pybind11/tests/test_local_bindings.cpp
new file mode 100644
index 000000000..97c02dbeb
--- /dev/null
+++ b/ext/pybind11/tests/test_local_bindings.cpp
@@ -0,0 +1,101 @@
+/*
+    tests/test_local_bindings.cpp -- tests the py::module_local class feature which makes a class
+                                     binding local to the module in which it is defined.
+
+    Copyright (c) 2017 Jason Rhinelander <jason@imaginary.ca>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include "local_bindings.h"
+#include <pybind11/stl.h>
+#include <pybind11/stl_bind.h>
+#include <numeric>
+
+TEST_SUBMODULE(local_bindings, m) {
+    // test_load_external
+    m.def("load_external1", [](ExternalType1 &e) { return e.i; });
+    m.def("load_external2", [](ExternalType2 &e) { return e.i; });
+
+    // test_local_bindings
+    // Register a class with py::module_local:
+    bind_local<LocalType, -1>(m, "LocalType", py::module_local())
+        .def("get3", [](LocalType &t) { return t.i + 3; })
+        ;
+
+    m.def("local_value", [](LocalType &l) { return l.i; });
+
+    // test_nonlocal_failure
+    // The main pybind11 test module is loaded first, so this registration will succeed (the second
+    // one, in pybind11_cross_module_tests.cpp, is designed to fail):
+    bind_local<NonLocalType, 0>(m, "NonLocalType")
+        .def(py::init<int>())
+        .def("get", [](LocalType &i) { return i.i; })
+        ;
+
+    // test_duplicate_local
+    // py::module_local declarations should be visible across compilation units that get linked together;
+    // this tries to register a duplicate local.  It depends on a definition in test_class.cpp and
+    // should raise a runtime error from the duplicate definition attempt.  If test_class isn't
+    // available it *also* throws a runtime error (with "test_class not enabled" as value).
+    m.def("register_local_external", [m]() {
+        auto main = py::module::import("pybind11_tests");
+        if (py::hasattr(main, "class_")) {
+            bind_local<LocalExternal, 7>(m, "LocalExternal", py::module_local());
+        }
+        else throw std::runtime_error("test_class not enabled");
+    });
+
+    // test_stl_bind_local
+    // stl_bind.h binders defaults to py::module_local if the types are local or converting:
+    py::bind_vector<LocalVec>(m, "LocalVec");
+    py::bind_map<LocalMap>(m, "LocalMap");
+    // and global if the type (or one of the types, for the map) is global:
+    py::bind_vector<NonLocalVec>(m, "NonLocalVec");
+    py::bind_map<NonLocalMap>(m, "NonLocalMap");
+
+    // test_stl_bind_global
+    // They can, however, be overridden to global using `py::module_local(false)`:
+    bind_local<NonLocal2, 10>(m, "NonLocal2");
+    py::bind_vector<LocalVec2>(m, "LocalVec2", py::module_local());
+    py::bind_map<NonLocalMap2>(m, "NonLocalMap2", py::module_local(false));
+
+    // test_mixed_local_global
+    // We try this both with the global type registered first and vice versa (the order shouldn't
+    // matter).
+    m.def("register_mixed_global", [m]() {
+        bind_local<MixedGlobalLocal, 100>(m, "MixedGlobalLocal", py::module_local(false));
+    });
+    m.def("register_mixed_local", [m]() {
+        bind_local<MixedLocalGlobal, 1000>(m, "MixedLocalGlobal", py::module_local());
+    });
+    m.def("get_mixed_gl", [](int i) { return MixedGlobalLocal(i); });
+    m.def("get_mixed_lg", [](int i) { return MixedLocalGlobal(i); });
+
+    // test_internal_locals_differ
+    m.def("local_cpp_types_addr", []() { return (uintptr_t) &py::detail::registered_local_types_cpp(); });
+
+    // test_stl_caster_vs_stl_bind
+    m.def("load_vector_via_caster", [](std::vector<int> v) {
+        return std::accumulate(v.begin(), v.end(), 0);
+    });
+
+    // test_cross_module_calls
+    m.def("return_self", [](LocalVec *v) { return v; });
+    m.def("return_copy", [](const LocalVec &v) { return LocalVec(v); });
+
+    class Cat : public pets::Pet { public: Cat(std::string name) : Pet(name) {}; };
+    py::class_<pets::Pet>(m, "Pet", py::module_local())
+        .def("get_name", &pets::Pet::name);
+    // Binding for local extending class:
+    py::class_<Cat, pets::Pet>(m, "Cat")
+        .def(py::init<std::string>());
+    m.def("pet_name", [](pets::Pet &p) { return p.name(); });
+
+    py::class_<MixGL>(m, "MixGL").def(py::init<int>());
+    m.def("get_gl_value", [](MixGL &o) { return o.i + 10; });
+
+    py::class_<MixGL2>(m, "MixGL2").def(py::init<int>());
+}
diff --git a/ext/pybind11/tests/test_local_bindings.py b/ext/pybind11/tests/test_local_bindings.py
new file mode 100644
index 000000000..b3dc3619c
--- /dev/null
+++ b/ext/pybind11/tests/test_local_bindings.py
@@ -0,0 +1,226 @@
+import pytest
+
+from pybind11_tests import local_bindings as m
+
+
+def test_load_external():
+    """Load a `py::module_local` type that's only registered in an external module"""
+    import pybind11_cross_module_tests as cm
+
+    assert m.load_external1(cm.ExternalType1(11)) == 11
+    assert m.load_external2(cm.ExternalType2(22)) == 22
+
+    with pytest.raises(TypeError) as excinfo:
+        assert m.load_external2(cm.ExternalType1(21)) == 21
+    assert "incompatible function arguments" in str(excinfo.value)
+
+    with pytest.raises(TypeError) as excinfo:
+        assert m.load_external1(cm.ExternalType2(12)) == 12
+    assert "incompatible function arguments" in str(excinfo.value)
+
+
+def test_local_bindings():
+    """Tests that duplicate `py::module_local` class bindings work across modules"""
+
+    # Make sure we can load the second module with the conflicting (but local) definition:
+    import pybind11_cross_module_tests as cm
+
+    i1 = m.LocalType(5)
+    assert i1.get() == 4
+    assert i1.get3() == 8
+
+    i2 = cm.LocalType(10)
+    assert i2.get() == 11
+    assert i2.get2() == 12
+
+    assert not hasattr(i1, 'get2')
+    assert not hasattr(i2, 'get3')
+
+    # Loading within the local module
+    assert m.local_value(i1) == 5
+    assert cm.local_value(i2) == 10
+
+    # Cross-module loading works as well (on failure, the type loader looks for
+    # external module-local converters):
+    assert m.local_value(i2) == 10
+    assert cm.local_value(i1) == 5
+
+
+def test_nonlocal_failure():
+    """Tests that attempting to register a non-local type in multiple modules fails"""
+    import pybind11_cross_module_tests as cm
+
+    with pytest.raises(RuntimeError) as excinfo:
+        cm.register_nonlocal()
+    assert str(excinfo.value) == 'generic_type: type "NonLocalType" is already registered!'
+
+
+def test_duplicate_local():
+    """Tests expected failure when registering a class twice with py::local in the same module"""
+    with pytest.raises(RuntimeError) as excinfo:
+        m.register_local_external()
+    import pybind11_tests
+    assert str(excinfo.value) == (
+        'generic_type: type "LocalExternal" is already registered!'
+        if hasattr(pybind11_tests, 'class_') else 'test_class not enabled')
+
+
+def test_stl_bind_local():
+    import pybind11_cross_module_tests as cm
+
+    v1, v2 = m.LocalVec(), cm.LocalVec()
+    v1.append(m.LocalType(1))
+    v1.append(m.LocalType(2))
+    v2.append(cm.LocalType(1))
+    v2.append(cm.LocalType(2))
+
+    # Cross module value loading:
+    v1.append(cm.LocalType(3))
+    v2.append(m.LocalType(3))
+
+    assert [i.get() for i in v1] == [0, 1, 2]
+    assert [i.get() for i in v2] == [2, 3, 4]
+
+    v3, v4 = m.NonLocalVec(), cm.NonLocalVec2()
+    v3.append(m.NonLocalType(1))
+    v3.append(m.NonLocalType(2))
+    v4.append(m.NonLocal2(3))
+    v4.append(m.NonLocal2(4))
+
+    assert [i.get() for i in v3] == [1, 2]
+    assert [i.get() for i in v4] == [13, 14]
+
+    d1, d2 = m.LocalMap(), cm.LocalMap()
+    d1["a"] = v1[0]
+    d1["b"] = v1[1]
+    d2["c"] = v2[0]
+    d2["d"] = v2[1]
+    assert {i: d1[i].get() for i in d1} == {'a': 0, 'b': 1}
+    assert {i: d2[i].get() for i in d2} == {'c': 2, 'd': 3}
+
+
+def test_stl_bind_global():
+    import pybind11_cross_module_tests as cm
+
+    with pytest.raises(RuntimeError) as excinfo:
+        cm.register_nonlocal_map()
+    assert str(excinfo.value) == 'generic_type: type "NonLocalMap" is already registered!'
+
+    with pytest.raises(RuntimeError) as excinfo:
+        cm.register_nonlocal_vec()
+    assert str(excinfo.value) == 'generic_type: type "NonLocalVec" is already registered!'
+
+    with pytest.raises(RuntimeError) as excinfo:
+        cm.register_nonlocal_map2()
+    assert str(excinfo.value) == 'generic_type: type "NonLocalMap2" is already registered!'
+
+
+def test_mixed_local_global():
+    """Local types take precedence over globally registered types: a module with a `module_local`
+    type can be registered even if the type is already registered globally.  With the module,
+    casting will go to the local type; outside the module casting goes to the global type."""
+    import pybind11_cross_module_tests as cm
+    m.register_mixed_global()
+    m.register_mixed_local()
+
+    a = []
+    a.append(m.MixedGlobalLocal(1))
+    a.append(m.MixedLocalGlobal(2))
+    a.append(m.get_mixed_gl(3))
+    a.append(m.get_mixed_lg(4))
+
+    assert [x.get() for x in a] == [101, 1002, 103, 1004]
+
+    cm.register_mixed_global_local()
+    cm.register_mixed_local_global()
+    a.append(m.MixedGlobalLocal(5))
+    a.append(m.MixedLocalGlobal(6))
+    a.append(cm.MixedGlobalLocal(7))
+    a.append(cm.MixedLocalGlobal(8))
+    a.append(m.get_mixed_gl(9))
+    a.append(m.get_mixed_lg(10))
+    a.append(cm.get_mixed_gl(11))
+    a.append(cm.get_mixed_lg(12))
+
+    assert [x.get() for x in a] == \
+        [101, 1002, 103, 1004, 105, 1006, 207, 2008, 109, 1010, 211, 2012]
+
+
+def test_internal_locals_differ():
+    """Makes sure the internal local type map differs across the two modules"""
+    import pybind11_cross_module_tests as cm
+    assert m.local_cpp_types_addr() != cm.local_cpp_types_addr()
+
+
+def test_stl_caster_vs_stl_bind(msg):
+    """One module uses a generic vector caster from `<pybind11/stl.h>` while the other
+    exports `std::vector<int>` via `py:bind_vector` and `py::module_local`"""
+    import pybind11_cross_module_tests as cm
+
+    v1 = cm.VectorInt([1, 2, 3])
+    assert m.load_vector_via_caster(v1) == 6
+    assert cm.load_vector_via_binding(v1) == 6
+
+    v2 = [1, 2, 3]
+    assert m.load_vector_via_caster(v2) == 6
+    with pytest.raises(TypeError) as excinfo:
+        cm.load_vector_via_binding(v2) == 6
+    assert msg(excinfo.value) == """
+    load_vector_via_binding(): incompatible function arguments. The following argument types are supported:
+        1. (arg0: pybind11_cross_module_tests.VectorInt) -> int
+
+    Invoked with: [1, 2, 3]
+    """  # noqa: E501 line too long
+
+
+def test_cross_module_calls():
+    import pybind11_cross_module_tests as cm
+
+    v1 = m.LocalVec()
+    v1.append(m.LocalType(1))
+    v2 = cm.LocalVec()
+    v2.append(cm.LocalType(2))
+
+    # Returning the self pointer should get picked up as returning an existing
+    # instance (even when that instance is of a foreign, non-local type).
+    assert m.return_self(v1) is v1
+    assert cm.return_self(v2) is v2
+    assert m.return_self(v2) is v2
+    assert cm.return_self(v1) is v1
+
+    assert m.LocalVec is not cm.LocalVec
+    # Returning a copy, on the other hand, always goes to the local type,
+    # regardless of where the source type came from.
+    assert type(m.return_copy(v1)) is m.LocalVec
+    assert type(m.return_copy(v2)) is m.LocalVec
+    assert type(cm.return_copy(v1)) is cm.LocalVec
+    assert type(cm.return_copy(v2)) is cm.LocalVec
+
+    # Test the example given in the documentation (which also tests inheritance casting):
+    mycat = m.Cat("Fluffy")
+    mydog = cm.Dog("Rover")
+    assert mycat.get_name() == "Fluffy"
+    assert mydog.name() == "Rover"
+    assert m.Cat.__base__.__name__ == "Pet"
+    assert cm.Dog.__base__.__name__ == "Pet"
+    assert m.Cat.__base__ is not cm.Dog.__base__
+    assert m.pet_name(mycat) == "Fluffy"
+    assert m.pet_name(mydog) == "Rover"
+    assert cm.pet_name(mycat) == "Fluffy"
+    assert cm.pet_name(mydog) == "Rover"
+
+    assert m.MixGL is not cm.MixGL
+    a = m.MixGL(1)
+    b = cm.MixGL(2)
+    assert m.get_gl_value(a) == 11
+    assert m.get_gl_value(b) == 12
+    assert cm.get_gl_value(a) == 101
+    assert cm.get_gl_value(b) == 102
+
+    c, d = m.MixGL2(3), cm.MixGL2(4)
+    with pytest.raises(TypeError) as excinfo:
+        m.get_gl_value(c)
+    assert "incompatible function arguments" in str(excinfo)
+    with pytest.raises(TypeError) as excinfo:
+        m.get_gl_value(d)
+    assert "incompatible function arguments" in str(excinfo)
diff --git a/ext/pybind11/tests/test_methods_and_attributes.cpp b/ext/pybind11/tests/test_methods_and_attributes.cpp
index b7b2edfd8..cd15869f4 100644
--- a/ext/pybind11/tests/test_methods_and_attributes.cpp
+++ b/ext/pybind11/tests/test_methods_and_attributes.cpp
@@ -26,39 +26,44 @@ public:
     void operator=(const ExampleMandA &e) { print_copy_assigned(this); value = e.value; }
     void operator=(ExampleMandA &&e) { print_move_assigned(this); value = e.value; }
 
-    void add1(ExampleMandA other) { value += other.value; }           // passing by value
-    void add2(ExampleMandA &other) { value += other.value; }          // passing by reference
-    void add3(const ExampleMandA &other) { value += other.value; }    // passing by const reference
-    void add4(ExampleMandA *other) { value += other->value; }         // passing by pointer
-    void add5(const ExampleMandA *other) { value += other->value; }   // passing by const pointer
-
-    void add6(int other) { value += other; }                      // passing by value
-    void add7(int &other) { value += other; }                     // passing by reference
-    void add8(const int &other) { value += other; }               // passing by const reference
-    void add9(int *other) { value += *other; }                    // passing by pointer
-    void add10(const int *other) { value += *other; }             // passing by const pointer
-
-    ExampleMandA self1() { return *this; }                            // return by value
-    ExampleMandA &self2() { return *this; }                           // return by reference
-    const ExampleMandA &self3() { return *this; }                     // return by const reference
-    ExampleMandA *self4() { return this; }                            // return by pointer
-    const ExampleMandA *self5() { return this; }                      // return by const pointer
-
-    int internal1() { return value; }                             // return by value
-    int &internal2() { return value; }                            // return by reference
-    const int &internal3() { return value; }                      // return by const reference
-    int *internal4() { return &value; }                           // return by pointer
-    const int *internal5() { return &value; }                     // return by const pointer
-
+    void add1(ExampleMandA other) { value += other.value; }         // passing by value
+    void add2(ExampleMandA &other) { value += other.value; }        // passing by reference
+    void add3(const ExampleMandA &other) { value += other.value; }  // passing by const reference
+    void add4(ExampleMandA *other) { value += other->value; }       // passing by pointer
+    void add5(const ExampleMandA *other) { value += other->value; } // passing by const pointer
+
+    void add6(int other) { value += other; }                        // passing by value
+    void add7(int &other) { value += other; }                       // passing by reference
+    void add8(const int &other) { value += other; }                 // passing by const reference
+    void add9(int *other) { value += *other; }                      // passing by pointer
+    void add10(const int *other) { value += *other; }               // passing by const pointer
+
+    ExampleMandA self1() { return *this; }                          // return by value
+    ExampleMandA &self2() { return *this; }                         // return by reference
+    const ExampleMandA &self3() { return *this; }                   // return by const reference
+    ExampleMandA *self4() { return this; }                          // return by pointer
+    const ExampleMandA *self5() { return this; }                    // return by const pointer
+
+    int internal1() { return value; }                               // return by value
+    int &internal2() { return value; }                              // return by reference
+    const int &internal3() { return value; }                        // return by const reference
+    int *internal4() { return &value; }                             // return by pointer
+    const int *internal5() { return &value; }                       // return by const pointer
+
+    py::str overloaded()             { return "()"; }
+    py::str overloaded(int)          { return "(int)"; }
     py::str overloaded(int, float)   { return "(int, float)"; }
     py::str overloaded(float, int)   { return "(float, int)"; }
     py::str overloaded(int, int)     { return "(int, int)"; }
     py::str overloaded(float, float) { return "(float, float)"; }
+    py::str overloaded(int)          const { return "(int) const"; }
     py::str overloaded(int, float)   const { return "(int, float) const"; }
     py::str overloaded(float, int)   const { return "(float, int) const"; }
     py::str overloaded(int, int)     const { return "(int, int) const"; }
     py::str overloaded(float, float) const { return "(float, float) const"; }
 
+    static py::str overloaded(float) { return "static float"; }
+
     int value = 0;
 };
 
@@ -72,34 +77,28 @@ struct TestProperties {
     static int static_get() { return static_value; }
     static void static_set(int v) { static_value = v; }
 };
-
 int TestProperties::static_value = 1;
 
-struct SimpleValue { int value = 1; };
-
-struct TestPropRVP {
-    SimpleValue v1;
-    SimpleValue v2;
-    static SimpleValue sv1;
-    static SimpleValue sv2;
-
-    const SimpleValue &get1() const { return v1; }
-    const SimpleValue &get2() const { return v2; }
-    SimpleValue get_rvalue() const { return v2; }
-    void set1(int v) { v1.value = v; }
-    void set2(int v) { v2.value = v; }
+struct TestPropertiesOverride : TestProperties {
+    int value = 99;
+    static int static_value;
 };
+int TestPropertiesOverride::static_value = 99;
 
-SimpleValue TestPropRVP::sv1{};
-SimpleValue TestPropRVP::sv2{};
-
-class DynamicClass {
-public:
-    DynamicClass() { print_default_created(this); }
-    ~DynamicClass() { print_destroyed(this); }
+struct TestPropRVP {
+    UserType v1{1};
+    UserType v2{1};
+    static UserType sv1;
+    static UserType sv2;
+
+    const UserType &get1() const { return v1; }
+    const UserType &get2() const { return v2; }
+    UserType get_rvalue() const { return v2; }
+    void set1(int v) { v1.set(v); }
+    void set2(int v) { v2.set(v); }
 };
-
-class CppDerivedDynamicClass : public DynamicClass { };
+UserType TestPropRVP::sv1(1);
+UserType TestPropRVP::sv2(1);
 
 // py::arg/py::arg_v testing: these arguments just record their argument when invoked
 class ArgInspector1 { public: std::string arg = "(default arg inspector 1)"; };
@@ -145,17 +144,68 @@ public:
     }
 
     static handle cast(const ArgAlwaysConverts &, return_value_policy, handle) {
-        return py::none();
+        return py::none().release();
     }
 };
 }}
 
-/// Issue/PR #648: bad arg default debugging output
-class NotRegistered {};
+// test_custom_caster_destruction
+class DestructionTester {
+public:
+    DestructionTester() { print_default_created(this); }
+    ~DestructionTester() { print_destroyed(this); }
+    DestructionTester(const DestructionTester &) { print_copy_created(this); }
+    DestructionTester(DestructionTester &&) { print_move_created(this); }
+    DestructionTester &operator=(const DestructionTester &) { print_copy_assigned(this); return *this; }
+    DestructionTester &operator=(DestructionTester &&) { print_move_assigned(this); return *this; }
+};
+namespace pybind11 { namespace detail {
+template <> struct type_caster<DestructionTester> {
+    PYBIND11_TYPE_CASTER(DestructionTester, _("DestructionTester"));
+    bool load(handle, bool) { return true; }
 
-test_initializer methods_and_attributes([](py::module &m) {
-    py::class_<ExampleMandA>(m, "ExampleMandA")
-        .def(py::init<>())
+    static handle cast(const DestructionTester &, return_value_policy, handle) {
+        return py::bool_(true).release();
+    }
+};
+}}
+
+// Test None-allowed py::arg argument policy
+class NoneTester { public: int answer = 42; };
+int none1(const NoneTester &obj) { return obj.answer; }
+int none2(NoneTester *obj) { return obj ? obj->answer : -1; }
+int none3(std::shared_ptr<NoneTester> &obj) { return obj ? obj->answer : -1; }
+int none4(std::shared_ptr<NoneTester> *obj) { return obj && *obj ? (*obj)->answer : -1; }
+int none5(std::shared_ptr<NoneTester> obj) { return obj ? obj->answer : -1; }
+
+struct StrIssue {
+    int val = -1;
+
+    StrIssue() = default;
+    StrIssue(int i) : val{i} {}
+};
+
+// Issues #854, #910: incompatible function args when member function/pointer is in unregistered base class
+class UnregisteredBase {
+public:
+    void do_nothing() const {}
+    void increase_value() { rw_value++; ro_value += 0.25; }
+    void set_int(int v) { rw_value = v; }
+    int get_int() const { return rw_value; }
+    double get_double() const { return ro_value; }
+    int rw_value = 42;
+    double ro_value = 1.25;
+};
+class RegisteredDerived : public UnregisteredBase {
+public:
+    using UnregisteredBase::UnregisteredBase;
+    double sum() const { return rw_value + ro_value; }
+};
+
+TEST_SUBMODULE(methods_and_attributes, m) {
+    // test_methods_and_attributes
+    py::class_<ExampleMandA> emna(m, "ExampleMandA");
+    emna.def(py::init<>())
         .def(py::init<int>())
         .def(py::init<const ExampleMandA&>())
         .def("add1", &ExampleMandA::add1)
@@ -179,29 +229,52 @@ test_initializer methods_and_attributes([](py::module &m) {
         .def("internal4", &ExampleMandA::internal4)
         .def("internal5", &ExampleMandA::internal5)
 #if defined(PYBIND11_OVERLOAD_CAST)
+        .def("overloaded", py::overload_cast<>(&ExampleMandA::overloaded))
+        .def("overloaded", py::overload_cast<int>(&ExampleMandA::overloaded))
         .def("overloaded", py::overload_cast<int,   float>(&ExampleMandA::overloaded))
         .def("overloaded", py::overload_cast<float,   int>(&ExampleMandA::overloaded))
         .def("overloaded", py::overload_cast<int,     int>(&ExampleMandA::overloaded))
         .def("overloaded", py::overload_cast<float, float>(&ExampleMandA::overloaded))
         .def("overloaded_float", py::overload_cast<float, float>(&ExampleMandA::overloaded))
+        .def("overloaded_const", py::overload_cast<int         >(&ExampleMandA::overloaded, py::const_))
         .def("overloaded_const", py::overload_cast<int,   float>(&ExampleMandA::overloaded, py::const_))
         .def("overloaded_const", py::overload_cast<float,   int>(&ExampleMandA::overloaded, py::const_))
         .def("overloaded_const", py::overload_cast<int,     int>(&ExampleMandA::overloaded, py::const_))
         .def("overloaded_const", py::overload_cast<float, float>(&ExampleMandA::overloaded, py::const_))
 #else
+        .def("overloaded", static_cast<py::str (ExampleMandA::*)()>(&ExampleMandA::overloaded))
+        .def("overloaded", static_cast<py::str (ExampleMandA::*)(int)>(&ExampleMandA::overloaded))
         .def("overloaded", static_cast<py::str (ExampleMandA::*)(int,   float)>(&ExampleMandA::overloaded))
         .def("overloaded", static_cast<py::str (ExampleMandA::*)(float,   int)>(&ExampleMandA::overloaded))
         .def("overloaded", static_cast<py::str (ExampleMandA::*)(int,     int)>(&ExampleMandA::overloaded))
         .def("overloaded", static_cast<py::str (ExampleMandA::*)(float, float)>(&ExampleMandA::overloaded))
         .def("overloaded_float", static_cast<py::str (ExampleMandA::*)(float, float)>(&ExampleMandA::overloaded))
+        .def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int         ) const>(&ExampleMandA::overloaded))
         .def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int,   float) const>(&ExampleMandA::overloaded))
         .def("overloaded_const", static_cast<py::str (ExampleMandA::*)(float,   int) const>(&ExampleMandA::overloaded))
         .def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int,     int) const>(&ExampleMandA::overloaded))
         .def("overloaded_const", static_cast<py::str (ExampleMandA::*)(float, float) const>(&ExampleMandA::overloaded))
 #endif
+        // test_no_mixed_overloads
+        // Raise error if trying to mix static/non-static overloads on the same name:
+        .def_static("add_mixed_overloads1", []() {
+            auto emna = py::reinterpret_borrow<py::class_<ExampleMandA>>(py::module::import("pybind11_tests.methods_and_attributes").attr("ExampleMandA"));
+            emna.def       ("overload_mixed1", static_cast<py::str (ExampleMandA::*)(int, int)>(&ExampleMandA::overloaded))
+                .def_static("overload_mixed1", static_cast<py::str (              *)(float   )>(&ExampleMandA::overloaded));
+        })
+        .def_static("add_mixed_overloads2", []() {
+            auto emna = py::reinterpret_borrow<py::class_<ExampleMandA>>(py::module::import("pybind11_tests.methods_and_attributes").attr("ExampleMandA"));
+            emna.def_static("overload_mixed2", static_cast<py::str (              *)(float   )>(&ExampleMandA::overloaded))
+                .def       ("overload_mixed2", static_cast<py::str (ExampleMandA::*)(int, int)>(&ExampleMandA::overloaded));
+        })
         .def("__str__", &ExampleMandA::toString)
         .def_readwrite("value", &ExampleMandA::value);
 
+    // test_copy_method
+    // Issue #443: can't call copied methods in Python 3
+    emna.attr("add2b") = emna.attr("add2");
+
+    // test_properties, test_static_properties, test_static_cls
     py::class_<TestProperties>(m, "TestProperties")
         .def(py::init<>())
         .def_readonly("def_readonly", &TestProperties::value)
@@ -219,15 +292,18 @@ test_initializer methods_and_attributes([](py::module &m) {
                              [](py::object cls) { return cls; },
                              [](py::object cls, py::function f) { f(cls); });
 
-    py::class_<SimpleValue>(m, "SimpleValue")
-        .def_readwrite("value", &SimpleValue::value);
+    py::class_<TestPropertiesOverride, TestProperties>(m, "TestPropertiesOverride")
+        .def(py::init<>())
+        .def_readonly("def_readonly", &TestPropertiesOverride::value)
+        .def_readonly_static("def_readonly_static", &TestPropertiesOverride::static_value);
 
-    auto static_get1 = [](py::object) -> const SimpleValue & { return TestPropRVP::sv1; };
-    auto static_get2 = [](py::object) -> const SimpleValue & { return TestPropRVP::sv2; };
-    auto static_set1 = [](py::object, int v) { TestPropRVP::sv1.value = v; };
-    auto static_set2 = [](py::object, int v) { TestPropRVP::sv2.value = v; };
+    auto static_get1 = [](py::object) -> const UserType & { return TestPropRVP::sv1; };
+    auto static_get2 = [](py::object) -> const UserType & { return TestPropRVP::sv2; };
+    auto static_set1 = [](py::object, int v) { TestPropRVP::sv1.set(v); };
+    auto static_set2 = [](py::object, int v) { TestPropRVP::sv2.set(v); };
     auto rvp_copy = py::return_value_policy::copy;
 
+    // test_property_return_value_policies
     py::class_<TestPropRVP>(m, "TestPropRVP")
         .def(py::init<>())
         .def_property_readonly("ro_ref", &TestPropRVP::get1)
@@ -242,21 +318,32 @@ test_initializer methods_and_attributes([](py::module &m) {
         .def_property_static("static_rw_ref", static_get1, static_set1)
         .def_property_static("static_rw_copy", static_get2, static_set2, rvp_copy)
         .def_property_static("static_rw_func", py::cpp_function(static_get2, rvp_copy), static_set2)
+        // test_property_rvalue_policy
         .def_property_readonly("rvalue", &TestPropRVP::get_rvalue)
-        .def_property_readonly_static("static_rvalue", [](py::object) { return SimpleValue(); });
+        .def_property_readonly_static("static_rvalue", [](py::object) { return UserType(1); });
 
+    // test_metaclass_override
     struct MetaclassOverride { };
     py::class_<MetaclassOverride>(m, "MetaclassOverride", py::metaclass((PyObject *) &PyType_Type))
         .def_property_readonly_static("readonly", [](py::object) { return 1; });
 
 #if !defined(PYPY_VERSION)
+    // test_dynamic_attributes
+    class DynamicClass {
+    public:
+        DynamicClass() { print_default_created(this); }
+        ~DynamicClass() { print_destroyed(this); }
+    };
     py::class_<DynamicClass>(m, "DynamicClass", py::dynamic_attr())
         .def(py::init());
 
+    class CppDerivedDynamicClass : public DynamicClass { };
     py::class_<CppDerivedDynamicClass, DynamicClass>(m, "CppDerivedDynamicClass")
         .def(py::init());
 #endif
 
+    // test_noconvert_args
+    //
     // Test converting.  The ArgAlwaysConverts is just there to make the first no-conversion pass
     // fail so that our call always ends up happening via the second dispatch (the one that allows
     // some conversion).
@@ -279,19 +366,81 @@ test_initializer methods_and_attributes([](py::module &m) {
 
     m.def("floats_preferred", [](double f) { return 0.5 * f; }, py::arg("f"));
     m.def("floats_only", [](double f) { return 0.5 * f; }, py::arg("f").noconvert());
+    m.def("ints_preferred", [](int i) { return i / 2; }, py::arg("i"));
+    m.def("ints_only", [](int i) { return i / 2; }, py::arg("i").noconvert());
 
-    /// Issue/PR #648: bad arg default debugging output
+    // test_bad_arg_default
+    // Issue/PR #648: bad arg default debugging output
 #if !defined(NDEBUG)
     m.attr("debug_enabled") = true;
 #else
     m.attr("debug_enabled") = false;
 #endif
     m.def("bad_arg_def_named", []{
-        auto m = py::module::import("pybind11_tests.issues");
-        m.def("should_fail", [](int, NotRegistered) {}, py::arg(), py::arg("a") = NotRegistered());
+        auto m = py::module::import("pybind11_tests");
+        m.def("should_fail", [](int, UnregisteredType) {}, py::arg(), py::arg("a") = UnregisteredType());
     });
     m.def("bad_arg_def_unnamed", []{
-        auto m = py::module::import("pybind11_tests.issues");
-        m.def("should_fail", [](int, NotRegistered) {}, py::arg(), py::arg() = NotRegistered());
+        auto m = py::module::import("pybind11_tests");
+        m.def("should_fail", [](int, UnregisteredType) {}, py::arg(), py::arg() = UnregisteredType());
     });
-});
+
+    // test_accepts_none
+    py::class_<NoneTester, std::shared_ptr<NoneTester>>(m, "NoneTester")
+        .def(py::init<>());
+    m.def("no_none1", &none1, py::arg().none(false));
+    m.def("no_none2", &none2, py::arg().none(false));
+    m.def("no_none3", &none3, py::arg().none(false));
+    m.def("no_none4", &none4, py::arg().none(false));
+    m.def("no_none5", &none5, py::arg().none(false));
+    m.def("ok_none1", &none1);
+    m.def("ok_none2", &none2, py::arg().none(true));
+    m.def("ok_none3", &none3);
+    m.def("ok_none4", &none4, py::arg().none(true));
+    m.def("ok_none5", &none5);
+
+    // test_str_issue
+    // Issue #283: __str__ called on uninitialized instance when constructor arguments invalid
+    py::class_<StrIssue>(m, "StrIssue")
+        .def(py::init<int>())
+        .def(py::init<>())
+        .def("__str__", [](const StrIssue &si) {
+            return "StrIssue[" + std::to_string(si.val) + "]"; }
+        );
+
+    // test_unregistered_base_implementations
+    //
+    // Issues #854/910: incompatible function args when member function/pointer is in unregistered
+    // base class The methods and member pointers below actually resolve to members/pointers in
+    // UnregisteredBase; before this test/fix they would be registered via lambda with a first
+    // argument of an unregistered type, and thus uncallable.
+    py::class_<RegisteredDerived>(m, "RegisteredDerived")
+        .def(py::init<>())
+        .def("do_nothing", &RegisteredDerived::do_nothing)
+        .def("increase_value", &RegisteredDerived::increase_value)
+        .def_readwrite("rw_value", &RegisteredDerived::rw_value)
+        .def_readonly("ro_value", &RegisteredDerived::ro_value)
+        // These should trigger a static_assert if uncommented
+        //.def_readwrite("fails", &UserType::value) // should trigger a static_assert if uncommented
+        //.def_readonly("fails", &UserType::value) // should trigger a static_assert if uncommented
+        .def_property("rw_value_prop", &RegisteredDerived::get_int, &RegisteredDerived::set_int)
+        .def_property_readonly("ro_value_prop", &RegisteredDerived::get_double)
+        // This one is in the registered class:
+        .def("sum", &RegisteredDerived::sum)
+        ;
+
+    using Adapted = decltype(py::method_adaptor<RegisteredDerived>(&RegisteredDerived::do_nothing));
+    static_assert(std::is_same<Adapted, void (RegisteredDerived::*)() const>::value, "");
+
+    // test_custom_caster_destruction
+    // Test that `take_ownership` works on types with a custom type caster when given a pointer
+
+    // default policy: don't take ownership:
+    m.def("custom_caster_no_destroy", []() { static auto *dt = new DestructionTester(); return dt; });
+
+    m.def("custom_caster_destroy", []() { return new DestructionTester(); },
+            py::return_value_policy::take_ownership); // Takes ownership: destroy when finished
+    m.def("custom_caster_destroy_const", []() -> const DestructionTester * { return new DestructionTester(); },
+            py::return_value_policy::take_ownership); // Likewise (const doesn't inhibit destruction)
+    m.def("destruction_tester_cstats", &ConstructorStats::get<DestructionTester>, py::return_value_policy::reference);
+}
diff --git a/ext/pybind11/tests/test_methods_and_attributes.py b/ext/pybind11/tests/test_methods_and_attributes.py
index f185ac26d..9fd9cb75c 100644
--- a/ext/pybind11/tests/test_methods_and_attributes.py
+++ b/ext/pybind11/tests/test_methods_and_attributes.py
@@ -1,10 +1,11 @@
 import pytest
-from pybind11_tests import ExampleMandA, ConstructorStats
+from pybind11_tests import methods_and_attributes as m
+from pybind11_tests import ConstructorStats
 
 
 def test_methods_and_attributes():
-    instance1 = ExampleMandA()
-    instance2 = ExampleMandA(32)
+    instance1 = m.ExampleMandA()
+    instance2 = m.ExampleMandA(32)
 
     instance1.add1(instance2)
     instance1.add2(instance2)
@@ -31,10 +32,13 @@ def test_methods_and_attributes():
     assert instance1.internal4() == 320
     assert instance1.internal5() == 320
 
+    assert instance1.overloaded() == "()"
+    assert instance1.overloaded(0) == "(int)"
     assert instance1.overloaded(1, 1.0) == "(int, float)"
     assert instance1.overloaded(2.0, 2) == "(float, int)"
     assert instance1.overloaded(3,   3) == "(int, int)"
     assert instance1.overloaded(4., 4.) == "(float, float)"
+    assert instance1.overloaded_const(-3) == "(int) const"
     assert instance1.overloaded_const(5, 5.0) == "(int, float) const"
     assert instance1.overloaded_const(6.0, 6) == "(float, int) const"
     assert instance1.overloaded_const(7,   7) == "(int, int) const"
@@ -48,7 +52,7 @@ def test_methods_and_attributes():
     instance1.value = 100
     assert str(instance1) == "ExampleMandA[value=100]"
 
-    cstats = ConstructorStats.get(ExampleMandA)
+    cstats = ConstructorStats.get(m.ExampleMandA)
     assert cstats.alive() == 2
     del instance1, instance2
     assert cstats.alive() == 0
@@ -60,10 +64,25 @@ def test_methods_and_attributes():
     assert cstats.move_assignments == 0
 
 
-def test_properties():
-    from pybind11_tests import TestProperties
+def test_copy_method():
+    """Issue #443: calling copied methods fails in Python 3"""
+
+    m.ExampleMandA.add2c = m.ExampleMandA.add2
+    m.ExampleMandA.add2d = m.ExampleMandA.add2b
+    a = m.ExampleMandA(123)
+    assert a.value == 123
+    a.add2(m.ExampleMandA(-100))
+    assert a.value == 23
+    a.add2b(m.ExampleMandA(20))
+    assert a.value == 43
+    a.add2c(m.ExampleMandA(6))
+    assert a.value == 49
+    a.add2d(m.ExampleMandA(-7))
+    assert a.value == 42
 
-    instance = TestProperties()
+
+def test_properties():
+    instance = m.TestProperties()
 
     assert instance.def_readonly == 1
     with pytest.raises(AttributeError):
@@ -81,75 +100,96 @@ def test_properties():
 
 
 def test_static_properties():
-    from pybind11_tests import TestProperties as Type
-
-    assert Type.def_readonly_static == 1
+    assert m.TestProperties.def_readonly_static == 1
     with pytest.raises(AttributeError) as excinfo:
-        Type.def_readonly_static = 2
+        m.TestProperties.def_readonly_static = 2
     assert "can't set attribute" in str(excinfo)
 
-    Type.def_readwrite_static = 2
-    assert Type.def_readwrite_static == 2
+    m.TestProperties.def_readwrite_static = 2
+    assert m.TestProperties.def_readwrite_static == 2
 
-    assert Type.def_property_readonly_static == 2
+    assert m.TestProperties.def_property_readonly_static == 2
     with pytest.raises(AttributeError) as excinfo:
-        Type.def_property_readonly_static = 3
+        m.TestProperties.def_property_readonly_static = 3
     assert "can't set attribute" in str(excinfo)
 
-    Type.def_property_static = 3
-    assert Type.def_property_static == 3
+    m.TestProperties.def_property_static = 3
+    assert m.TestProperties.def_property_static == 3
 
     # Static property read and write via instance
-    instance = Type()
+    instance = m.TestProperties()
 
-    Type.def_readwrite_static = 0
-    assert Type.def_readwrite_static == 0
+    m.TestProperties.def_readwrite_static = 0
+    assert m.TestProperties.def_readwrite_static == 0
     assert instance.def_readwrite_static == 0
 
     instance.def_readwrite_static = 2
-    assert Type.def_readwrite_static == 2
+    assert m.TestProperties.def_readwrite_static == 2
     assert instance.def_readwrite_static == 2
 
+    # It should be possible to override properties in derived classes
+    assert m.TestPropertiesOverride().def_readonly == 99
+    assert m.TestPropertiesOverride.def_readonly_static == 99
+
 
 def test_static_cls():
     """Static property getter and setters expect the type object as the their only argument"""
-    from pybind11_tests import TestProperties as Type
 
-    instance = Type()
-    assert Type.static_cls is Type
-    assert instance.static_cls is Type
+    instance = m.TestProperties()
+    assert m.TestProperties.static_cls is m.TestProperties
+    assert instance.static_cls is m.TestProperties
 
     def check_self(self):
-        assert self is Type
+        assert self is m.TestProperties
 
-    Type.static_cls = check_self
+    m.TestProperties.static_cls = check_self
     instance.static_cls = check_self
 
 
 def test_metaclass_override():
     """Overriding pybind11's default metaclass changes the behavior of `static_property`"""
-    from pybind11_tests import MetaclassOverride
 
-    assert type(ExampleMandA).__name__ == "pybind11_type"
-    assert type(MetaclassOverride).__name__ == "type"
+    assert type(m.ExampleMandA).__name__ == "pybind11_type"
+    assert type(m.MetaclassOverride).__name__ == "type"
 
-    assert MetaclassOverride.readonly == 1
-    assert type(MetaclassOverride.__dict__["readonly"]).__name__ == "pybind11_static_property"
+    assert m.MetaclassOverride.readonly == 1
+    assert type(m.MetaclassOverride.__dict__["readonly"]).__name__ == "pybind11_static_property"
 
     # Regular `type` replaces the property instead of calling `__set__()`
-    MetaclassOverride.readonly = 2
-    assert MetaclassOverride.readonly == 2
-    assert isinstance(MetaclassOverride.__dict__["readonly"], int)
+    m.MetaclassOverride.readonly = 2
+    assert m.MetaclassOverride.readonly == 2
+    assert isinstance(m.MetaclassOverride.__dict__["readonly"], int)
+
+
+def test_no_mixed_overloads():
+    from pybind11_tests import debug_enabled
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.ExampleMandA.add_mixed_overloads1()
+    assert (str(excinfo.value) ==
+            "overloading a method with both static and instance methods is not supported; " +
+            ("compile in debug mode for more details" if not debug_enabled else
+             "error while attempting to bind static method ExampleMandA.overload_mixed1"
+             "(arg0: float) -> str")
+            )
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.ExampleMandA.add_mixed_overloads2()
+    assert (str(excinfo.value) ==
+            "overloading a method with both static and instance methods is not supported; " +
+            ("compile in debug mode for more details" if not debug_enabled else
+             "error while attempting to bind instance method ExampleMandA.overload_mixed2"
+             "(self: pybind11_tests.methods_and_attributes.ExampleMandA, arg0: int, arg1: int)"
+             " -> str")
+            )
 
 
 @pytest.mark.parametrize("access", ["ro", "rw", "static_ro", "static_rw"])
 def test_property_return_value_policies(access):
-    from pybind11_tests import TestPropRVP
-
     if not access.startswith("static"):
-        obj = TestPropRVP()
+        obj = m.TestPropRVP()
     else:
-        obj = TestPropRVP
+        obj = m.TestPropRVP
 
     ref = getattr(obj, access + "_ref")
     assert ref.value == 1
@@ -170,30 +210,20 @@ def test_property_return_value_policies(access):
 
 def test_property_rvalue_policy():
     """When returning an rvalue, the return value policy is automatically changed from
-    `reference(_internal)` to `move`. The following would not work otherwise.
-    """
-    from pybind11_tests import TestPropRVP
+    `reference(_internal)` to `move`. The following would not work otherwise."""
 
-    instance = TestPropRVP()
+    instance = m.TestPropRVP()
     o = instance.rvalue
     assert o.value == 1
 
-
-def test_property_rvalue_policy_static():
-    """When returning an rvalue, the return value policy is automatically changed from
-    `reference(_internal)` to `move`. The following would not work otherwise.
-    """
-    from pybind11_tests import TestPropRVP
-    o = TestPropRVP.static_rvalue
-    assert o.value == 1
+    os = m.TestPropRVP.static_rvalue
+    assert os.value == 1
 
 
 # https://bitbucket.org/pypy/pypy/issues/2447
 @pytest.unsupported_on_pypy
 def test_dynamic_attributes():
-    from pybind11_tests import DynamicClass, CppDerivedDynamicClass
-
-    instance = DynamicClass()
+    instance = m.DynamicClass()
     assert not hasattr(instance, "foo")
     assert "foo" not in dir(instance)
 
@@ -213,16 +243,16 @@ def test_dynamic_attributes():
         instance.__dict__ = []
     assert str(excinfo.value) == "__dict__ must be set to a dictionary, not a 'list'"
 
-    cstats = ConstructorStats.get(DynamicClass)
+    cstats = ConstructorStats.get(m.DynamicClass)
     assert cstats.alive() == 1
     del instance
     assert cstats.alive() == 0
 
     # Derived classes should work as well
-    class PythonDerivedDynamicClass(DynamicClass):
+    class PythonDerivedDynamicClass(m.DynamicClass):
         pass
 
-    for cls in CppDerivedDynamicClass, PythonDerivedDynamicClass:
+    for cls in m.CppDerivedDynamicClass, PythonDerivedDynamicClass:
         derived = cls()
         derived.foobar = 100
         assert derived.foobar == 100
@@ -235,20 +265,18 @@ def test_dynamic_attributes():
 # https://bitbucket.org/pypy/pypy/issues/2447
 @pytest.unsupported_on_pypy
 def test_cyclic_gc():
-    from pybind11_tests import DynamicClass
-
     # One object references itself
-    instance = DynamicClass()
+    instance = m.DynamicClass()
     instance.circular_reference = instance
 
-    cstats = ConstructorStats.get(DynamicClass)
+    cstats = ConstructorStats.get(m.DynamicClass)
     assert cstats.alive() == 1
     del instance
     assert cstats.alive() == 0
 
     # Two object reference each other
-    i1 = DynamicClass()
-    i2 = DynamicClass()
+    i1 = m.DynamicClass()
+    i2 = m.DynamicClass()
     i1.cycle = i2
     i2.cycle = i1
 
@@ -258,9 +286,7 @@ def test_cyclic_gc():
 
 
 def test_noconvert_args(msg):
-    from pybind11_tests import ArgInspector, arg_inspect_func, floats_only, floats_preferred
-
-    a = ArgInspector()
+    a = m.ArgInspector()
     assert msg(a.f("hi")) == """
         loading ArgInspector1 argument WITH conversion allowed.  Argument value = hi
     """
@@ -284,15 +310,15 @@ def test_noconvert_args(msg):
     """
     assert (a.h("arg 1") ==
             "loading ArgInspector2 argument WITHOUT conversion allowed.  Argument value = arg 1")
-    assert msg(arg_inspect_func("A1", "A2")) == """
+    assert msg(m.arg_inspect_func("A1", "A2")) == """
         loading ArgInspector2 argument WITH conversion allowed.  Argument value = A1
         loading ArgInspector1 argument WITHOUT conversion allowed.  Argument value = A2
     """
 
-    assert floats_preferred(4) == 2.0
-    assert floats_only(4.0) == 2.0
+    assert m.floats_preferred(4) == 2.0
+    assert m.floats_only(4.0) == 2.0
     with pytest.raises(TypeError) as excinfo:
-        floats_only(4)
+        m.floats_only(4)
     assert msg(excinfo.value) == """
         floats_only(): incompatible function arguments. The following argument types are supported:
             1. (f: float) -> float
@@ -300,26 +326,151 @@ def test_noconvert_args(msg):
         Invoked with: 4
     """
 
+    assert m.ints_preferred(4) == 2
+    assert m.ints_preferred(True) == 0
+    with pytest.raises(TypeError) as excinfo:
+        m.ints_preferred(4.0)
+    assert msg(excinfo.value) == """
+        ints_preferred(): incompatible function arguments. The following argument types are supported:
+            1. (i: int) -> int
+
+        Invoked with: 4.0
+    """  # noqa: E501 line too long
+
+    assert m.ints_only(4) == 2
+    with pytest.raises(TypeError) as excinfo:
+        m.ints_only(4.0)
+    assert msg(excinfo.value) == """
+        ints_only(): incompatible function arguments. The following argument types are supported:
+            1. (i: int) -> int
+
+        Invoked with: 4.0
+    """
+
 
 def test_bad_arg_default(msg):
-    from pybind11_tests import debug_enabled, bad_arg_def_named, bad_arg_def_unnamed
+    from pybind11_tests import debug_enabled
 
     with pytest.raises(RuntimeError) as excinfo:
-        bad_arg_def_named()
+        m.bad_arg_def_named()
     assert msg(excinfo.value) == (
-        "arg(): could not convert default argument 'a: NotRegistered' in function 'should_fail' "
-        "into a Python object (type not registered yet?)"
+        "arg(): could not convert default argument 'a: UnregisteredType' in function "
+        "'should_fail' into a Python object (type not registered yet?)"
         if debug_enabled else
         "arg(): could not convert default argument into a Python object (type not registered "
         "yet?). Compile in debug mode for more information."
     )
 
     with pytest.raises(RuntimeError) as excinfo:
-        bad_arg_def_unnamed()
+        m.bad_arg_def_unnamed()
     assert msg(excinfo.value) == (
-        "arg(): could not convert default argument 'NotRegistered' in function 'should_fail' "
-        "into a Python object (type not registered yet?)"
+        "arg(): could not convert default argument 'UnregisteredType' in function "
+        "'should_fail' into a Python object (type not registered yet?)"
         if debug_enabled else
         "arg(): could not convert default argument into a Python object (type not registered "
         "yet?). Compile in debug mode for more information."
     )
+
+
+def test_accepts_none(msg):
+    a = m.NoneTester()
+    assert m.no_none1(a) == 42
+    assert m.no_none2(a) == 42
+    assert m.no_none3(a) == 42
+    assert m.no_none4(a) == 42
+    assert m.no_none5(a) == 42
+    assert m.ok_none1(a) == 42
+    assert m.ok_none2(a) == 42
+    assert m.ok_none3(a) == 42
+    assert m.ok_none4(a) == 42
+    assert m.ok_none5(a) == 42
+
+    with pytest.raises(TypeError) as excinfo:
+        m.no_none1(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.no_none2(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.no_none3(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.no_none4(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+    with pytest.raises(TypeError) as excinfo:
+        m.no_none5(None)
+    assert "incompatible function arguments" in str(excinfo.value)
+
+    # The first one still raises because you can't pass None as a lvalue reference arg:
+    with pytest.raises(TypeError) as excinfo:
+        assert m.ok_none1(None) == -1
+    assert msg(excinfo.value) == """
+        ok_none1(): incompatible function arguments. The following argument types are supported:
+            1. (arg0: m.methods_and_attributes.NoneTester) -> int
+
+        Invoked with: None
+    """
+
+    # The rest take the argument as pointer or holder, and accept None:
+    assert m.ok_none2(None) == -1
+    assert m.ok_none3(None) == -1
+    assert m.ok_none4(None) == -1
+    assert m.ok_none5(None) == -1
+
+
+def test_str_issue(msg):
+    """#283: __str__ called on uninitialized instance when constructor arguments invalid"""
+
+    assert str(m.StrIssue(3)) == "StrIssue[3]"
+
+    with pytest.raises(TypeError) as excinfo:
+        str(m.StrIssue("no", "such", "constructor"))
+    assert msg(excinfo.value) == """
+        __init__(): incompatible constructor arguments. The following argument types are supported:
+            1. m.methods_and_attributes.StrIssue(arg0: int)
+            2. m.methods_and_attributes.StrIssue()
+
+        Invoked with: 'no', 'such', 'constructor'
+    """
+
+
+def test_unregistered_base_implementations():
+    a = m.RegisteredDerived()
+    a.do_nothing()
+    assert a.rw_value == 42
+    assert a.ro_value == 1.25
+    a.rw_value += 5
+    assert a.sum() == 48.25
+    a.increase_value()
+    assert a.rw_value == 48
+    assert a.ro_value == 1.5
+    assert a.sum() == 49.5
+    assert a.rw_value_prop == 48
+    a.rw_value_prop += 1
+    assert a.rw_value_prop == 49
+    a.increase_value()
+    assert a.ro_value_prop == 1.75
+
+
+def test_custom_caster_destruction():
+    """Tests that returning a pointer to a type that gets converted with a custom type caster gets
+    destroyed when the function has py::return_value_policy::take_ownership policy applied."""
+
+    cstats = m.destruction_tester_cstats()
+    # This one *doesn't* have take_ownership: the pointer should be used but not destroyed:
+    z = m.custom_caster_no_destroy()
+    assert cstats.alive() == 1 and cstats.default_constructions == 1
+    assert z
+
+    # take_ownership applied: this constructs a new object, casts it, then destroys it:
+    z = m.custom_caster_destroy()
+    assert z
+    assert cstats.default_constructions == 2
+
+    # Same, but with a const pointer return (which should *not* inhibit destruction):
+    z = m.custom_caster_destroy_const()
+    assert z
+    assert cstats.default_constructions == 3
+
+    # Make sure we still only have the original object (from ..._no_destroy()) alive:
+    assert cstats.alive() == 1
diff --git a/ext/pybind11/tests/test_modules.cpp b/ext/pybind11/tests/test_modules.cpp
index 50c7d8412..c1475fa62 100644
--- a/ext/pybind11/tests/test_modules.cpp
+++ b/ext/pybind11/tests/test_modules.cpp
@@ -11,42 +11,38 @@
 #include "pybind11_tests.h"
 #include "constructor_stats.h"
 
-std::string submodule_func() {
-    return "submodule_func()";
-}
-
-class A {
-public:
-    A(int v) : v(v) { print_created(this, v); }
-    ~A() { print_destroyed(this); }
-    A(const A&) { print_copy_created(this); }
-    A& operator=(const A &copy) { print_copy_assigned(this); v = copy.v; return *this; }
-    std::string toString() { return "A[" + std::to_string(v) + "]"; }
-private:
-    int v;
-};
-
-class B {
-public:
-    B() { print_default_created(this); }
-    ~B() { print_destroyed(this); }
-    B(const B&) { print_copy_created(this); }
-    B& operator=(const B &copy) { print_copy_assigned(this); a1 = copy.a1; a2 = copy.a2; return *this; }
-    A &get_a1() { return a1; }
-    A &get_a2() { return a2; }
-
-    A a1{1};
-    A a2{2};
-};
-
-test_initializer modules([](py::module &m) {
-    py::module m_sub = m.def_submodule("submodule");
-    m_sub.def("submodule_func", &submodule_func);
+TEST_SUBMODULE(modules, m) {
+    // test_nested_modules
+    py::module m_sub = m.def_submodule("subsubmodule");
+    m_sub.def("submodule_func", []() { return "submodule_func()"; });
 
+    // test_reference_internal
+    class A {
+    public:
+        A(int v) : v(v) { print_created(this, v); }
+        ~A() { print_destroyed(this); }
+        A(const A&) { print_copy_created(this); }
+        A& operator=(const A &copy) { print_copy_assigned(this); v = copy.v; return *this; }
+        std::string toString() { return "A[" + std::to_string(v) + "]"; }
+    private:
+        int v;
+    };
     py::class_<A>(m_sub, "A")
         .def(py::init<int>())
         .def("__repr__", &A::toString);
 
+    class B {
+    public:
+        B() { print_default_created(this); }
+        ~B() { print_destroyed(this); }
+        B(const B&) { print_copy_created(this); }
+        B& operator=(const B &copy) { print_copy_assigned(this); a1 = copy.a1; a2 = copy.a2; return *this; }
+        A &get_a1() { return a1; }
+        A &get_a2() { return a2; }
+
+        A a1{1};
+        A a2{2};
+    };
     py::class_<B>(m_sub, "B")
         .def(py::init<>())
         .def("get_a1", &B::get_a1, "Return the internal A 1", py::return_value_policy::reference_internal)
@@ -55,4 +51,48 @@ test_initializer modules([](py::module &m) {
         .def_readwrite("a2", &B::a2);
 
     m.attr("OD") = py::module::import("collections").attr("OrderedDict");
-});
+
+    // test_duplicate_registration
+    // Registering two things with the same name
+    m.def("duplicate_registration", []() {
+        class Dupe1 { };
+        class Dupe2 { };
+        class Dupe3 { };
+        class DupeException { };
+
+        auto dm = py::module("dummy");
+        auto failures = py::list();
+
+        py::class_<Dupe1>(dm, "Dupe1");
+        py::class_<Dupe2>(dm, "Dupe2");
+        dm.def("dupe1_factory", []() { return Dupe1(); });
+        py::exception<DupeException>(dm, "DupeException");
+
+        try {
+            py::class_<Dupe1>(dm, "Dupe1");
+            failures.append("Dupe1 class");
+        } catch (std::runtime_error &) {}
+        try {
+            dm.def("Dupe1", []() { return Dupe1(); });
+            failures.append("Dupe1 function");
+        } catch (std::runtime_error &) {}
+        try {
+            py::class_<Dupe3>(dm, "dupe1_factory");
+            failures.append("dupe1_factory");
+        } catch (std::runtime_error &) {}
+        try {
+            py::exception<Dupe3>(dm, "Dupe2");
+            failures.append("Dupe2");
+        } catch (std::runtime_error &) {}
+        try {
+            dm.def("DupeException", []() { return 30; });
+            failures.append("DupeException1");
+        } catch (std::runtime_error &) {}
+        try {
+            py::class_<DupeException>(dm, "DupeException");
+            failures.append("DupeException2");
+        } catch (std::runtime_error &) {}
+
+        return failures;
+    });
+}
diff --git a/ext/pybind11/tests/test_modules.py b/ext/pybind11/tests/test_modules.py
index 69620949b..2552838c2 100644
--- a/ext/pybind11/tests/test_modules.py
+++ b/ext/pybind11/tests/test_modules.py
@@ -1,32 +1,34 @@
+from pybind11_tests import modules as m
+from pybind11_tests.modules import subsubmodule as ms
+from pybind11_tests import ConstructorStats
+
 
 def test_nested_modules():
     import pybind11_tests
-    from pybind11_tests.submodule import submodule_func
-
     assert pybind11_tests.__name__ == "pybind11_tests"
-    assert pybind11_tests.submodule.__name__ == "pybind11_tests.submodule"
+    assert pybind11_tests.modules.__name__ == "pybind11_tests.modules"
+    assert pybind11_tests.modules.subsubmodule.__name__ == "pybind11_tests.modules.subsubmodule"
+    assert m.__name__ == "pybind11_tests.modules"
+    assert ms.__name__ == "pybind11_tests.modules.subsubmodule"
 
-    assert submodule_func() == "submodule_func()"
+    assert ms.submodule_func() == "submodule_func()"
 
 
 def test_reference_internal():
-    from pybind11_tests import ConstructorStats
-    from pybind11_tests.submodule import A, B
-
-    b = B()
+    b = ms.B()
     assert str(b.get_a1()) == "A[1]"
     assert str(b.a1) == "A[1]"
     assert str(b.get_a2()) == "A[2]"
     assert str(b.a2) == "A[2]"
 
-    b.a1 = A(42)
-    b.a2 = A(43)
+    b.a1 = ms.A(42)
+    b.a2 = ms.A(43)
     assert str(b.get_a1()) == "A[42]"
     assert str(b.a1) == "A[42]"
     assert str(b.get_a2()) == "A[43]"
     assert str(b.a2) == "A[43]"
 
-    astats, bstats = ConstructorStats.get(A), ConstructorStats.get(B)
+    astats, bstats = ConstructorStats.get(ms.A), ConstructorStats.get(ms.B)
     assert astats.alive() == 2
     assert bstats.alive() == 1
     del b
@@ -47,7 +49,7 @@ def test_reference_internal():
 
 
 def test_importing():
-    from pybind11_tests import OD
+    from pybind11_tests.modules import OD
     from collections import OrderedDict
 
     assert OD is OrderedDict
@@ -59,4 +61,12 @@ def test_pydoc():
     import pybind11_tests
     import pydoc
 
+    assert pybind11_tests.__name__ == "pybind11_tests"
+    assert pybind11_tests.__doc__ == "pybind11 test module"
     assert pydoc.text.docmodule(pybind11_tests)
+
+
+def test_duplicate_registration():
+    """Registering two things with the same name"""
+
+    assert m.duplicate_registration() == []
diff --git a/ext/pybind11/tests/test_multiple_inheritance.cpp b/ext/pybind11/tests/test_multiple_inheritance.cpp
index 3ebeb202b..35f9d9c4e 100644
--- a/ext/pybind11/tests/test_multiple_inheritance.cpp
+++ b/ext/pybind11/tests/test_multiple_inheritance.cpp
@@ -9,41 +9,83 @@
 */
 
 #include "pybind11_tests.h"
+#include "constructor_stats.h"
 
-struct Base1 {
-    Base1(int i) : i(i) { }
-    int foo() { return i; }
+// Many bases for testing that multiple inheritance from many classes (i.e. requiring extra
+// space for holder constructed flags) works.
+template <int N> struct BaseN {
+    BaseN(int i) : i(i) { }
     int i;
 };
 
-struct Base2 {
-    Base2(int i) : i(i) { }
-    int bar() { return i; }
-    int i;
+// test_mi_static_properties
+struct Vanilla {
+    std::string vanilla() { return "Vanilla"; };
 };
-
-struct Base12 : Base1, Base2 {
-    Base12(int i, int j) : Base1(i), Base2(j) { }
+struct WithStatic1 {
+    static std::string static_func1() { return "WithStatic1"; };
+    static int static_value1;
 };
-
-struct MIType : Base12 {
-    MIType(int i, int j) : Base12(i, j) { }
+struct WithStatic2 {
+    static std::string static_func2() { return "WithStatic2"; };
+    static int static_value2;
 };
+struct VanillaStaticMix1 : Vanilla, WithStatic1, WithStatic2 {
+    static std::string static_func() { return "VanillaStaticMix1"; }
+    static int static_value;
+};
+struct VanillaStaticMix2 : WithStatic1, Vanilla, WithStatic2 {
+    static std::string static_func() { return "VanillaStaticMix2"; }
+    static int static_value;
+};
+int WithStatic1::static_value1 = 1;
+int WithStatic2::static_value2 = 2;
+int VanillaStaticMix1::static_value = 12;
+int VanillaStaticMix2::static_value = 12;
 
-test_initializer multiple_inheritance([](py::module &m) {
+TEST_SUBMODULE(multiple_inheritance, m) {
+
+    // test_multiple_inheritance_mix1
+    // test_multiple_inheritance_mix2
+    struct Base1 {
+        Base1(int i) : i(i) { }
+        int foo() { return i; }
+        int i;
+    };
     py::class_<Base1> b1(m, "Base1");
     b1.def(py::init<int>())
       .def("foo", &Base1::foo);
 
+    struct Base2 {
+        Base2(int i) : i(i) { }
+        int bar() { return i; }
+        int i;
+    };
     py::class_<Base2> b2(m, "Base2");
     b2.def(py::init<int>())
       .def("bar", &Base2::bar);
 
-    py::class_<Base12, Base1, Base2>(m, "Base12");
 
+    // test_multiple_inheritance_cpp
+    struct Base12 : Base1, Base2 {
+        Base12(int i, int j) : Base1(i), Base2(j) { }
+    };
+    struct MIType : Base12 {
+        MIType(int i, int j) : Base12(i, j) { }
+    };
+    py::class_<Base12, Base1, Base2>(m, "Base12");
     py::class_<MIType, Base12>(m, "MIType")
         .def(py::init<int, int>());
 
+
+    // test_multiple_inheritance_python_many_bases
+    #define PYBIND11_BASEN(N) py::class_<BaseN<N>>(m, "BaseN" #N).def(py::init<int>()).def("f" #N, [](BaseN<N> &b) { return b.i + N; })
+    PYBIND11_BASEN( 1); PYBIND11_BASEN( 2); PYBIND11_BASEN( 3); PYBIND11_BASEN( 4);
+    PYBIND11_BASEN( 5); PYBIND11_BASEN( 6); PYBIND11_BASEN( 7); PYBIND11_BASEN( 8);
+    PYBIND11_BASEN( 9); PYBIND11_BASEN(10); PYBIND11_BASEN(11); PYBIND11_BASEN(12);
+    PYBIND11_BASEN(13); PYBIND11_BASEN(14); PYBIND11_BASEN(15); PYBIND11_BASEN(16);
+    PYBIND11_BASEN(17);
+
     // Uncommenting this should result in a compile time failure (MI can only be specified via
     // template parameters because pybind has to know the types involved; see discussion in #742 for
     // details).
@@ -52,82 +94,78 @@ test_initializer multiple_inheritance([](py::module &m) {
 //    };
 //    py::class_<Base12v2>(m, "Base12v2", b1, b2)
 //        .def(py::init<int, int>());
-});
-
-/* Test the case where not all base classes are specified,
-   and where pybind11 requires the py::multiple_inheritance
-   flag to perform proper casting between types */
-
-struct Base1a {
-    Base1a(int i) : i(i) { }
-    int foo() { return i; }
-    int i;
-};
-
-struct Base2a {
-    Base2a(int i) : i(i) { }
-    int bar() { return i; }
-    int i;
-};
 
-struct Base12a : Base1a, Base2a {
-    Base12a(int i, int j) : Base1a(i), Base2a(j) { }
-};
 
-test_initializer multiple_inheritance_nonexplicit([](py::module &m) {
+    // test_multiple_inheritance_virtbase
+    // Test the case where not all base classes are specified, and where pybind11 requires the
+    // py::multiple_inheritance flag to perform proper casting between types.
+    struct Base1a {
+        Base1a(int i) : i(i) { }
+        int foo() { return i; }
+        int i;
+    };
     py::class_<Base1a, std::shared_ptr<Base1a>>(m, "Base1a")
         .def(py::init<int>())
         .def("foo", &Base1a::foo);
 
+    struct Base2a {
+        Base2a(int i) : i(i) { }
+        int bar() { return i; }
+        int i;
+    };
     py::class_<Base2a, std::shared_ptr<Base2a>>(m, "Base2a")
         .def(py::init<int>())
         .def("bar", &Base2a::bar);
 
+    struct Base12a : Base1a, Base2a {
+        Base12a(int i, int j) : Base1a(i), Base2a(j) { }
+    };
     py::class_<Base12a, /* Base1 missing */ Base2a,
                std::shared_ptr<Base12a>>(m, "Base12a", py::multiple_inheritance())
         .def(py::init<int, int>());
 
     m.def("bar_base2a", [](Base2a *b) { return b->bar(); });
     m.def("bar_base2a_sharedptr", [](std::shared_ptr<Base2a> b) { return b->bar(); });
-});
-
-struct Vanilla {
-    std::string vanilla() { return "Vanilla"; };
-};
-
-struct WithStatic1 {
-    static std::string static_func1() { return "WithStatic1"; };
-    static int static_value1;
-};
-
-struct WithStatic2 {
-    static std::string static_func2() { return "WithStatic2"; };
-    static int static_value2;
-};
-
-struct WithDict { };
-
-struct VanillaStaticMix1 : Vanilla, WithStatic1, WithStatic2 {
-    static std::string static_func() { return "VanillaStaticMix1"; }
-    static int static_value;
-};
-
-struct VanillaStaticMix2 : WithStatic1, Vanilla, WithStatic2 {
-    static std::string static_func() { return "VanillaStaticMix2"; }
-    static int static_value;
-};
-
-struct VanillaDictMix1 : Vanilla, WithDict { };
-struct VanillaDictMix2 : WithDict, Vanilla { };
-
-int WithStatic1::static_value1 = 1;
-int WithStatic2::static_value2 = 2;
-int VanillaStaticMix1::static_value = 12;
-int VanillaStaticMix2::static_value = 12;
-
-test_initializer mi_static_properties([](py::module &pm) {
-    auto m = pm.def_submodule("mi");
 
+    // test_mi_unaligned_base
+    // test_mi_base_return
+    // Issue #801: invalid casting to derived type with MI bases
+    struct I801B1 { int a = 1; virtual ~I801B1() = default; };
+    struct I801B2 { int b = 2; virtual ~I801B2() = default; };
+    struct I801C : I801B1, I801B2 {};
+    struct I801D : I801C {}; // Indirect MI
+    // Unregistered classes:
+    struct I801B3 { int c = 3; virtual ~I801B3() = default; };
+    struct I801E : I801B3, I801D {};
+
+    py::class_<I801B1, std::shared_ptr<I801B1>>(m, "I801B1").def(py::init<>()).def_readonly("a", &I801B1::a);
+    py::class_<I801B2, std::shared_ptr<I801B2>>(m, "I801B2").def(py::init<>()).def_readonly("b", &I801B2::b);
+    py::class_<I801C, I801B1, I801B2, std::shared_ptr<I801C>>(m, "I801C").def(py::init<>());
+    py::class_<I801D, I801C, std::shared_ptr<I801D>>(m, "I801D").def(py::init<>());
+
+    // Two separate issues here: first, we want to recognize a pointer to a base type as being a
+    // known instance even when the pointer value is unequal (i.e. due to a non-first
+    // multiple-inheritance base class):
+    m.def("i801b1_c", [](I801C *c) { return static_cast<I801B1 *>(c); });
+    m.def("i801b2_c", [](I801C *c) { return static_cast<I801B2 *>(c); });
+    m.def("i801b1_d", [](I801D *d) { return static_cast<I801B1 *>(d); });
+    m.def("i801b2_d", [](I801D *d) { return static_cast<I801B2 *>(d); });
+
+    // Second, when returned a base class pointer to a derived instance, we cannot assume that the
+    // pointer is `reinterpret_cast`able to the derived pointer because, like above, the base class
+    // pointer could be offset.
+    m.def("i801c_b1", []() -> I801B1 * { return new I801C(); });
+    m.def("i801c_b2", []() -> I801B2 * { return new I801C(); });
+    m.def("i801d_b1", []() -> I801B1 * { return new I801D(); });
+    m.def("i801d_b2", []() -> I801B2 * { return new I801D(); });
+
+    // Return a base class pointer to a pybind-registered type when the actual derived type
+    // isn't pybind-registered (and uses multiple-inheritance to offset the pybind base)
+    m.def("i801e_c", []() -> I801C * { return new I801E(); });
+    m.def("i801e_b2", []() -> I801B2 * { return new I801E(); });
+
+
+    // test_mi_static_properties
     py::class_<Vanilla>(m, "Vanilla")
         .def(py::init<>())
         .def("vanilla", &Vanilla::vanilla);
@@ -154,9 +192,29 @@ test_initializer mi_static_properties([](py::module &pm) {
         .def_static("static_func", &VanillaStaticMix2::static_func)
         .def_readwrite_static("static_value", &VanillaStaticMix2::static_value);
 
+
 #if !defined(PYPY_VERSION)
+    struct WithDict { };
+    struct VanillaDictMix1 : Vanilla, WithDict { };
+    struct VanillaDictMix2 : WithDict, Vanilla { };
     py::class_<WithDict>(m, "WithDict", py::dynamic_attr()).def(py::init<>());
     py::class_<VanillaDictMix1, Vanilla, WithDict>(m, "VanillaDictMix1").def(py::init<>());
     py::class_<VanillaDictMix2, WithDict, Vanilla>(m, "VanillaDictMix2").def(py::init<>());
 #endif
-});
+
+    // test_diamond_inheritance
+    // Issue #959: segfault when constructing diamond inheritance instance
+    // All of these have int members so that there will be various unequal pointers involved.
+    struct B { int b; virtual ~B() = default; };
+    struct C0 : public virtual B { int c0; };
+    struct C1 : public virtual B { int c1; };
+    struct D : public C0, public C1 { int d; };
+    py::class_<B>(m, "B")
+        .def("b", [](B *self) { return self; });
+    py::class_<C0, B>(m, "C0")
+        .def("c0", [](C0 *self) { return self; });
+    py::class_<C1, B>(m, "C1")
+        .def("c1", [](C1 *self) { return self; });
+    py::class_<D, C0, C1>(m, "D")
+        .def(py::init<>());
+}
diff --git a/ext/pybind11/tests/test_multiple_inheritance.py b/ext/pybind11/tests/test_multiple_inheritance.py
index 7aaab7cd0..475dd3b3d 100644
--- a/ext/pybind11/tests/test_multiple_inheritance.py
+++ b/ext/pybind11/tests/test_multiple_inheritance.py
@@ -1,18 +1,16 @@
 import pytest
+from pybind11_tests import ConstructorStats
+from pybind11_tests import multiple_inheritance as m
 
 
 def test_multiple_inheritance_cpp():
-    from pybind11_tests import MIType
-
-    mt = MIType(3, 4)
+    mt = m.MIType(3, 4)
 
     assert mt.foo() == 3
     assert mt.bar() == 4
 
 
 def test_multiple_inheritance_mix1():
-    from pybind11_tests import Base2
-
     class Base1:
         def __init__(self, i):
             self.i = i
@@ -20,10 +18,10 @@ def test_multiple_inheritance_mix1():
         def foo(self):
             return self.i
 
-    class MITypePy(Base1, Base2):
+    class MITypePy(Base1, m.Base2):
         def __init__(self, i, j):
             Base1.__init__(self, i)
-            Base2.__init__(self, j)
+            m.Base2.__init__(self, j)
 
     mt = MITypePy(3, 4)
 
@@ -32,7 +30,6 @@ def test_multiple_inheritance_mix1():
 
 
 def test_multiple_inheritance_mix2():
-    from pybind11_tests import Base1
 
     class Base2:
         def __init__(self, i):
@@ -41,9 +38,9 @@ def test_multiple_inheritance_mix2():
         def bar(self):
             return self.i
 
-    class MITypePy(Base1, Base2):
+    class MITypePy(m.Base1, Base2):
         def __init__(self, i, j):
-            Base1.__init__(self, i)
+            m.Base1.__init__(self, i)
             Base2.__init__(self, j)
 
     mt = MITypePy(3, 4)
@@ -52,43 +49,198 @@ def test_multiple_inheritance_mix2():
     assert mt.bar() == 4
 
 
-def test_multiple_inheritance_error():
-    """Inheriting from multiple C++ bases in Python is not supported"""
-    from pybind11_tests import Base1, Base2
+def test_multiple_inheritance_python():
+
+    class MI1(m.Base1, m.Base2):
+        def __init__(self, i, j):
+            m.Base1.__init__(self, i)
+            m.Base2.__init__(self, j)
+
+    class B1(object):
+        def v(self):
+            return 1
+
+    class MI2(B1, m.Base1, m.Base2):
+        def __init__(self, i, j):
+            B1.__init__(self)
+            m.Base1.__init__(self, i)
+            m.Base2.__init__(self, j)
+
+    class MI3(MI2):
+        def __init__(self, i, j):
+            MI2.__init__(self, i, j)
+
+    class MI4(MI3, m.Base2):
+        def __init__(self, i, j):
+            MI3.__init__(self, i, j)
+            # This should be ignored (Base2 is already initialized via MI2):
+            m.Base2.__init__(self, i + 100)
+
+    class MI5(m.Base2, B1, m.Base1):
+        def __init__(self, i, j):
+            B1.__init__(self)
+            m.Base1.__init__(self, i)
+            m.Base2.__init__(self, j)
+
+    class MI6(m.Base2, B1):
+        def __init__(self, i):
+            m.Base2.__init__(self, i)
+            B1.__init__(self)
+
+    class B2(B1):
+        def v(self):
+            return 2
+
+    class B3(object):
+        def v(self):
+            return 3
+
+    class B4(B3, B2):
+        def v(self):
+            return 4
+
+    class MI7(B4, MI6):
+        def __init__(self, i):
+            B4.__init__(self)
+            MI6.__init__(self, i)
+
+    class MI8(MI6, B3):
+        def __init__(self, i):
+            MI6.__init__(self, i)
+            B3.__init__(self)
 
-    with pytest.raises(TypeError) as excinfo:
-        # noinspection PyUnusedLocal
-        class MI(Base1, Base2):
-            pass
-    assert "Can't inherit from multiple C++ classes in Python" in str(excinfo.value)
+    class MI8b(B3, MI6):
+        def __init__(self, i):
+            B3.__init__(self)
+            MI6.__init__(self, i)
+
+    mi1 = MI1(1, 2)
+    assert mi1.foo() == 1
+    assert mi1.bar() == 2
+
+    mi2 = MI2(3, 4)
+    assert mi2.v() == 1
+    assert mi2.foo() == 3
+    assert mi2.bar() == 4
+
+    mi3 = MI3(5, 6)
+    assert mi3.v() == 1
+    assert mi3.foo() == 5
+    assert mi3.bar() == 6
+
+    mi4 = MI4(7, 8)
+    assert mi4.v() == 1
+    assert mi4.foo() == 7
+    assert mi4.bar() == 8
+
+    mi5 = MI5(10, 11)
+    assert mi5.v() == 1
+    assert mi5.foo() == 10
+    assert mi5.bar() == 11
+
+    mi6 = MI6(12)
+    assert mi6.v() == 1
+    assert mi6.bar() == 12
+
+    mi7 = MI7(13)
+    assert mi7.v() == 4
+    assert mi7.bar() == 13
+
+    mi8 = MI8(14)
+    assert mi8.v() == 1
+    assert mi8.bar() == 14
+
+    mi8b = MI8b(15)
+    assert mi8b.v() == 3
+    assert mi8b.bar() == 15
+
+
+def test_multiple_inheritance_python_many_bases():
+
+    class MIMany14(m.BaseN1, m.BaseN2, m.BaseN3, m.BaseN4):
+        def __init__(self):
+            m.BaseN1.__init__(self, 1)
+            m.BaseN2.__init__(self, 2)
+            m.BaseN3.__init__(self, 3)
+            m.BaseN4.__init__(self, 4)
+
+    class MIMany58(m.BaseN5, m.BaseN6, m.BaseN7, m.BaseN8):
+        def __init__(self):
+            m.BaseN5.__init__(self, 5)
+            m.BaseN6.__init__(self, 6)
+            m.BaseN7.__init__(self, 7)
+            m.BaseN8.__init__(self, 8)
+
+    class MIMany916(m.BaseN9, m.BaseN10, m.BaseN11, m.BaseN12, m.BaseN13, m.BaseN14, m.BaseN15,
+                    m.BaseN16):
+        def __init__(self):
+            m.BaseN9.__init__(self, 9)
+            m.BaseN10.__init__(self, 10)
+            m.BaseN11.__init__(self, 11)
+            m.BaseN12.__init__(self, 12)
+            m.BaseN13.__init__(self, 13)
+            m.BaseN14.__init__(self, 14)
+            m.BaseN15.__init__(self, 15)
+            m.BaseN16.__init__(self, 16)
+
+    class MIMany19(MIMany14, MIMany58, m.BaseN9):
+        def __init__(self):
+            MIMany14.__init__(self)
+            MIMany58.__init__(self)
+            m.BaseN9.__init__(self, 9)
+
+    class MIMany117(MIMany14, MIMany58, MIMany916, m.BaseN17):
+        def __init__(self):
+            MIMany14.__init__(self)
+            MIMany58.__init__(self)
+            MIMany916.__init__(self)
+            m.BaseN17.__init__(self, 17)
+
+    # Inherits from 4 registered C++ classes: can fit in one pointer on any modern arch:
+    a = MIMany14()
+    for i in range(1, 4):
+        assert getattr(a, "f" + str(i))() == 2 * i
+
+    # Inherits from 8: requires 1/2 pointers worth of holder flags on 32/64-bit arch:
+    b = MIMany916()
+    for i in range(9, 16):
+        assert getattr(b, "f" + str(i))() == 2 * i
+
+    # Inherits from 9: requires >= 2 pointers worth of holder flags
+    c = MIMany19()
+    for i in range(1, 9):
+        assert getattr(c, "f" + str(i))() == 2 * i
+
+    # Inherits from 17: requires >= 3 pointers worth of holder flags
+    d = MIMany117()
+    for i in range(1, 17):
+        assert getattr(d, "f" + str(i))() == 2 * i
 
 
 def test_multiple_inheritance_virtbase():
-    from pybind11_tests import Base12a, bar_base2a, bar_base2a_sharedptr
 
-    class MITypePy(Base12a):
+    class MITypePy(m.Base12a):
         def __init__(self, i, j):
-            Base12a.__init__(self, i, j)
+            m.Base12a.__init__(self, i, j)
 
     mt = MITypePy(3, 4)
     assert mt.bar() == 4
-    assert bar_base2a(mt) == 4
-    assert bar_base2a_sharedptr(mt) == 4
+    assert m.bar_base2a(mt) == 4
+    assert m.bar_base2a_sharedptr(mt) == 4
 
 
 def test_mi_static_properties():
     """Mixing bases with and without static properties should be possible
      and the result should be independent of base definition order"""
-    from pybind11_tests import mi
 
-    for d in (mi.VanillaStaticMix1(), mi.VanillaStaticMix2()):
+    for d in (m.VanillaStaticMix1(), m.VanillaStaticMix2()):
         assert d.vanilla() == "Vanilla"
         assert d.static_func1() == "WithStatic1"
         assert d.static_func2() == "WithStatic2"
         assert d.static_func() == d.__class__.__name__
 
-        mi.WithStatic1.static_value1 = 1
-        mi.WithStatic2.static_value2 = 2
+        m.WithStatic1.static_value1 = 1
+        m.WithStatic2.static_value2 = 2
         assert d.static_value1 == 1
         assert d.static_value2 == 2
         assert d.static_value == 12
@@ -104,8 +256,94 @@ def test_mi_static_properties():
 @pytest.unsupported_on_pypy
 def test_mi_dynamic_attributes():
     """Mixing bases with and without dynamic attribute support"""
-    from pybind11_tests import mi
 
-    for d in (mi.VanillaDictMix1(), mi.VanillaDictMix2()):
+    for d in (m.VanillaDictMix1(), m.VanillaDictMix2()):
         d.dynamic = 1
         assert d.dynamic == 1
+
+
+def test_mi_unaligned_base():
+    """Returning an offset (non-first MI) base class pointer should recognize the instance"""
+
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    c = m.I801C()
+    d = m.I801D()
+    # + 4 below because we have the two instances, and each instance has offset base I801B2
+    assert ConstructorStats.detail_reg_inst() == n_inst + 4
+    b1c = m.i801b1_c(c)
+    assert b1c is c
+    b2c = m.i801b2_c(c)
+    assert b2c is c
+    b1d = m.i801b1_d(d)
+    assert b1d is d
+    b2d = m.i801b2_d(d)
+    assert b2d is d
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 4  # no extra instances
+    del c, b1c, b2c
+    assert ConstructorStats.detail_reg_inst() == n_inst + 2
+    del d, b1d, b2d
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+
+def test_mi_base_return():
+    """Tests returning an offset (non-first MI) base class pointer to a derived instance"""
+
+    n_inst = ConstructorStats.detail_reg_inst()
+
+    c1 = m.i801c_b1()
+    assert type(c1) is m.I801C
+    assert c1.a == 1
+    assert c1.b == 2
+
+    d1 = m.i801d_b1()
+    assert type(d1) is m.I801D
+    assert d1.a == 1
+    assert d1.b == 2
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 4
+
+    c2 = m.i801c_b2()
+    assert type(c2) is m.I801C
+    assert c2.a == 1
+    assert c2.b == 2
+
+    d2 = m.i801d_b2()
+    assert type(d2) is m.I801D
+    assert d2.a == 1
+    assert d2.b == 2
+
+    assert ConstructorStats.detail_reg_inst() == n_inst + 8
+
+    del c2
+    assert ConstructorStats.detail_reg_inst() == n_inst + 6
+    del c1, d1, d2
+    assert ConstructorStats.detail_reg_inst() == n_inst
+
+    # Returning an unregistered derived type with a registered base; we won't
+    # pick up the derived type, obviously, but should still work (as an object
+    # of whatever type was returned).
+    e1 = m.i801e_c()
+    assert type(e1) is m.I801C
+    assert e1.a == 1
+    assert e1.b == 2
+
+    e2 = m.i801e_b2()
+    assert type(e2) is m.I801B2
+    assert e2.b == 2
+
+
+def test_diamond_inheritance():
+    """Tests that diamond inheritance works as expected (issue #959)"""
+
+    # Issue #959: this shouldn't segfault:
+    d = m.D()
+
+    # Make sure all the various distinct pointers are all recognized as registered instances:
+    assert d is d.c0()
+    assert d is d.c1()
+    assert d is d.b()
+    assert d is d.c0().b()
+    assert d is d.c1().b()
+    assert d is d.c0().c1().b().c0().b()
diff --git a/ext/pybind11/tests/test_numpy_array.cpp b/ext/pybind11/tests/test_numpy_array.cpp
index cd6487249..2046c0e03 100644
--- a/ext/pybind11/tests/test_numpy_array.cpp
+++ b/ext/pybind11/tests/test_numpy_array.cpp
@@ -13,7 +13,6 @@
 #include <pybind11/stl.h>
 
 #include <cstdint>
-#include <vector>
 
 using arr = py::array;
 using arr_t = py::array_t<uint16_t, 0>;
@@ -27,39 +26,25 @@ template<typename... Ix> arr data_t(const arr_t& a, Ix... index) {
     return arr(a.size() - a.index_at(index...), a.data(index...));
 }
 
-arr& mutate_data(arr& a) {
-    auto ptr = (uint8_t *) a.mutable_data();
-    for (size_t i = 0; i < a.nbytes(); i++)
-        ptr[i] = (uint8_t) (ptr[i] * 2);
-    return a;
-}
-
-arr_t& mutate_data_t(arr_t& a) {
-    auto ptr = a.mutable_data();
-    for (size_t i = 0; i < a.size(); i++)
-        ptr[i]++;
-    return a;
-}
-
 template<typename... Ix> arr& mutate_data(arr& a, Ix... index) {
     auto ptr = (uint8_t *) a.mutable_data(index...);
-    for (size_t i = 0; i < a.nbytes() - a.offset_at(index...); i++)
+    for (ssize_t i = 0; i < a.nbytes() - a.offset_at(index...); i++)
         ptr[i] = (uint8_t) (ptr[i] * 2);
     return a;
 }
 
 template<typename... Ix> arr_t& mutate_data_t(arr_t& a, Ix... index) {
     auto ptr = a.mutable_data(index...);
-    for (size_t i = 0; i < a.size() - a.index_at(index...); i++)
+    for (ssize_t i = 0; i < a.size() - a.index_at(index...); i++)
         ptr[i]++;
     return a;
 }
 
-template<typename... Ix> size_t index_at(const arr& a, Ix... idx) { return a.index_at(idx...); }
-template<typename... Ix> size_t index_at_t(const arr_t& a, Ix... idx) { return a.index_at(idx...); }
-template<typename... Ix> size_t offset_at(const arr& a, Ix... idx) { return a.offset_at(idx...); }
-template<typename... Ix> size_t offset_at_t(const arr_t& a, Ix... idx) { return a.offset_at(idx...); }
-template<typename... Ix> size_t at_t(const arr_t& a, Ix... idx) { return a.at(idx...); }
+template<typename... Ix> ssize_t index_at(const arr& a, Ix... idx) { return a.index_at(idx...); }
+template<typename... Ix> ssize_t index_at_t(const arr_t& a, Ix... idx) { return a.index_at(idx...); }
+template<typename... Ix> ssize_t offset_at(const arr& a, Ix... idx) { return a.offset_at(idx...); }
+template<typename... Ix> ssize_t offset_at_t(const arr_t& a, Ix... idx) { return a.offset_at(idx...); }
+template<typename... Ix> ssize_t at_t(const arr_t& a, Ix... idx) { return a.at(idx...); }
 template<typename... Ix> arr_t& mutate_at_t(arr_t& a, Ix... idx) { a.mutable_at(idx...)++; return a; }
 
 #define def_index_fn(name, type) \
@@ -83,55 +68,57 @@ template <typename T, typename T2> py::handle auxiliaries(T &&r, T2 &&r2) {
     return l.release();
 }
 
-test_initializer numpy_array([](py::module &m) {
-    auto sm = m.def_submodule("array");
+TEST_SUBMODULE(numpy_array, sm) {
+    try { py::module::import("numpy"); }
+    catch (...) { return; }
 
+    // test_array_attributes
     sm.def("ndim", [](const arr& a) { return a.ndim(); });
     sm.def("shape", [](const arr& a) { return arr(a.ndim(), a.shape()); });
-    sm.def("shape", [](const arr& a, size_t dim) { return a.shape(dim); });
+    sm.def("shape", [](const arr& a, ssize_t dim) { return a.shape(dim); });
     sm.def("strides", [](const arr& a) { return arr(a.ndim(), a.strides()); });
-    sm.def("strides", [](const arr& a, size_t dim) { return a.strides(dim); });
+    sm.def("strides", [](const arr& a, ssize_t dim) { return a.strides(dim); });
     sm.def("writeable", [](const arr& a) { return a.writeable(); });
     sm.def("size", [](const arr& a) { return a.size(); });
     sm.def("itemsize", [](const arr& a) { return a.itemsize(); });
     sm.def("nbytes", [](const arr& a) { return a.nbytes(); });
     sm.def("owndata", [](const arr& a) { return a.owndata(); });
 
-    def_index_fn(data, const arr&);
-    def_index_fn(data_t, const arr_t&);
+    // test_index_offset
     def_index_fn(index_at, const arr&);
     def_index_fn(index_at_t, const arr_t&);
     def_index_fn(offset_at, const arr&);
     def_index_fn(offset_at_t, const arr_t&);
+    // test_data
+    def_index_fn(data, const arr&);
+    def_index_fn(data_t, const arr_t&);
+    // test_mutate_data, test_mutate_readonly
     def_index_fn(mutate_data, arr&);
     def_index_fn(mutate_data_t, arr_t&);
     def_index_fn(at_t, const arr_t&);
     def_index_fn(mutate_at_t, arr_t&);
 
-    sm.def("make_f_array", [] {
-        return py::array_t<float>({ 2, 2 }, { 4, 8 });
-    });
-
-    sm.def("make_c_array", [] {
-        return py::array_t<float>({ 2, 2 }, { 8, 4 });
-    });
+    // test_make_c_f_array
+    sm.def("make_f_array", [] { return py::array_t<float>({ 2, 2 }, { 4, 8 }); });
+    sm.def("make_c_array", [] { return py::array_t<float>({ 2, 2 }, { 8, 4 }); });
 
+    // test_wrap
     sm.def("wrap", [](py::array a) {
         return py::array(
             a.dtype(),
-            std::vector<size_t>(a.shape(), a.shape() + a.ndim()),
-            std::vector<size_t>(a.strides(), a.strides() + a.ndim()),
+            {a.shape(), a.shape() + a.ndim()},
+            {a.strides(), a.strides() + a.ndim()},
             a.data(),
             a
         );
     });
 
+    // test_numpy_view
     struct ArrayClass {
         int data[2] = { 1, 2 };
         ArrayClass() { py::print("ArrayClass()"); }
         ~ArrayClass() { py::print("~ArrayClass()"); }
     };
-
     py::class_<ArrayClass>(sm, "ArrayClass")
         .def(py::init<>())
         .def("numpy_view", [](py::object &obj) {
@@ -141,16 +128,18 @@ test_initializer numpy_array([](py::module &m) {
         }
     );
 
+    // test_cast_numpy_int64_to_uint64
     sm.def("function_taking_uint64", [](uint64_t) { });
 
+    // test_isinstance
     sm.def("isinstance_untyped", [](py::object yes, py::object no) {
         return py::isinstance<py::array>(yes) && !py::isinstance<py::array>(no);
     });
-
     sm.def("isinstance_typed", [](py::object o) {
         return py::isinstance<py::array_t<double>>(o) && !py::isinstance<py::array_t<int>>(o);
     });
 
+    // test_constructors
     sm.def("default_constructors", []() {
         return py::dict(
             "array"_a=py::array(),
@@ -158,7 +147,6 @@ test_initializer numpy_array([](py::module &m) {
             "array_t<double>"_a=py::array_t<double>()
         );
     });
-
     sm.def("converting_constructors", [](py::object o) {
         return py::dict(
             "array"_a=py::array(o),
@@ -167,7 +155,7 @@ test_initializer numpy_array([](py::module &m) {
         );
     });
 
-    // Overload resolution tests:
+    // test_overload_resolution
     sm.def("overloaded", [](py::array_t<double>) { return "double"; });
     sm.def("overloaded", [](py::array_t<float>) { return "float"; });
     sm.def("overloaded", [](py::array_t<int>) { return "int"; });
@@ -195,40 +183,42 @@ test_initializer numpy_array([](py::module &m) {
     sm.def("overloaded5", [](py::array_t<unsigned int>) { return "unsigned int"; });
     sm.def("overloaded5", [](py::array_t<double>) { return "double"; });
 
+    // test_greedy_string_overload
     // Issue 685: ndarray shouldn't go to std::string overload
     sm.def("issue685", [](std::string) { return "string"; });
     sm.def("issue685", [](py::array) { return "array"; });
     sm.def("issue685", [](py::object) { return "other"; });
 
+    // test_array_unchecked_fixed_dims
     sm.def("proxy_add2", [](py::array_t<double> a, double v) {
         auto r = a.mutable_unchecked<2>();
-        for (size_t i = 0; i < r.shape(0); i++)
-            for (size_t j = 0; j < r.shape(1); j++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
+            for (ssize_t j = 0; j < r.shape(1); j++)
                 r(i, j) += v;
     }, py::arg().noconvert(), py::arg());
 
     sm.def("proxy_init3", [](double start) {
         py::array_t<double, py::array::c_style> a({ 3, 3, 3 });
         auto r = a.mutable_unchecked<3>();
-        for (size_t i = 0; i < r.shape(0); i++)
-        for (size_t j = 0; j < r.shape(1); j++)
-        for (size_t k = 0; k < r.shape(2); k++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
+        for (ssize_t j = 0; j < r.shape(1); j++)
+        for (ssize_t k = 0; k < r.shape(2); k++)
             r(i, j, k) = start++;
         return a;
     });
     sm.def("proxy_init3F", [](double start) {
         py::array_t<double, py::array::f_style> a({ 3, 3, 3 });
         auto r = a.mutable_unchecked<3>();
-        for (size_t k = 0; k < r.shape(2); k++)
-        for (size_t j = 0; j < r.shape(1); j++)
-        for (size_t i = 0; i < r.shape(0); i++)
+        for (ssize_t k = 0; k < r.shape(2); k++)
+        for (ssize_t j = 0; j < r.shape(1); j++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
             r(i, j, k) = start++;
         return a;
     });
     sm.def("proxy_squared_L2_norm", [](py::array_t<double> a) {
         auto r = a.unchecked<1>();
         double sumsq = 0;
-        for (size_t i = 0; i < r.shape(0); i++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
             sumsq += r[i] * r(i); // Either notation works for a 1D array
         return sumsq;
     });
@@ -239,21 +229,22 @@ test_initializer numpy_array([](py::module &m) {
         return auxiliaries(r, r2);
     });
 
+    // test_array_unchecked_dyn_dims
     // Same as the above, but without a compile-time dimensions specification:
     sm.def("proxy_add2_dyn", [](py::array_t<double> a, double v) {
         auto r = a.mutable_unchecked();
         if (r.ndim() != 2) throw std::domain_error("error: ndim != 2");
-        for (size_t i = 0; i < r.shape(0); i++)
-            for (size_t j = 0; j < r.shape(1); j++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
+            for (ssize_t j = 0; j < r.shape(1); j++)
                 r(i, j) += v;
     }, py::arg().noconvert(), py::arg());
     sm.def("proxy_init3_dyn", [](double start) {
         py::array_t<double, py::array::c_style> a({ 3, 3, 3 });
         auto r = a.mutable_unchecked();
         if (r.ndim() != 3) throw std::domain_error("error: ndim != 3");
-        for (size_t i = 0; i < r.shape(0); i++)
-        for (size_t j = 0; j < r.shape(1); j++)
-        for (size_t k = 0; k < r.shape(2); k++)
+        for (ssize_t i = 0; i < r.shape(0); i++)
+        for (ssize_t j = 0; j < r.shape(1); j++)
+        for (ssize_t k = 0; k < r.shape(2); k++)
             r(i, j, k) = start++;
         return a;
     });
@@ -264,4 +255,41 @@ test_initializer numpy_array([](py::module &m) {
     sm.def("array_auxiliaries2", [](py::array_t<double> a) {
         return auxiliaries(a, a);
     });
-});
+
+    // test_array_failures
+    // Issue #785: Uninformative "Unknown internal error" exception when constructing array from empty object:
+    sm.def("array_fail_test", []() { return py::array(py::object()); });
+    sm.def("array_t_fail_test", []() { return py::array_t<double>(py::object()); });
+    // Make sure the error from numpy is being passed through:
+    sm.def("array_fail_test_negative_size", []() { int c = 0; return py::array(-1, &c); });
+
+    // test_initializer_list
+    // Issue (unnumbered; reported in #788): regression: initializer lists can be ambiguous
+    sm.def("array_initializer_list1", []() { return py::array_t<float>(1); }); // { 1 } also works, but clang warns about it
+    sm.def("array_initializer_list2", []() { return py::array_t<float>({ 1, 2 }); });
+    sm.def("array_initializer_list3", []() { return py::array_t<float>({ 1, 2, 3 }); });
+    sm.def("array_initializer_list4", []() { return py::array_t<float>({ 1, 2, 3, 4 }); });
+
+    // test_array_resize
+    // reshape array to 2D without changing size
+    sm.def("array_reshape2", [](py::array_t<double> a) {
+        const ssize_t dim_sz = (ssize_t)std::sqrt(a.size());
+        if (dim_sz * dim_sz != a.size())
+            throw std::domain_error("array_reshape2: input array total size is not a squared integer");
+        a.resize({dim_sz, dim_sz});
+    });
+
+    // resize to 3D array with each dimension = N
+    sm.def("array_resize3", [](py::array_t<double> a, size_t N, bool refcheck) {
+        a.resize({N, N, N}, refcheck);
+    });
+
+    // test_array_create_and_resize
+    // return 2D array with Nrows = Ncols = N
+    sm.def("create_and_resize", [](size_t N) {
+        py::array_t<double> a;
+        a.resize({N, N});
+        std::fill(a.mutable_data(), a.mutable_data() + a.size(), 42.);
+        return a;
+    });
+}
diff --git a/ext/pybind11/tests/test_numpy_array.py b/ext/pybind11/tests/test_numpy_array.py
index 14c25b371..27433934f 100644
--- a/ext/pybind11/tests/test_numpy_array.py
+++ b/ext/pybind11/tests/test_numpy_array.py
@@ -1,4 +1,5 @@
 import pytest
+from pybind11_tests import numpy_array as m
 
 pytestmark = pytest.requires_numpy
 
@@ -12,62 +13,55 @@ def arr():
 
 
 def test_array_attributes():
-    from pybind11_tests.array import (
-        ndim, shape, strides, writeable, size, itemsize, nbytes, owndata
-    )
-
     a = np.array(0, 'f8')
-    assert ndim(a) == 0
-    assert all(shape(a) == [])
-    assert all(strides(a) == [])
+    assert m.ndim(a) == 0
+    assert all(m.shape(a) == [])
+    assert all(m.strides(a) == [])
     with pytest.raises(IndexError) as excinfo:
-        shape(a, 0)
+        m.shape(a, 0)
     assert str(excinfo.value) == 'invalid axis: 0 (ndim = 0)'
     with pytest.raises(IndexError) as excinfo:
-        strides(a, 0)
+        m.strides(a, 0)
     assert str(excinfo.value) == 'invalid axis: 0 (ndim = 0)'
-    assert writeable(a)
-    assert size(a) == 1
-    assert itemsize(a) == 8
-    assert nbytes(a) == 8
-    assert owndata(a)
+    assert m.writeable(a)
+    assert m.size(a) == 1
+    assert m.itemsize(a) == 8
+    assert m.nbytes(a) == 8
+    assert m.owndata(a)
 
     a = np.array([[1, 2, 3], [4, 5, 6]], 'u2').view()
     a.flags.writeable = False
-    assert ndim(a) == 2
-    assert all(shape(a) == [2, 3])
-    assert shape(a, 0) == 2
-    assert shape(a, 1) == 3
-    assert all(strides(a) == [6, 2])
-    assert strides(a, 0) == 6
-    assert strides(a, 1) == 2
+    assert m.ndim(a) == 2
+    assert all(m.shape(a) == [2, 3])
+    assert m.shape(a, 0) == 2
+    assert m.shape(a, 1) == 3
+    assert all(m.strides(a) == [6, 2])
+    assert m.strides(a, 0) == 6
+    assert m.strides(a, 1) == 2
     with pytest.raises(IndexError) as excinfo:
-        shape(a, 2)
+        m.shape(a, 2)
     assert str(excinfo.value) == 'invalid axis: 2 (ndim = 2)'
     with pytest.raises(IndexError) as excinfo:
-        strides(a, 2)
+        m.strides(a, 2)
     assert str(excinfo.value) == 'invalid axis: 2 (ndim = 2)'
-    assert not writeable(a)
-    assert size(a) == 6
-    assert itemsize(a) == 2
-    assert nbytes(a) == 12
-    assert not owndata(a)
+    assert not m.writeable(a)
+    assert m.size(a) == 6
+    assert m.itemsize(a) == 2
+    assert m.nbytes(a) == 12
+    assert not m.owndata(a)
 
 
 @pytest.mark.parametrize('args, ret', [([], 0), ([0], 0), ([1], 3), ([0, 1], 1), ([1, 2], 5)])
 def test_index_offset(arr, args, ret):
-    from pybind11_tests.array import index_at, index_at_t, offset_at, offset_at_t
-    assert index_at(arr, *args) == ret
-    assert index_at_t(arr, *args) == ret
-    assert offset_at(arr, *args) == ret * arr.dtype.itemsize
-    assert offset_at_t(arr, *args) == ret * arr.dtype.itemsize
+    assert m.index_at(arr, *args) == ret
+    assert m.index_at_t(arr, *args) == ret
+    assert m.offset_at(arr, *args) == ret * arr.dtype.itemsize
+    assert m.offset_at_t(arr, *args) == ret * arr.dtype.itemsize
 
 
 def test_dim_check_fail(arr):
-    from pybind11_tests.array import (index_at, index_at_t, offset_at, offset_at_t, data, data_t,
-                                      mutate_data, mutate_data_t)
-    for func in (index_at, index_at_t, offset_at, offset_at_t, data, data_t,
-                 mutate_data, mutate_data_t):
+    for func in (m.index_at, m.index_at_t, m.offset_at, m.offset_at_t, m.data, m.data_t,
+                 m.mutate_data, m.mutate_data_t):
         with pytest.raises(IndexError) as excinfo:
             func(arr, 1, 2, 3)
         assert str(excinfo.value) == 'too many indices for an array: 3 (ndim = 2)'
@@ -79,63 +73,53 @@ def test_dim_check_fail(arr):
                           ([0, 1], [2, 3, 4, 5, 6]),
                           ([1, 2], [6])])
 def test_data(arr, args, ret):
-    from pybind11_tests.array import data, data_t
     from sys import byteorder
-    assert all(data_t(arr, *args) == ret)
-    assert all(data(arr, *args)[(0 if byteorder == 'little' else 1)::2] == ret)
-    assert all(data(arr, *args)[(1 if byteorder == 'little' else 0)::2] == 0)
-
-
-def test_mutate_readonly(arr):
-    from pybind11_tests.array import mutate_data, mutate_data_t, mutate_at_t
-    arr.flags.writeable = False
-    for func, args in (mutate_data, ()), (mutate_data_t, ()), (mutate_at_t, (0, 0)):
-        with pytest.raises(ValueError) as excinfo:
-            func(arr, *args)
-        assert str(excinfo.value) == 'array is not writeable'
+    assert all(m.data_t(arr, *args) == ret)
+    assert all(m.data(arr, *args)[(0 if byteorder == 'little' else 1)::2] == ret)
+    assert all(m.data(arr, *args)[(1 if byteorder == 'little' else 0)::2] == 0)
 
 
 @pytest.mark.parametrize('dim', [0, 1, 3])
 def test_at_fail(arr, dim):
-    from pybind11_tests.array import at_t, mutate_at_t
-    for func in at_t, mutate_at_t:
+    for func in m.at_t, m.mutate_at_t:
         with pytest.raises(IndexError) as excinfo:
             func(arr, *([0] * dim))
         assert str(excinfo.value) == 'index dimension mismatch: {} (ndim = 2)'.format(dim)
 
 
 def test_at(arr):
-    from pybind11_tests.array import at_t, mutate_at_t
+    assert m.at_t(arr, 0, 2) == 3
+    assert m.at_t(arr, 1, 0) == 4
 
-    assert at_t(arr, 0, 2) == 3
-    assert at_t(arr, 1, 0) == 4
+    assert all(m.mutate_at_t(arr, 0, 2).ravel() == [1, 2, 4, 4, 5, 6])
+    assert all(m.mutate_at_t(arr, 1, 0).ravel() == [1, 2, 4, 5, 5, 6])
 
-    assert all(mutate_at_t(arr, 0, 2).ravel() == [1, 2, 4, 4, 5, 6])
-    assert all(mutate_at_t(arr, 1, 0).ravel() == [1, 2, 4, 5, 5, 6])
 
+def test_mutate_readonly(arr):
+    arr.flags.writeable = False
+    for func, args in (m.mutate_data, ()), (m.mutate_data_t, ()), (m.mutate_at_t, (0, 0)):
+        with pytest.raises(ValueError) as excinfo:
+            func(arr, *args)
+        assert str(excinfo.value) == 'array is not writeable'
 
-def test_mutate_data(arr):
-    from pybind11_tests.array import mutate_data, mutate_data_t
 
-    assert all(mutate_data(arr).ravel() == [2, 4, 6, 8, 10, 12])
-    assert all(mutate_data(arr).ravel() == [4, 8, 12, 16, 20, 24])
-    assert all(mutate_data(arr, 1).ravel() == [4, 8, 12, 32, 40, 48])
-    assert all(mutate_data(arr, 0, 1).ravel() == [4, 16, 24, 64, 80, 96])
-    assert all(mutate_data(arr, 1, 2).ravel() == [4, 16, 24, 64, 80, 192])
+def test_mutate_data(arr):
+    assert all(m.mutate_data(arr).ravel() == [2, 4, 6, 8, 10, 12])
+    assert all(m.mutate_data(arr).ravel() == [4, 8, 12, 16, 20, 24])
+    assert all(m.mutate_data(arr, 1).ravel() == [4, 8, 12, 32, 40, 48])
+    assert all(m.mutate_data(arr, 0, 1).ravel() == [4, 16, 24, 64, 80, 96])
+    assert all(m.mutate_data(arr, 1, 2).ravel() == [4, 16, 24, 64, 80, 192])
 
-    assert all(mutate_data_t(arr).ravel() == [5, 17, 25, 65, 81, 193])
-    assert all(mutate_data_t(arr).ravel() == [6, 18, 26, 66, 82, 194])
-    assert all(mutate_data_t(arr, 1).ravel() == [6, 18, 26, 67, 83, 195])
-    assert all(mutate_data_t(arr, 0, 1).ravel() == [6, 19, 27, 68, 84, 196])
-    assert all(mutate_data_t(arr, 1, 2).ravel() == [6, 19, 27, 68, 84, 197])
+    assert all(m.mutate_data_t(arr).ravel() == [5, 17, 25, 65, 81, 193])
+    assert all(m.mutate_data_t(arr).ravel() == [6, 18, 26, 66, 82, 194])
+    assert all(m.mutate_data_t(arr, 1).ravel() == [6, 18, 26, 67, 83, 195])
+    assert all(m.mutate_data_t(arr, 0, 1).ravel() == [6, 19, 27, 68, 84, 196])
+    assert all(m.mutate_data_t(arr, 1, 2).ravel() == [6, 19, 27, 68, 84, 197])
 
 
 def test_bounds_check(arr):
-    from pybind11_tests.array import (index_at, index_at_t, data, data_t,
-                                      mutate_data, mutate_data_t, at_t, mutate_at_t)
-    funcs = (index_at, index_at_t, data, data_t,
-             mutate_data, mutate_data_t, at_t, mutate_at_t)
-    for func in funcs:
+    for func in (m.index_at, m.index_at_t, m.data, m.data_t,
+                 m.mutate_data, m.mutate_data_t, m.at_t, m.mutate_at_t):
         with pytest.raises(IndexError) as excinfo:
             func(arr, 2, 0)
         assert str(excinfo.value) == 'index 2 is out of bounds for axis 0 with size 2'
@@ -145,18 +129,13 @@ def test_bounds_check(arr):
 
 
 def test_make_c_f_array():
-    from pybind11_tests.array import (
-        make_c_array, make_f_array
-    )
-    assert make_c_array().flags.c_contiguous
-    assert not make_c_array().flags.f_contiguous
-    assert make_f_array().flags.f_contiguous
-    assert not make_f_array().flags.c_contiguous
+    assert m.make_c_array().flags.c_contiguous
+    assert not m.make_c_array().flags.f_contiguous
+    assert m.make_f_array().flags.f_contiguous
+    assert not m.make_f_array().flags.c_contiguous
 
 
 def test_wrap():
-    from pybind11_tests.array import wrap
-
     def assert_references(a, b, base=None):
         if base is None:
             base = a
@@ -178,36 +157,39 @@ def test_wrap():
 
     a1 = np.array([1, 2], dtype=np.int16)
     assert a1.flags.owndata and a1.base is None
-    a2 = wrap(a1)
+    a2 = m.wrap(a1)
     assert_references(a1, a2)
 
     a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order='F')
     assert a1.flags.owndata and a1.base is None
-    a2 = wrap(a1)
+    a2 = m.wrap(a1)
     assert_references(a1, a2)
 
     a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order='C')
     a1.flags.writeable = False
-    a2 = wrap(a1)
+    a2 = m.wrap(a1)
     assert_references(a1, a2)
 
     a1 = np.random.random((4, 4, 4))
-    a2 = wrap(a1)
+    a2 = m.wrap(a1)
     assert_references(a1, a2)
 
     a1t = a1.transpose()
-    a2 = wrap(a1t)
+    a2 = m.wrap(a1t)
     assert_references(a1t, a2, a1)
 
     a1d = a1.diagonal()
-    a2 = wrap(a1d)
+    a2 = m.wrap(a1d)
     assert_references(a1d, a2, a1)
 
+    a1m = a1[::-1, ::-1, ::-1]
+    a2 = m.wrap(a1m)
+    assert_references(a1m, a2, a1)
+
 
 def test_numpy_view(capture):
-    from pybind11_tests.array import ArrayClass
     with capture:
-        ac = ArrayClass()
+        ac = m.ArrayClass()
         ac_view_1 = ac.numpy_view()
         ac_view_2 = ac.numpy_view()
         assert np.all(ac_view_1 == np.array([1, 2], dtype=np.int32))
@@ -234,29 +216,24 @@ def test_numpy_view(capture):
 
 @pytest.unsupported_on_pypy
 def test_cast_numpy_int64_to_uint64():
-    from pybind11_tests.array import function_taking_uint64
-    function_taking_uint64(123)
-    function_taking_uint64(np.uint64(123))
+    m.function_taking_uint64(123)
+    m.function_taking_uint64(np.uint64(123))
 
 
 def test_isinstance():
-    from pybind11_tests.array import isinstance_untyped, isinstance_typed
-
-    assert isinstance_untyped(np.array([1, 2, 3]), "not an array")
-    assert isinstance_typed(np.array([1.0, 2.0, 3.0]))
+    assert m.isinstance_untyped(np.array([1, 2, 3]), "not an array")
+    assert m.isinstance_typed(np.array([1.0, 2.0, 3.0]))
 
 
 def test_constructors():
-    from pybind11_tests.array import default_constructors, converting_constructors
-
-    defaults = default_constructors()
+    defaults = m.default_constructors()
     for a in defaults.values():
         assert a.size == 0
     assert defaults["array"].dtype == np.array([]).dtype
     assert defaults["array_t<int32>"].dtype == np.int32
     assert defaults["array_t<double>"].dtype == np.float64
 
-    results = converting_constructors([1, 2, 3])
+    results = m.converting_constructors([1, 2, 3])
     for a in results.values():
         np.testing.assert_array_equal(a, [1, 2, 3])
     assert results["array"].dtype == np.int_
@@ -265,22 +242,20 @@ def test_constructors():
 
 
 def test_overload_resolution(msg):
-    from pybind11_tests.array import overloaded, overloaded2, overloaded3, overloaded4, overloaded5
-
     # Exact overload matches:
-    assert overloaded(np.array([1], dtype='float64')) == 'double'
-    assert overloaded(np.array([1], dtype='float32')) == 'float'
-    assert overloaded(np.array([1], dtype='ushort')) == 'unsigned short'
-    assert overloaded(np.array([1], dtype='intc')) == 'int'
-    assert overloaded(np.array([1], dtype='longlong')) == 'long long'
-    assert overloaded(np.array([1], dtype='complex')) == 'double complex'
-    assert overloaded(np.array([1], dtype='csingle')) == 'float complex'
+    assert m.overloaded(np.array([1], dtype='float64')) == 'double'
+    assert m.overloaded(np.array([1], dtype='float32')) == 'float'
+    assert m.overloaded(np.array([1], dtype='ushort')) == 'unsigned short'
+    assert m.overloaded(np.array([1], dtype='intc')) == 'int'
+    assert m.overloaded(np.array([1], dtype='longlong')) == 'long long'
+    assert m.overloaded(np.array([1], dtype='complex')) == 'double complex'
+    assert m.overloaded(np.array([1], dtype='csingle')) == 'float complex'
 
     # No exact match, should call first convertible version:
-    assert overloaded(np.array([1], dtype='uint8')) == 'double'
+    assert m.overloaded(np.array([1], dtype='uint8')) == 'double'
 
     with pytest.raises(TypeError) as excinfo:
-        overloaded("not an array")
+        m.overloaded("not an array")
     assert msg(excinfo.value) == """
         overloaded(): incompatible function arguments. The following argument types are supported:
             1. (arg0: numpy.ndarray[float64]) -> str
@@ -294,14 +269,14 @@ def test_overload_resolution(msg):
         Invoked with: 'not an array'
     """
 
-    assert overloaded2(np.array([1], dtype='float64')) == 'double'
-    assert overloaded2(np.array([1], dtype='float32')) == 'float'
-    assert overloaded2(np.array([1], dtype='complex64')) == 'float complex'
-    assert overloaded2(np.array([1], dtype='complex128')) == 'double complex'
-    assert overloaded2(np.array([1], dtype='float32')) == 'float'
+    assert m.overloaded2(np.array([1], dtype='float64')) == 'double'
+    assert m.overloaded2(np.array([1], dtype='float32')) == 'float'
+    assert m.overloaded2(np.array([1], dtype='complex64')) == 'float complex'
+    assert m.overloaded2(np.array([1], dtype='complex128')) == 'double complex'
+    assert m.overloaded2(np.array([1], dtype='float32')) == 'float'
 
-    assert overloaded3(np.array([1], dtype='float64')) == 'double'
-    assert overloaded3(np.array([1], dtype='intc')) == 'int'
+    assert m.overloaded3(np.array([1], dtype='float64')) == 'double'
+    assert m.overloaded3(np.array([1], dtype='intc')) == 'int'
     expected_exc = """
         overloaded3(): incompatible function arguments. The following argument types are supported:
             1. (arg0: numpy.ndarray[int32]) -> str
@@ -310,70 +285,118 @@ def test_overload_resolution(msg):
         Invoked with:"""
 
     with pytest.raises(TypeError) as excinfo:
-        overloaded3(np.array([1], dtype='uintc'))
+        m.overloaded3(np.array([1], dtype='uintc'))
     assert msg(excinfo.value) == expected_exc + " array([1], dtype=uint32)"
     with pytest.raises(TypeError) as excinfo:
-        overloaded3(np.array([1], dtype='float32'))
+        m.overloaded3(np.array([1], dtype='float32'))
     assert msg(excinfo.value) == expected_exc + " array([ 1.], dtype=float32)"
     with pytest.raises(TypeError) as excinfo:
-        overloaded3(np.array([1], dtype='complex'))
+        m.overloaded3(np.array([1], dtype='complex'))
     assert msg(excinfo.value) == expected_exc + " array([ 1.+0.j])"
 
     # Exact matches:
-    assert overloaded4(np.array([1], dtype='double')) == 'double'
-    assert overloaded4(np.array([1], dtype='longlong')) == 'long long'
+    assert m.overloaded4(np.array([1], dtype='double')) == 'double'
+    assert m.overloaded4(np.array([1], dtype='longlong')) == 'long long'
     # Non-exact matches requiring conversion.  Since float to integer isn't a
     # save conversion, it should go to the double overload, but short can go to
     # either (and so should end up on the first-registered, the long long).
-    assert overloaded4(np.array([1], dtype='float32')) == 'double'
-    assert overloaded4(np.array([1], dtype='short')) == 'long long'
+    assert m.overloaded4(np.array([1], dtype='float32')) == 'double'
+    assert m.overloaded4(np.array([1], dtype='short')) == 'long long'
 
-    assert overloaded5(np.array([1], dtype='double')) == 'double'
-    assert overloaded5(np.array([1], dtype='uintc')) == 'unsigned int'
-    assert overloaded5(np.array([1], dtype='float32')) == 'unsigned int'
+    assert m.overloaded5(np.array([1], dtype='double')) == 'double'
+    assert m.overloaded5(np.array([1], dtype='uintc')) == 'unsigned int'
+    assert m.overloaded5(np.array([1], dtype='float32')) == 'unsigned int'
 
 
-def test_greedy_string_overload():  # issue 685
-    from pybind11_tests.array import issue685
+def test_greedy_string_overload():
+    """Tests fix for #685 - ndarray shouldn't go to std::string overload"""
 
-    assert issue685("abc") == "string"
-    assert issue685(np.array([97, 98, 99], dtype='b')) == "array"
-    assert issue685(123) == "other"
+    assert m.issue685("abc") == "string"
+    assert m.issue685(np.array([97, 98, 99], dtype='b')) == "array"
+    assert m.issue685(123) == "other"
 
 
 def test_array_unchecked_fixed_dims(msg):
-    from pybind11_tests.array import (proxy_add2, proxy_init3F, proxy_init3, proxy_squared_L2_norm,
-                                      proxy_auxiliaries2, array_auxiliaries2)
-
     z1 = np.array([[1, 2], [3, 4]], dtype='float64')
-    proxy_add2(z1, 10)
+    m.proxy_add2(z1, 10)
     assert np.all(z1 == [[11, 12], [13, 14]])
 
     with pytest.raises(ValueError) as excinfo:
-        proxy_add2(np.array([1., 2, 3]), 5.0)
+        m.proxy_add2(np.array([1., 2, 3]), 5.0)
     assert msg(excinfo.value) == "array has incorrect number of dimensions: 1; expected 2"
 
     expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype='int')
-    assert np.all(proxy_init3(3.0) == expect_c)
+    assert np.all(m.proxy_init3(3.0) == expect_c)
     expect_f = np.transpose(expect_c)
-    assert np.all(proxy_init3F(3.0) == expect_f)
+    assert np.all(m.proxy_init3F(3.0) == expect_f)
 
-    assert proxy_squared_L2_norm(np.array(range(6))) == 55
-    assert proxy_squared_L2_norm(np.array(range(6), dtype="float64")) == 55
+    assert m.proxy_squared_L2_norm(np.array(range(6))) == 55
+    assert m.proxy_squared_L2_norm(np.array(range(6), dtype="float64")) == 55
 
-    assert proxy_auxiliaries2(z1) == [11, 11, True, 2, 8, 2, 2, 4, 32]
-    assert proxy_auxiliaries2(z1) == array_auxiliaries2(z1)
+    assert m.proxy_auxiliaries2(z1) == [11, 11, True, 2, 8, 2, 2, 4, 32]
+    assert m.proxy_auxiliaries2(z1) == m.array_auxiliaries2(z1)
 
 
 def test_array_unchecked_dyn_dims(msg):
-    from pybind11_tests.array import (proxy_add2_dyn, proxy_init3_dyn, proxy_auxiliaries2_dyn,
-                                      array_auxiliaries2)
     z1 = np.array([[1, 2], [3, 4]], dtype='float64')
-    proxy_add2_dyn(z1, 10)
+    m.proxy_add2_dyn(z1, 10)
     assert np.all(z1 == [[11, 12], [13, 14]])
 
     expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype='int')
-    assert np.all(proxy_init3_dyn(3.0) == expect_c)
+    assert np.all(m.proxy_init3_dyn(3.0) == expect_c)
+
+    assert m.proxy_auxiliaries2_dyn(z1) == [11, 11, True, 2, 8, 2, 2, 4, 32]
+    assert m.proxy_auxiliaries2_dyn(z1) == m.array_auxiliaries2(z1)
 
-    assert proxy_auxiliaries2_dyn(z1) == [11, 11, True, 2, 8, 2, 2, 4, 32]
-    assert proxy_auxiliaries2_dyn(z1) == array_auxiliaries2(z1)
+
+def test_array_failure():
+    with pytest.raises(ValueError) as excinfo:
+        m.array_fail_test()
+    assert str(excinfo.value) == 'cannot create a pybind11::array from a nullptr'
+
+    with pytest.raises(ValueError) as excinfo:
+        m.array_t_fail_test()
+    assert str(excinfo.value) == 'cannot create a pybind11::array_t from a nullptr'
+
+    with pytest.raises(ValueError) as excinfo:
+        m.array_fail_test_negative_size()
+    assert str(excinfo.value) == 'negative dimensions are not allowed'
+
+
+def test_initializer_list():
+    assert m.array_initializer_list1().shape == (1,)
+    assert m.array_initializer_list2().shape == (1, 2)
+    assert m.array_initializer_list3().shape == (1, 2, 3)
+    assert m.array_initializer_list4().shape == (1, 2, 3, 4)
+
+
+def test_array_resize(msg):
+    a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9], dtype='float64')
+    m.array_reshape2(a)
+    assert(a.size == 9)
+    assert(np.all(a == [[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
+
+    # total size change should succced with refcheck off
+    m.array_resize3(a, 4, False)
+    assert(a.size == 64)
+    # ... and fail with refcheck on
+    try:
+        m.array_resize3(a, 3, True)
+    except ValueError as e:
+        assert(str(e).startswith("cannot resize an array"))
+    # transposed array doesn't own data
+    b = a.transpose()
+    try:
+        m.array_resize3(b, 3, False)
+    except ValueError as e:
+        assert(str(e).startswith("cannot resize this array: it does not own its data"))
+    # ... but reshape should be fine
+    m.array_reshape2(b)
+    assert(b.shape == (8, 8))
+
+
+@pytest.unsupported_on_pypy
+def test_array_create_and_resize(msg):
+    a = m.create_and_resize(2)
+    assert(a.size == 4)
+    assert(np.all(a == 42.))
diff --git a/ext/pybind11/tests/test_numpy_dtypes.cpp b/ext/pybind11/tests/test_numpy_dtypes.cpp
index 1f6c85704..ddec851f6 100644
--- a/ext/pybind11/tests/test_numpy_dtypes.cpp
+++ b/ext/pybind11/tests/test_numpy_dtypes.cpp
@@ -70,6 +70,22 @@ struct StringStruct {
     std::array<char, 3> b;
 };
 
+struct ComplexStruct {
+    std::complex<float> cflt;
+    std::complex<double> cdbl;
+};
+
+std::ostream& operator<<(std::ostream& os, const ComplexStruct& v) {
+    return os << "c:" << v.cflt << "," << v.cdbl;
+}
+
+struct ArrayStruct {
+    char a[3][4];
+    int32_t b[2];
+    std::array<uint8_t, 3> c;
+    std::array<float, 2> d[4];
+};
+
 PYBIND11_PACKED(struct StructWithUglyNames {
     int8_t __x__;
     uint64_t __y__;
@@ -91,6 +107,27 @@ std::ostream& operator<<(std::ostream& os, const StringStruct& v) {
     return os << "'";
 }
 
+std::ostream& operator<<(std::ostream& os, const ArrayStruct& v) {
+    os << "a={";
+    for (int i = 0; i < 3; i++) {
+        if (i > 0)
+            os << ',';
+        os << '{';
+        for (int j = 0; j < 3; j++)
+            os << v.a[i][j] << ',';
+        os << v.a[i][3] << '}';
+    }
+    os << "},b={" << v.b[0] << ',' << v.b[1];
+    os << "},c={" << int(v.c[0]) << ',' << int(v.c[1]) << ',' << int(v.c[2]);
+    os << "},d={";
+    for (int i = 0; i < 4; i++) {
+        if (i > 0)
+            os << ',';
+        os << '{' << v.d[i][0] << ',' << v.d[i][1] << '}';
+    }
+    return os << '}';
+}
+
 std::ostream& operator<<(std::ostream& os, const EnumStruct& v) {
     return os << "e1=" << (v.e1 == E1::A ? "A" : "B") << ",e2=" << (v.e2 == E2::X ? "X" : "Y");
 }
@@ -119,66 +156,12 @@ py::array_t<S, 0> create_recarray(size_t n) {
     return arr;
 }
 
-std::string get_format_unbound() {
-    return py::format_descriptor<UnboundStruct>::format();
-}
-
-py::array_t<NestedStruct, 0> create_nested(size_t n) {
-    auto arr = mkarray_via_buffer<NestedStruct>(n);
-    auto req = arr.request();
-    auto ptr = static_cast<NestedStruct*>(req.ptr);
-    for (size_t i = 0; i < n; i++) {
-        SET_TEST_VALS(ptr[i].a, i);
-        SET_TEST_VALS(ptr[i].b, i + 1);
-    }
-    return arr;
-}
-
-py::array_t<PartialNestedStruct, 0> create_partial_nested(size_t n) {
-    auto arr = mkarray_via_buffer<PartialNestedStruct>(n);
-    auto req = arr.request();
-    auto ptr = static_cast<PartialNestedStruct*>(req.ptr);
-    for (size_t i = 0; i < n; i++) {
-        SET_TEST_VALS(ptr[i].a, i);
-    }
-    return arr;
-}
-
-py::array_t<StringStruct, 0> create_string_array(bool non_empty) {
-    auto arr = mkarray_via_buffer<StringStruct>(non_empty ? 4 : 0);
-    if (non_empty) {
-        auto req = arr.request();
-        auto ptr = static_cast<StringStruct*>(req.ptr);
-        for (size_t i = 0; i < req.size * req.itemsize; i++)
-            static_cast<char*>(req.ptr)[i] = 0;
-        ptr[1].a[0] = 'a'; ptr[1].b[0] = 'a';
-        ptr[2].a[0] = 'a'; ptr[2].b[0] = 'a';
-        ptr[3].a[0] = 'a'; ptr[3].b[0] = 'a';
-
-        ptr[2].a[1] = 'b'; ptr[2].b[1] = 'b';
-        ptr[3].a[1] = 'b'; ptr[3].b[1] = 'b';
-
-        ptr[3].a[2] = 'c'; ptr[3].b[2] = 'c';
-    }
-    return arr;
-}
-
-py::array_t<EnumStruct, 0> create_enum_array(size_t n) {
-    auto arr = mkarray_via_buffer<EnumStruct>(n);
-    auto ptr = (EnumStruct *) arr.mutable_data();
-    for (size_t i = 0; i < n; i++) {
-        ptr[i].e1 = static_cast<E1>(-1 + ((int) i % 2) * 2);
-        ptr[i].e2 = static_cast<E2>(1 + (i % 2));
-    }
-    return arr;
-}
-
 template <typename S>
 py::list print_recarray(py::array_t<S, 0> arr) {
     const auto req = arr.request();
     const auto ptr = static_cast<S*>(req.ptr);
     auto l = py::list();
-    for (size_t i = 0; i < req.size; i++) {
+    for (ssize_t i = 0; i < req.size; i++) {
         std::stringstream ss;
         ss << ptr[i];
         l.append(py::str(ss.str()));
@@ -186,47 +169,12 @@ py::list print_recarray(py::array_t<S, 0> arr) {
     return l;
 }
 
-py::list print_format_descriptors() {
-    const auto fmts = {
-        py::format_descriptor<SimpleStruct>::format(),
-        py::format_descriptor<PackedStruct>::format(),
-        py::format_descriptor<NestedStruct>::format(),
-        py::format_descriptor<PartialStruct>::format(),
-        py::format_descriptor<PartialNestedStruct>::format(),
-        py::format_descriptor<StringStruct>::format(),
-        py::format_descriptor<EnumStruct>::format()
-    };
-    auto l = py::list();
-    for (const auto &fmt : fmts) {
-        l.append(py::cast(fmt));
-    }
-    return l;
-}
-
-py::list print_dtypes() {
-    const auto dtypes = {
-        py::str(py::dtype::of<SimpleStruct>()),
-        py::str(py::dtype::of<PackedStruct>()),
-        py::str(py::dtype::of<NestedStruct>()),
-        py::str(py::dtype::of<PartialStruct>()),
-        py::str(py::dtype::of<PartialNestedStruct>()),
-        py::str(py::dtype::of<StringStruct>()),
-        py::str(py::dtype::of<EnumStruct>()),
-        py::str(py::dtype::of<StructWithUglyNames>())
-    };
-    auto l = py::list();
-    for (const auto &s : dtypes) {
-        l.append(s);
-    }
-    return l;
-}
-
 py::array_t<int32_t, 0> test_array_ctors(int i) {
     using arr_t = py::array_t<int32_t, 0>;
 
     std::vector<int32_t> data { 1, 2, 3, 4, 5, 6 };
-    std::vector<size_t> shape { 3, 2 };
-    std::vector<size_t> strides { 8, 4 };
+    std::vector<ssize_t> shape { 3, 2 };
+    std::vector<ssize_t> strides { 8, 4 };
 
     auto ptr = data.data();
     auto vptr = (void *) ptr;
@@ -296,51 +244,9 @@ py::list test_dtype_ctors() {
     return list;
 }
 
-struct TrailingPaddingStruct {
-    int32_t a;
-    char b;
-};
-
-py::dtype trailing_padding_dtype() {
-    return py::dtype::of<TrailingPaddingStruct>();
-}
-
-py::dtype buffer_to_dtype(py::buffer& buf) {
-    return py::dtype(buf.request());
-}
-
-py::list test_dtype_methods() {
-    py::list list;
-    auto dt1 = py::dtype::of<int32_t>();
-    auto dt2 = py::dtype::of<SimpleStruct>();
-    list.append(dt1); list.append(dt2);
-    list.append(py::bool_(dt1.has_fields())); list.append(py::bool_(dt2.has_fields()));
-    list.append(py::int_(dt1.itemsize())); list.append(py::int_(dt2.itemsize()));
-    return list;
-}
-
-struct CompareStruct {
-    bool x;
-    uint32_t y;
-    float z;
-};
-
-py::list test_compare_buffer_info() {
-    py::list list;
-    list.append(py::bool_(py::detail::compare_buffer_info<float>::compare(py::buffer_info(nullptr, sizeof(float), "f", 1))));
-    list.append(py::bool_(py::detail::compare_buffer_info<unsigned>::compare(py::buffer_info(nullptr, sizeof(int), "I", 1))));
-    list.append(py::bool_(py::detail::compare_buffer_info<long>::compare(py::buffer_info(nullptr, sizeof(long), "l", 1))));
-    list.append(py::bool_(py::detail::compare_buffer_info<long>::compare(py::buffer_info(nullptr, sizeof(long), sizeof(long) == sizeof(int) ? "i" : "q", 1))));
-    list.append(py::bool_(py::detail::compare_buffer_info<CompareStruct>::compare(py::buffer_info(nullptr, sizeof(CompareStruct), "T{?:x:3xI:y:f:z:}", 1))));
-    return list;
-}
-
-test_initializer numpy_dtypes([](py::module &m) {
-    try {
-        py::module::import("numpy");
-    } catch (...) {
-        return;
-    }
+TEST_SUBMODULE(numpy_dtypes, m) {
+    try { py::module::import("numpy"); }
+    catch (...) { return; }
 
     // typeinfo may be registered before the dtype descriptor for scalar casts to work...
     py::class_<SimpleStruct>(m, "SimpleStruct");
@@ -351,9 +257,9 @@ test_initializer numpy_dtypes([](py::module &m) {
     PYBIND11_NUMPY_DTYPE(PartialStruct, bool_, uint_, float_, ldbl_);
     PYBIND11_NUMPY_DTYPE(PartialNestedStruct, a);
     PYBIND11_NUMPY_DTYPE(StringStruct, a, b);
+    PYBIND11_NUMPY_DTYPE(ArrayStruct, a, b, c, d);
     PYBIND11_NUMPY_DTYPE(EnumStruct, e1, e2);
-    PYBIND11_NUMPY_DTYPE(TrailingPaddingStruct, a, b);
-    PYBIND11_NUMPY_DTYPE(CompareStruct, x, y, z);
+    PYBIND11_NUMPY_DTYPE(ComplexStruct, cflt, cdbl);
 
     // ... or after
     py::class_<PackedStruct>(m, "PackedStruct");
@@ -365,31 +271,181 @@ test_initializer numpy_dtypes([](py::module &m) {
 //    struct NotPOD { std::string v; NotPOD() : v("hi") {}; };
 //    PYBIND11_NUMPY_DTYPE(NotPOD, v);
 
+    // test_recarray, test_scalar_conversion
     m.def("create_rec_simple", &create_recarray<SimpleStruct>);
     m.def("create_rec_packed", &create_recarray<PackedStruct>);
-    m.def("create_rec_nested", &create_nested);
+    m.def("create_rec_nested", [](size_t n) { // test_signature
+        py::array_t<NestedStruct, 0> arr = mkarray_via_buffer<NestedStruct>(n);
+        auto req = arr.request();
+        auto ptr = static_cast<NestedStruct*>(req.ptr);
+        for (size_t i = 0; i < n; i++) {
+            SET_TEST_VALS(ptr[i].a, i);
+            SET_TEST_VALS(ptr[i].b, i + 1);
+        }
+        return arr;
+    });
     m.def("create_rec_partial", &create_recarray<PartialStruct>);
-    m.def("create_rec_partial_nested", &create_partial_nested);
-    m.def("print_format_descriptors", &print_format_descriptors);
+    m.def("create_rec_partial_nested", [](size_t n) {
+        py::array_t<PartialNestedStruct, 0> arr = mkarray_via_buffer<PartialNestedStruct>(n);
+        auto req = arr.request();
+        auto ptr = static_cast<PartialNestedStruct*>(req.ptr);
+        for (size_t i = 0; i < n; i++) {
+            SET_TEST_VALS(ptr[i].a, i);
+        }
+        return arr;
+    });
     m.def("print_rec_simple", &print_recarray<SimpleStruct>);
     m.def("print_rec_packed", &print_recarray<PackedStruct>);
     m.def("print_rec_nested", &print_recarray<NestedStruct>);
-    m.def("print_dtypes", &print_dtypes);
-    m.def("get_format_unbound", &get_format_unbound);
-    m.def("create_string_array", &create_string_array);
+
+    // test_format_descriptors
+    m.def("get_format_unbound", []() { return py::format_descriptor<UnboundStruct>::format(); });
+    m.def("print_format_descriptors", []() {
+        py::list l;
+        for (const auto &fmt : {
+            py::format_descriptor<SimpleStruct>::format(),
+            py::format_descriptor<PackedStruct>::format(),
+            py::format_descriptor<NestedStruct>::format(),
+            py::format_descriptor<PartialStruct>::format(),
+            py::format_descriptor<PartialNestedStruct>::format(),
+            py::format_descriptor<StringStruct>::format(),
+            py::format_descriptor<ArrayStruct>::format(),
+            py::format_descriptor<EnumStruct>::format(),
+            py::format_descriptor<ComplexStruct>::format()
+        }) {
+            l.append(py::cast(fmt));
+        }
+        return l;
+    });
+
+    // test_dtype
+    m.def("print_dtypes", []() {
+        py::list l;
+        for (const py::handle &d : {
+            py::dtype::of<SimpleStruct>(),
+            py::dtype::of<PackedStruct>(),
+            py::dtype::of<NestedStruct>(),
+            py::dtype::of<PartialStruct>(),
+            py::dtype::of<PartialNestedStruct>(),
+            py::dtype::of<StringStruct>(),
+            py::dtype::of<ArrayStruct>(),
+            py::dtype::of<EnumStruct>(),
+            py::dtype::of<StructWithUglyNames>(),
+            py::dtype::of<ComplexStruct>()
+        })
+            l.append(py::str(d));
+        return l;
+    });
+    m.def("test_dtype_ctors", &test_dtype_ctors);
+    m.def("test_dtype_methods", []() {
+        py::list list;
+        auto dt1 = py::dtype::of<int32_t>();
+        auto dt2 = py::dtype::of<SimpleStruct>();
+        list.append(dt1); list.append(dt2);
+        list.append(py::bool_(dt1.has_fields())); list.append(py::bool_(dt2.has_fields()));
+        list.append(py::int_(dt1.itemsize())); list.append(py::int_(dt2.itemsize()));
+        return list;
+    });
+    struct TrailingPaddingStruct {
+        int32_t a;
+        char b;
+    };
+    PYBIND11_NUMPY_DTYPE(TrailingPaddingStruct, a, b);
+    m.def("trailing_padding_dtype", []() { return py::dtype::of<TrailingPaddingStruct>(); });
+
+    // test_string_array
+    m.def("create_string_array", [](bool non_empty) {
+        py::array_t<StringStruct, 0> arr = mkarray_via_buffer<StringStruct>(non_empty ? 4 : 0);
+        if (non_empty) {
+            auto req = arr.request();
+            auto ptr = static_cast<StringStruct*>(req.ptr);
+            for (ssize_t i = 0; i < req.size * req.itemsize; i++)
+                static_cast<char*>(req.ptr)[i] = 0;
+            ptr[1].a[0] = 'a'; ptr[1].b[0] = 'a';
+            ptr[2].a[0] = 'a'; ptr[2].b[0] = 'a';
+            ptr[3].a[0] = 'a'; ptr[3].b[0] = 'a';
+
+            ptr[2].a[1] = 'b'; ptr[2].b[1] = 'b';
+            ptr[3].a[1] = 'b'; ptr[3].b[1] = 'b';
+
+            ptr[3].a[2] = 'c'; ptr[3].b[2] = 'c';
+        }
+        return arr;
+    });
     m.def("print_string_array", &print_recarray<StringStruct>);
-    m.def("create_enum_array", &create_enum_array);
+
+    // test_array_array
+    m.def("create_array_array", [](size_t n) {
+        py::array_t<ArrayStruct, 0> arr = mkarray_via_buffer<ArrayStruct>(n);
+        auto ptr = (ArrayStruct *) arr.mutable_data();
+        for (size_t i = 0; i < n; i++) {
+            for (size_t j = 0; j < 3; j++)
+                for (size_t k = 0; k < 4; k++)
+                    ptr[i].a[j][k] = char('A' + (i * 100 + j * 10 + k) % 26);
+            for (size_t j = 0; j < 2; j++)
+                ptr[i].b[j] = int32_t(i * 1000 + j);
+            for (size_t j = 0; j < 3; j++)
+                ptr[i].c[j] = uint8_t(i * 10 + j);
+            for (size_t j = 0; j < 4; j++)
+                for (size_t k = 0; k < 2; k++)
+                    ptr[i].d[j][k] = float(i) * 100.0f + float(j) * 10.0f + float(k);
+        }
+        return arr;
+    });
+    m.def("print_array_array", &print_recarray<ArrayStruct>);
+
+    // test_enum_array
+    m.def("create_enum_array", [](size_t n) {
+        py::array_t<EnumStruct, 0> arr = mkarray_via_buffer<EnumStruct>(n);
+        auto ptr = (EnumStruct *) arr.mutable_data();
+        for (size_t i = 0; i < n; i++) {
+            ptr[i].e1 = static_cast<E1>(-1 + ((int) i % 2) * 2);
+            ptr[i].e2 = static_cast<E2>(1 + (i % 2));
+        }
+        return arr;
+    });
     m.def("print_enum_array", &print_recarray<EnumStruct>);
+
+    // test_complex_array
+    m.def("create_complex_array", [](size_t n) {
+        py::array_t<ComplexStruct, 0> arr = mkarray_via_buffer<ComplexStruct>(n);
+        auto ptr = (ComplexStruct *) arr.mutable_data();
+        for (size_t i = 0; i < n; i++) {
+            ptr[i].cflt.real(float(i));
+            ptr[i].cflt.imag(float(i) + 0.25f);
+            ptr[i].cdbl.real(double(i) + 0.5);
+            ptr[i].cdbl.imag(double(i) + 0.75);
+        }
+        return arr;
+    });
+    m.def("print_complex_array", &print_recarray<ComplexStruct>);
+
+    // test_array_constructors
     m.def("test_array_ctors", &test_array_ctors);
-    m.def("test_dtype_ctors", &test_dtype_ctors);
-    m.def("test_dtype_methods", &test_dtype_methods);
-    m.def("compare_buffer_info", &test_compare_buffer_info);
-    m.def("trailing_padding_dtype", &trailing_padding_dtype);
-    m.def("buffer_to_dtype", &buffer_to_dtype);
+
+    // test_compare_buffer_info
+    struct CompareStruct {
+        bool x;
+        uint32_t y;
+        float z;
+    };
+    PYBIND11_NUMPY_DTYPE(CompareStruct, x, y, z);
+    m.def("compare_buffer_info", []() {
+        py::list list;
+        list.append(py::bool_(py::detail::compare_buffer_info<float>::compare(py::buffer_info(nullptr, sizeof(float), "f", 1))));
+        list.append(py::bool_(py::detail::compare_buffer_info<unsigned>::compare(py::buffer_info(nullptr, sizeof(int), "I", 1))));
+        list.append(py::bool_(py::detail::compare_buffer_info<long>::compare(py::buffer_info(nullptr, sizeof(long), "l", 1))));
+        list.append(py::bool_(py::detail::compare_buffer_info<long>::compare(py::buffer_info(nullptr, sizeof(long), sizeof(long) == sizeof(int) ? "i" : "q", 1))));
+        list.append(py::bool_(py::detail::compare_buffer_info<CompareStruct>::compare(py::buffer_info(nullptr, sizeof(CompareStruct), "T{?:x:3xI:y:f:z:}", 1))));
+        return list;
+    });
+    m.def("buffer_to_dtype", [](py::buffer& buf) { return py::dtype(buf.request()); });
+
+    // test_scalar_conversion
     m.def("f_simple", [](SimpleStruct s) { return s.uint_ * 10; });
     m.def("f_packed", [](PackedStruct s) { return s.uint_ * 10; });
     m.def("f_nested", [](NestedStruct s) { return s.a.uint_ * 10; });
-    m.def("register_dtype", []() { PYBIND11_NUMPY_DTYPE(SimpleStruct, bool_, uint_, float_, ldbl_); });
-});
 
-#undef PYBIND11_PACKED
+    // test_register_dtype
+    m.def("register_dtype", []() { PYBIND11_NUMPY_DTYPE(SimpleStruct, bool_, uint_, float_, ldbl_); });
+}
diff --git a/ext/pybind11/tests/test_numpy_dtypes.py b/ext/pybind11/tests/test_numpy_dtypes.py
index f63814f9d..5f9a95404 100644
--- a/ext/pybind11/tests/test_numpy_dtypes.py
+++ b/ext/pybind11/tests/test_numpy_dtypes.py
@@ -1,5 +1,6 @@
 import re
 import pytest
+from pybind11_tests import numpy_dtypes as m
 
 pytestmark = pytest.requires_numpy
 
@@ -65,68 +66,66 @@ def assert_equal(actual, expected_data, expected_dtype):
 
 
 def test_format_descriptors():
-    from pybind11_tests import get_format_unbound, print_format_descriptors
-
     with pytest.raises(RuntimeError) as excinfo:
-        get_format_unbound()
+        m.get_format_unbound()
     assert re.match('^NumPy type info missing for .*UnboundStruct.*$', str(excinfo.value))
 
     ld = np.dtype('longdouble')
     ldbl_fmt = ('4x' if ld.alignment > 4 else '') + ld.char
-    ss_fmt = "T{?:bool_:3xI:uint_:f:float_:" + ldbl_fmt + ":ldbl_:}"
+    ss_fmt = "^T{?:bool_:3xI:uint_:f:float_:" + ldbl_fmt + ":ldbl_:}"
     dbl = np.dtype('double')
-    partial_fmt = ("T{?:bool_:3xI:uint_:f:float_:" +
+    partial_fmt = ("^T{?:bool_:3xI:uint_:f:float_:" +
                    str(4 * (dbl.alignment > 4) + dbl.itemsize + 8 * (ld.alignment > 8)) +
                    "xg:ldbl_:}")
     nested_extra = str(max(8, ld.alignment))
-    assert print_format_descriptors() == [
+    assert m.print_format_descriptors() == [
         ss_fmt,
-        "T{?:bool_:^I:uint_:^f:float_:^g:ldbl_:}",
-        "T{" + ss_fmt + ":a:T{?:bool_:^I:uint_:^f:float_:^g:ldbl_:}:b:}",
+        "^T{?:bool_:I:uint_:f:float_:g:ldbl_:}",
+        "^T{" + ss_fmt + ":a:^T{?:bool_:I:uint_:f:float_:g:ldbl_:}:b:}",
         partial_fmt,
-        "T{" + nested_extra + "x" + partial_fmt + ":a:" + nested_extra + "x}",
-        "T{3s:a:3s:b:}",
-        'T{q:e1:B:e2:}'
+        "^T{" + nested_extra + "x" + partial_fmt + ":a:" + nested_extra + "x}",
+        "^T{3s:a:3s:b:}",
+        "^T{(3)4s:a:(2)i:b:(3)B:c:1x(4, 2)f:d:}",
+        '^T{q:e1:B:e2:}',
+        '^T{Zf:cflt:Zd:cdbl:}'
     ]
 
 
 def test_dtype(simple_dtype):
-    from pybind11_tests import (print_dtypes, test_dtype_ctors, test_dtype_methods,
-                                trailing_padding_dtype, buffer_to_dtype)
     from sys import byteorder
     e = '<' if byteorder == 'little' else '>'
 
-    assert print_dtypes() == [
+    assert m.print_dtypes() == [
         simple_dtype_fmt(),
         packed_dtype_fmt(),
         "[('a', {}), ('b', {})]".format(simple_dtype_fmt(), packed_dtype_fmt()),
         partial_dtype_fmt(),
         partial_nested_fmt(),
         "[('a', 'S3'), ('b', 'S3')]",
+        ("{{'names':['a','b','c','d'], " +
+         "'formats':[('S4', (3,)),('<i4', (2,)),('u1', (3,)),('<f4', (4, 2))], " +
+         "'offsets':[0,12,20,24], 'itemsize':56}}").format(e=e),
         "[('e1', '" + e + "i8'), ('e2', 'u1')]",
-        "[('x', 'i1'), ('y', '" + e + "u8')]"
+        "[('x', 'i1'), ('y', '" + e + "u8')]",
+        "[('cflt', '" + e + "c8'), ('cdbl', '" + e + "c16')]"
     ]
 
     d1 = np.dtype({'names': ['a', 'b'], 'formats': ['int32', 'float64'],
                    'offsets': [1, 10], 'itemsize': 20})
     d2 = np.dtype([('a', 'i4'), ('b', 'f4')])
-    assert test_dtype_ctors() == [np.dtype('int32'), np.dtype('float64'),
-                                  np.dtype('bool'), d1, d1, np.dtype('uint32'), d2]
+    assert m.test_dtype_ctors() == [np.dtype('int32'), np.dtype('float64'),
+                                    np.dtype('bool'), d1, d1, np.dtype('uint32'), d2]
 
-    assert test_dtype_methods() == [np.dtype('int32'), simple_dtype, False, True,
-                                    np.dtype('int32').itemsize, simple_dtype.itemsize]
+    assert m.test_dtype_methods() == [np.dtype('int32'), simple_dtype, False, True,
+                                      np.dtype('int32').itemsize, simple_dtype.itemsize]
 
-    assert trailing_padding_dtype() == buffer_to_dtype(np.zeros(1, trailing_padding_dtype()))
+    assert m.trailing_padding_dtype() == m.buffer_to_dtype(np.zeros(1, m.trailing_padding_dtype()))
 
 
 def test_recarray(simple_dtype, packed_dtype):
-    from pybind11_tests import (create_rec_simple, create_rec_packed, create_rec_nested,
-                                print_rec_simple, print_rec_packed, print_rec_nested,
-                                create_rec_partial, create_rec_partial_nested)
-
     elements = [(False, 0, 0.0, -0.0), (True, 1, 1.5, -2.5), (False, 2, 3.0, -5.0)]
 
-    for func, dtype in [(create_rec_simple, simple_dtype), (create_rec_packed, packed_dtype)]:
+    for func, dtype in [(m.create_rec_simple, simple_dtype), (m.create_rec_packed, packed_dtype)]:
         arr = func(0)
         assert arr.dtype == dtype
         assert_equal(arr, [], simple_dtype)
@@ -138,13 +137,13 @@ def test_recarray(simple_dtype, packed_dtype):
         assert_equal(arr, elements, packed_dtype)
 
         if dtype == simple_dtype:
-            assert print_rec_simple(arr) == [
+            assert m.print_rec_simple(arr) == [
                 "s:0,0,0,-0",
                 "s:1,1,1.5,-2.5",
                 "s:0,2,3,-5"
             ]
         else:
-            assert print_rec_packed(arr) == [
+            assert m.print_rec_packed(arr) == [
                 "p:0,0,0,-0",
                 "p:1,1,1.5,-2.5",
                 "p:0,2,3,-5"
@@ -152,22 +151,22 @@ def test_recarray(simple_dtype, packed_dtype):
 
     nested_dtype = np.dtype([('a', simple_dtype), ('b', packed_dtype)])
 
-    arr = create_rec_nested(0)
+    arr = m.create_rec_nested(0)
     assert arr.dtype == nested_dtype
     assert_equal(arr, [], nested_dtype)
 
-    arr = create_rec_nested(3)
+    arr = m.create_rec_nested(3)
     assert arr.dtype == nested_dtype
     assert_equal(arr, [((False, 0, 0.0, -0.0), (True, 1, 1.5, -2.5)),
                        ((True, 1, 1.5, -2.5), (False, 2, 3.0, -5.0)),
                        ((False, 2, 3.0, -5.0), (True, 3, 4.5, -7.5))], nested_dtype)
-    assert print_rec_nested(arr) == [
+    assert m.print_rec_nested(arr) == [
         "n:a=s:0,0,0,-0;b=p:1,1,1.5,-2.5",
         "n:a=s:1,1,1.5,-2.5;b=p:0,2,3,-5",
         "n:a=s:0,2,3,-5;b=p:1,3,4.5,-7.5"
     ]
 
-    arr = create_rec_partial(3)
+    arr = m.create_rec_partial(3)
     assert str(arr.dtype) == partial_dtype_fmt()
     partial_dtype = arr.dtype
     assert '' not in arr.dtype.fields
@@ -175,32 +174,28 @@ def test_recarray(simple_dtype, packed_dtype):
     assert_equal(arr, elements, simple_dtype)
     assert_equal(arr, elements, packed_dtype)
 
-    arr = create_rec_partial_nested(3)
+    arr = m.create_rec_partial_nested(3)
     assert str(arr.dtype) == partial_nested_fmt()
     assert '' not in arr.dtype.fields
     assert '' not in arr.dtype.fields['a'][0].fields
     assert arr.dtype.itemsize > partial_dtype.itemsize
-    np.testing.assert_equal(arr['a'], create_rec_partial(3))
+    np.testing.assert_equal(arr['a'], m.create_rec_partial(3))
 
 
 def test_array_constructors():
-    from pybind11_tests import test_array_ctors
-
     data = np.arange(1, 7, dtype='int32')
     for i in range(8):
-        np.testing.assert_array_equal(test_array_ctors(10 + i), data.reshape((3, 2)))
-        np.testing.assert_array_equal(test_array_ctors(20 + i), data.reshape((3, 2)))
+        np.testing.assert_array_equal(m.test_array_ctors(10 + i), data.reshape((3, 2)))
+        np.testing.assert_array_equal(m.test_array_ctors(20 + i), data.reshape((3, 2)))
     for i in range(5):
-        np.testing.assert_array_equal(test_array_ctors(30 + i), data)
-        np.testing.assert_array_equal(test_array_ctors(40 + i), data)
+        np.testing.assert_array_equal(m.test_array_ctors(30 + i), data)
+        np.testing.assert_array_equal(m.test_array_ctors(40 + i), data)
 
 
 def test_string_array():
-    from pybind11_tests import create_string_array, print_string_array
-
-    arr = create_string_array(True)
+    arr = m.create_string_array(True)
     assert str(arr.dtype) == "[('a', 'S3'), ('b', 'S3')]"
-    assert print_string_array(arr) == [
+    assert m.print_string_array(arr) == [
         "a='',b=''",
         "a='a',b='a'",
         "a='ab',b='ab'",
@@ -209,44 +204,78 @@ def test_string_array():
     dtype = arr.dtype
     assert arr['a'].tolist() == [b'', b'a', b'ab', b'abc']
     assert arr['b'].tolist() == [b'', b'a', b'ab', b'abc']
-    arr = create_string_array(False)
+    arr = m.create_string_array(False)
     assert dtype == arr.dtype
 
 
+def test_array_array():
+    from sys import byteorder
+    e = '<' if byteorder == 'little' else '>'
+
+    arr = m.create_array_array(3)
+    assert str(arr.dtype) == (
+        "{{'names':['a','b','c','d'], " +
+        "'formats':[('S4', (3,)),('<i4', (2,)),('u1', (3,)),('{e}f4', (4, 2))], " +
+        "'offsets':[0,12,20,24], 'itemsize':56}}").format(e=e)
+    assert m.print_array_array(arr) == [
+        "a={{A,B,C,D},{K,L,M,N},{U,V,W,X}},b={0,1}," +
+        "c={0,1,2},d={{0,1},{10,11},{20,21},{30,31}}",
+        "a={{W,X,Y,Z},{G,H,I,J},{Q,R,S,T}},b={1000,1001}," +
+        "c={10,11,12},d={{100,101},{110,111},{120,121},{130,131}}",
+        "a={{S,T,U,V},{C,D,E,F},{M,N,O,P}},b={2000,2001}," +
+        "c={20,21,22},d={{200,201},{210,211},{220,221},{230,231}}",
+    ]
+    assert arr['a'].tolist() == [[b'ABCD', b'KLMN', b'UVWX'],
+                                 [b'WXYZ', b'GHIJ', b'QRST'],
+                                 [b'STUV', b'CDEF', b'MNOP']]
+    assert arr['b'].tolist() == [[0, 1], [1000, 1001], [2000, 2001]]
+    assert m.create_array_array(0).dtype == arr.dtype
+
+
 def test_enum_array():
-    from pybind11_tests import create_enum_array, print_enum_array
     from sys import byteorder
     e = '<' if byteorder == 'little' else '>'
 
-    arr = create_enum_array(3)
+    arr = m.create_enum_array(3)
     dtype = arr.dtype
     assert dtype == np.dtype([('e1', e + 'i8'), ('e2', 'u1')])
-    assert print_enum_array(arr) == [
+    assert m.print_enum_array(arr) == [
         "e1=A,e2=X",
         "e1=B,e2=Y",
         "e1=A,e2=X"
     ]
     assert arr['e1'].tolist() == [-1, 1, -1]
     assert arr['e2'].tolist() == [1, 2, 1]
-    assert create_enum_array(0).dtype == dtype
+    assert m.create_enum_array(0).dtype == dtype
 
 
-def test_signature(doc):
-    from pybind11_tests import create_rec_nested
+def test_complex_array():
+    from sys import byteorder
+    e = '<' if byteorder == 'little' else '>'
+
+    arr = m.create_complex_array(3)
+    dtype = arr.dtype
+    assert dtype == np.dtype([('cflt', e + 'c8'), ('cdbl', e + 'c16')])
+    assert m.print_complex_array(arr) == [
+        "c:(0,0.25),(0.5,0.75)",
+        "c:(1,1.25),(1.5,1.75)",
+        "c:(2,2.25),(2.5,2.75)"
+    ]
+    assert arr['cflt'].tolist() == [0.0 + 0.25j, 1.0 + 1.25j, 2.0 + 2.25j]
+    assert arr['cdbl'].tolist() == [0.5 + 0.75j, 1.5 + 1.75j, 2.5 + 2.75j]
+    assert m.create_complex_array(0).dtype == dtype
 
-    assert doc(create_rec_nested) == "create_rec_nested(arg0: int) -> numpy.ndarray[NestedStruct]"
 
+def test_signature(doc):
+    assert doc(m.create_rec_nested) == \
+        "create_rec_nested(arg0: int) -> numpy.ndarray[NestedStruct]"
 
-def test_scalar_conversion():
-    from pybind11_tests import (create_rec_simple, f_simple,
-                                create_rec_packed, f_packed,
-                                create_rec_nested, f_nested,
-                                create_enum_array)
 
+def test_scalar_conversion():
     n = 3
-    arrays = [create_rec_simple(n), create_rec_packed(n),
-              create_rec_nested(n), create_enum_array(n)]
-    funcs = [f_simple, f_packed, f_nested]
+    arrays = [m.create_rec_simple(n), m.create_rec_packed(n),
+              m.create_rec_nested(n), m.create_enum_array(n)]
+    funcs = [m.f_simple, m.f_packed, m.f_nested]
 
     for i, func in enumerate(funcs):
         for j, arr in enumerate(arrays):
@@ -259,14 +288,11 @@ def test_scalar_conversion():
 
 
 def test_register_dtype():
-    from pybind11_tests import register_dtype
-
     with pytest.raises(RuntimeError) as excinfo:
-        register_dtype()
+        m.register_dtype()
     assert 'dtype is already registered' in str(excinfo.value)
 
 
 @pytest.requires_numpy
 def test_compare_buffer_info():
-    from pybind11_tests import compare_buffer_info
-    assert all(compare_buffer_info())
+    assert all(m.compare_buffer_info())
diff --git a/ext/pybind11/tests/test_numpy_vectorize.cpp b/ext/pybind11/tests/test_numpy_vectorize.cpp
index 8e951c6e1..a875a74b9 100644
--- a/ext/pybind11/tests/test_numpy_vectorize.cpp
+++ b/ext/pybind11/tests/test_numpy_vectorize.cpp
@@ -16,11 +16,11 @@ double my_func(int x, float y, double z) {
     return (float) x*y*z;
 }
 
-std::complex<double> my_func3(std::complex<double> c) {
-    return c * std::complex<double>(2.f);
-}
+TEST_SUBMODULE(numpy_vectorize, m) {
+    try { py::module::import("numpy"); }
+    catch (...) { return; }
 
-test_initializer numpy_vectorize([](py::module &m) {
+    // test_vectorize, test_docs, test_array_collapse
     // Vectorize all arguments of a function (though non-vector arguments are also allowed)
     m.def("vectorized_func", py::vectorize(my_func));
 
@@ -32,14 +32,45 @@ test_initializer numpy_vectorize([](py::module &m) {
     );
 
     // Vectorize a complex-valued function
-    m.def("vectorized_func3", py::vectorize(my_func3));
+    m.def("vectorized_func3", py::vectorize(
+        [](std::complex<double> c) { return c * std::complex<double>(2.f); }
+    ));
 
-    /// Numpy function which only accepts specific data types
+    // test_type_selection
+    // Numpy function which only accepts specific data types
     m.def("selective_func", [](py::array_t<int, py::array::c_style>) { return "Int branch taken."; });
     m.def("selective_func", [](py::array_t<float, py::array::c_style>) { return "Float branch taken."; });
     m.def("selective_func", [](py::array_t<std::complex<float>, py::array::c_style>) { return "Complex float branch taken."; });
 
 
+    // test_passthrough_arguments
+    // Passthrough test: references and non-pod types should be automatically passed through (in the
+    // function definition below, only `b`, `d`, and `g` are vectorized):
+    struct NonPODClass {
+        NonPODClass(int v) : value{v} {}
+        int value;
+    };
+    py::class_<NonPODClass>(m, "NonPODClass").def(py::init<int>());
+    m.def("vec_passthrough", py::vectorize(
+        [](double *a, double b, py::array_t<double> c, const int &d, int &e, NonPODClass f, const double g) {
+            return *a + b + c.at(0) + d + e + f.value + g;
+        }
+    ));
+
+    // test_method_vectorization
+    struct VectorizeTestClass {
+        VectorizeTestClass(int v) : value{v} {};
+        float method(int x, float y) { return y + (float) (x + value); }
+        int value = 0;
+    };
+    py::class_<VectorizeTestClass> vtc(m, "VectorizeTestClass");
+    vtc .def(py::init<int>())
+        .def_readwrite("value", &VectorizeTestClass::value);
+
+    // Automatic vectorizing of methods
+    vtc.def("method", py::vectorize(&VectorizeTestClass::method));
+
+    // test_trivial_broadcasting
     // Internal optimization test for whether the input is trivially broadcastable:
     py::enum_<py::detail::broadcast_trivial>(m, "trivial")
         .value("f_trivial", py::detail::broadcast_trivial::f_trivial)
@@ -50,9 +81,9 @@ test_initializer numpy_vectorize([](py::module &m) {
                 py::array_t<float, py::array::forcecast> arg2,
                 py::array_t<double, py::array::forcecast> arg3
                 ) {
-        size_t ndim;
-        std::vector<size_t> shape;
+        ssize_t ndim;
+        std::vector<ssize_t> shape;
         std::array<py::buffer_info, 3> buffers {{ arg1.request(), arg2.request(), arg3.request() }};
         return py::detail::broadcast(buffers, ndim, shape);
     });
-});
+}
diff --git a/ext/pybind11/tests/test_numpy_vectorize.py b/ext/pybind11/tests/test_numpy_vectorize.py
index 7ae777227..0e9c88397 100644
--- a/ext/pybind11/tests/test_numpy_vectorize.py
+++ b/ext/pybind11/tests/test_numpy_vectorize.py
@@ -1,4 +1,5 @@
 import pytest
+from pybind11_tests import numpy_vectorize as m
 
 pytestmark = pytest.requires_numpy
 
@@ -7,11 +8,9 @@ with pytest.suppress(ImportError):
 
 
 def test_vectorize(capture):
-    from pybind11_tests import vectorized_func, vectorized_func2, vectorized_func3
+    assert np.isclose(m.vectorized_func3(np.array(3 + 7j)), [6 + 14j])
 
-    assert np.isclose(vectorized_func3(np.array(3 + 7j)), [6 + 14j])
-
-    for f in [vectorized_func, vectorized_func2]:
+    for f in [m.vectorized_func, m.vectorized_func2]:
         with capture:
             assert np.isclose(f(1, 2, 3), 6)
         assert capture == "my_func(x:int=1, y:float=2, z:float=3)"
@@ -103,23 +102,19 @@ def test_vectorize(capture):
 
 
 def test_type_selection():
-    from pybind11_tests import selective_func
-
-    assert selective_func(np.array([1], dtype=np.int32)) == "Int branch taken."
-    assert selective_func(np.array([1.0], dtype=np.float32)) == "Float branch taken."
-    assert selective_func(np.array([1.0j], dtype=np.complex64)) == "Complex float branch taken."
+    assert m.selective_func(np.array([1], dtype=np.int32)) == "Int branch taken."
+    assert m.selective_func(np.array([1.0], dtype=np.float32)) == "Float branch taken."
+    assert m.selective_func(np.array([1.0j], dtype=np.complex64)) == "Complex float branch taken."
 
 
 def test_docs(doc):
-    from pybind11_tests import vectorized_func
-
-    assert doc(vectorized_func) == """
+    assert doc(m.vectorized_func) == """
         vectorized_func(arg0: numpy.ndarray[int32], arg1: numpy.ndarray[float32], arg2: numpy.ndarray[float64]) -> object
     """  # noqa: E501 line too long
 
 
 def test_trivial_broadcasting():
-    from pybind11_tests import vectorized_is_trivial, trivial, vectorized_func
+    trivial, vectorized_is_trivial = m.trivial, m.vectorized_is_trivial
 
     assert vectorized_is_trivial(1, 2, 3) == trivial.c_trivial
     assert vectorized_is_trivial(np.array(1), np.array(2), 3) == trivial.c_trivial
@@ -153,9 +148,49 @@ def test_trivial_broadcasting():
     assert vectorized_is_trivial(z1[1::4, 1::4], y2, 1) == trivial.f_trivial
     assert vectorized_is_trivial(y1[1::4, 1::4], z2, 1) == trivial.c_trivial
 
-    assert vectorized_func(z1, z2, z3).flags.c_contiguous
-    assert vectorized_func(y1, y2, y3).flags.f_contiguous
-    assert vectorized_func(z1, 1, 1).flags.c_contiguous
-    assert vectorized_func(1, y2, 1).flags.f_contiguous
-    assert vectorized_func(z1[1::4, 1::4], y2, 1).flags.f_contiguous
-    assert vectorized_func(y1[1::4, 1::4], z2, 1).flags.c_contiguous
+    assert m.vectorized_func(z1, z2, z3).flags.c_contiguous
+    assert m.vectorized_func(y1, y2, y3).flags.f_contiguous
+    assert m.vectorized_func(z1, 1, 1).flags.c_contiguous
+    assert m.vectorized_func(1, y2, 1).flags.f_contiguous
+    assert m.vectorized_func(z1[1::4, 1::4], y2, 1).flags.f_contiguous
+    assert m.vectorized_func(y1[1::4, 1::4], z2, 1).flags.c_contiguous
+
+
+def test_passthrough_arguments(doc):
+    assert doc(m.vec_passthrough) == (
+        "vec_passthrough(" + ", ".join([
+            "arg0: float",
+            "arg1: numpy.ndarray[float64]",
+            "arg2: numpy.ndarray[float64]",
+            "arg3: numpy.ndarray[int32]",
+            "arg4: int",
+            "arg5: m.numpy_vectorize.NonPODClass",
+            "arg6: numpy.ndarray[float64]"]) + ") -> object")
+
+    b = np.array([[10, 20, 30]], dtype='float64')
+    c = np.array([100, 200])  # NOT a vectorized argument
+    d = np.array([[1000], [2000], [3000]], dtype='int')
+    g = np.array([[1000000, 2000000, 3000000]], dtype='int')  # requires casting
+    assert np.all(
+        m.vec_passthrough(1, b, c, d, 10000, m.NonPODClass(100000), g) ==
+        np.array([[1111111, 2111121, 3111131],
+                  [1112111, 2112121, 3112131],
+                  [1113111, 2113121, 3113131]]))
+
+
+def test_method_vectorization():
+    o = m.VectorizeTestClass(3)
+    x = np.array([1, 2], dtype='int')
+    y = np.array([[10], [20]], dtype='float32')
+    assert np.all(o.method(x, y) == [[14, 15], [24, 25]])
+
+
+def test_array_collapse():
+    assert not isinstance(m.vectorized_func(1, 2, 3), np.ndarray)
+    assert not isinstance(m.vectorized_func(np.array(1), 2, 3), np.ndarray)
+    z = m.vectorized_func([1], 2, 3)
+    assert isinstance(z, np.ndarray)
+    assert z.shape == (1, )
+    z = m.vectorized_func(1, [[[2]]], 3)
+    assert isinstance(z, np.ndarray)
+    assert z.shape == (1, 1, 1)
diff --git a/ext/pybind11/tests/test_opaque_types.cpp b/ext/pybind11/tests/test_opaque_types.cpp
index 54f4dc7a5..5e83df0f6 100644
--- a/ext/pybind11/tests/test_opaque_types.cpp
+++ b/ext/pybind11/tests/test_opaque_types.cpp
@@ -11,17 +11,13 @@
 #include <pybind11/stl.h>
 #include <vector>
 
-typedef std::vector<std::string> StringList;
-
-class ClassWithSTLVecProperty {
-public:
-    StringList stringList;
-};
+using StringList = std::vector<std::string>;
 
 /* IMPORTANT: Disable internal pybind11 translation mechanisms for STL data structures */
 PYBIND11_MAKE_OPAQUE(StringList);
 
-test_initializer opaque_types([](py::module &m) {
+TEST_SUBMODULE(opaque_types, m) {
+    // test_string_list
     py::class_<StringList>(m, "StringList")
         .def(py::init<>())
         .def("pop_back", &StringList::pop_back)
@@ -33,6 +29,10 @@ test_initializer opaque_types([](py::module &m) {
            return py::make_iterator(v.begin(), v.end());
         }, py::keep_alive<0, 1>());
 
+    class ClassWithSTLVecProperty {
+    public:
+        StringList stringList;
+    };
     py::class_<ClassWithSTLVecProperty>(m, "ClassWithSTLVecProperty")
         .def(py::init<>())
         .def_readwrite("stringList", &ClassWithSTLVecProperty::stringList);
@@ -49,6 +49,7 @@ test_initializer opaque_types([](py::module &m) {
         return ret + "]";
     });
 
+    // test_pointers
     m.def("return_void_ptr", []() { return (void *) 0x1234; });
     m.def("get_void_ptr_value", [](void *ptr) { return reinterpret_cast<std::intptr_t>(ptr); });
     m.def("return_null_str", []() { return (char *) nullptr; });
@@ -59,4 +60,4 @@ test_initializer opaque_types([](py::module &m) {
         result->push_back("some value");
         return std::unique_ptr<StringList>(result);
     });
-});
+}
diff --git a/ext/pybind11/tests/test_opaque_types.py b/ext/pybind11/tests/test_opaque_types.py
index 1cd410208..2d3aef5d1 100644
--- a/ext/pybind11/tests/test_opaque_types.py
+++ b/ext/pybind11/tests/test_opaque_types.py
@@ -1,40 +1,36 @@
 import pytest
+from pybind11_tests import opaque_types as m
+from pybind11_tests import ConstructorStats, UserType
 
 
 def test_string_list():
-    from pybind11_tests import StringList, ClassWithSTLVecProperty, print_opaque_list
-
-    l = StringList()
+    l = m.StringList()
     l.push_back("Element 1")
     l.push_back("Element 2")
-    assert print_opaque_list(l) == "Opaque list: [Element 1, Element 2]"
+    assert m.print_opaque_list(l) == "Opaque list: [Element 1, Element 2]"
     assert l.back() == "Element 2"
 
     for i, k in enumerate(l, start=1):
         assert k == "Element {}".format(i)
     l.pop_back()
-    assert print_opaque_list(l) == "Opaque list: [Element 1]"
+    assert m.print_opaque_list(l) == "Opaque list: [Element 1]"
 
-    cvp = ClassWithSTLVecProperty()
-    assert print_opaque_list(cvp.stringList) == "Opaque list: []"
+    cvp = m.ClassWithSTLVecProperty()
+    assert m.print_opaque_list(cvp.stringList) == "Opaque list: []"
 
     cvp.stringList = l
     cvp.stringList.push_back("Element 3")
-    assert print_opaque_list(cvp.stringList) == "Opaque list: [Element 1, Element 3]"
+    assert m.print_opaque_list(cvp.stringList) == "Opaque list: [Element 1, Element 3]"
 
 
 def test_pointers(msg):
-    from pybind11_tests import (return_void_ptr, get_void_ptr_value, ExampleMandA,
-                                print_opaque_list, return_null_str, get_null_str_value,
-                                return_unique_ptr, ConstructorStats)
-
-    living_before = ConstructorStats.get(ExampleMandA).alive()
-    assert get_void_ptr_value(return_void_ptr()) == 0x1234
-    assert get_void_ptr_value(ExampleMandA())  # Should also work for other C++ types
-    assert ConstructorStats.get(ExampleMandA).alive() == living_before
+    living_before = ConstructorStats.get(UserType).alive()
+    assert m.get_void_ptr_value(m.return_void_ptr()) == 0x1234
+    assert m.get_void_ptr_value(UserType())  # Should also work for other C++ types
+    assert ConstructorStats.get(UserType).alive() == living_before
 
     with pytest.raises(TypeError) as excinfo:
-        get_void_ptr_value([1, 2, 3])  # This should not work
+        m.get_void_ptr_value([1, 2, 3])  # This should not work
     assert msg(excinfo.value) == """
         get_void_ptr_value(): incompatible function arguments. The following argument types are supported:
             1. (arg0: capsule) -> int
@@ -42,9 +38,9 @@ def test_pointers(msg):
         Invoked with: [1, 2, 3]
     """  # noqa: E501 line too long
 
-    assert return_null_str() is None
-    assert get_null_str_value(return_null_str()) is not None
+    assert m.return_null_str() is None
+    assert m.get_null_str_value(m.return_null_str()) is not None
 
-    ptr = return_unique_ptr()
+    ptr = m.return_unique_ptr()
     assert "StringList" in repr(ptr)
-    assert print_opaque_list(ptr) == "Opaque list: [some value]"
+    assert m.print_opaque_list(ptr) == "Opaque list: [some value]"
diff --git a/ext/pybind11/tests/test_operator_overloading.cpp b/ext/pybind11/tests/test_operator_overloading.cpp
index 93aea8010..4ad34d104 100644
--- a/ext/pybind11/tests/test_operator_overloading.cpp
+++ b/ext/pybind11/tests/test_operator_overloading.cpp
@@ -10,28 +10,18 @@
 #include "pybind11_tests.h"
 #include "constructor_stats.h"
 #include <pybind11/operators.h>
+#include <functional>
 
 class Vector2 {
 public:
     Vector2(float x, float y) : x(x), y(y) { print_created(this, toString()); }
     Vector2(const Vector2 &v) : x(v.x), y(v.y) { print_copy_created(this); }
     Vector2(Vector2 &&v) : x(v.x), y(v.y) { print_move_created(this); v.x = v.y = 0; }
+    Vector2 &operator=(const Vector2 &v) { x = v.x; y = v.y; print_copy_assigned(this); return *this; }
+    Vector2 &operator=(Vector2 &&v) { x = v.x; y = v.y; v.x = v.y = 0; print_move_assigned(this); return *this; }
     ~Vector2() { print_destroyed(this); }
 
-    std::string toString() const {
-        return "[" + std::to_string(x) + ", " + std::to_string(y) + "]";
-    }
-
-    void operator=(const Vector2 &v) {
-        print_copy_assigned(this);
-        x = v.x;
-        y = v.y;
-    }
-
-    void operator=(Vector2 &&v) {
-        print_move_assigned(this);
-        x = v.x; y = v.y; v.x = v.y = 0;
-    }
+    std::string toString() const { return "[" + std::to_string(x) + ", " + std::to_string(y) + "]"; }
 
     Vector2 operator+(const Vector2 &v) const { return Vector2(x + v.x, y + v.y); }
     Vector2 operator-(const Vector2 &v) const { return Vector2(x - v.x, y - v.y); }
@@ -39,10 +29,14 @@ public:
     Vector2 operator+(float value) const { return Vector2(x + value, y + value); }
     Vector2 operator*(float value) const { return Vector2(x * value, y * value); }
     Vector2 operator/(float value) const { return Vector2(x / value, y / value); }
+    Vector2 operator*(const Vector2 &v) const { return Vector2(x * v.x, y * v.y); }
+    Vector2 operator/(const Vector2 &v) const { return Vector2(x / v.x, y / v.y); }
     Vector2& operator+=(const Vector2 &v) { x += v.x; y += v.y; return *this; }
     Vector2& operator-=(const Vector2 &v) { x -= v.x; y -= v.y; return *this; }
     Vector2& operator*=(float v) { x *= v; y *= v; return *this; }
     Vector2& operator/=(float v) { x /= v; y /= v; return *this; }
+    Vector2& operator*=(const Vector2 &v) { x *= v.x; y *= v.y; return *this; }
+    Vector2& operator/=(const Vector2 &v) { x /= v.x; y /= v.y; return *this; }
 
     friend Vector2 operator+(float f, const Vector2 &v) { return Vector2(f + v.x, f + v.y); }
     friend Vector2 operator-(float f, const Vector2 &v) { return Vector2(f - v.x, f - v.y); }
@@ -52,7 +46,25 @@ private:
     float x, y;
 };
 
-test_initializer operator_overloading([](py::module &m) {
+class C1 { };
+class C2 { };
+
+int operator+(const C1 &, const C1 &) { return 11; }
+int operator+(const C2 &, const C2 &) { return 22; }
+int operator+(const C2 &, const C1 &) { return 21; }
+int operator+(const C1 &, const C2 &) { return 12; }
+
+namespace std {
+    template<>
+    struct hash<Vector2> {
+        // Not a good hash function, but easy to test
+        size_t operator()(const Vector2 &) { return 4; }
+    };
+}
+
+TEST_SUBMODULE(operators, m) {
+
+    // test_operator_overloading
     py::class_<Vector2>(m, "Vector2")
         .def(py::init<float, float>())
         .def(py::self + py::self)
@@ -61,16 +73,74 @@ test_initializer operator_overloading([](py::module &m) {
         .def(py::self - float())
         .def(py::self * float())
         .def(py::self / float())
+        .def(py::self * py::self)
+        .def(py::self / py::self)
         .def(py::self += py::self)
         .def(py::self -= py::self)
         .def(py::self *= float())
         .def(py::self /= float())
+        .def(py::self *= py::self)
+        .def(py::self /= py::self)
         .def(float() + py::self)
         .def(float() - py::self)
         .def(float() * py::self)
         .def(float() / py::self)
         .def("__str__", &Vector2::toString)
+        .def(hash(py::self))
         ;
 
     m.attr("Vector") = m.attr("Vector2");
-});
+
+    // test_operators_notimplemented
+    // #393: need to return NotSupported to ensure correct arithmetic operator behavior
+    py::class_<C1>(m, "C1")
+        .def(py::init<>())
+        .def(py::self + py::self);
+
+    py::class_<C2>(m, "C2")
+        .def(py::init<>())
+        .def(py::self + py::self)
+        .def("__add__", [](const C2& c2, const C1& c1) { return c2 + c1; })
+        .def("__radd__", [](const C2& c2, const C1& c1) { return c1 + c2; });
+
+    // test_nested
+    // #328: first member in a class can't be used in operators
+    struct NestABase { int value = -2; };
+    py::class_<NestABase>(m, "NestABase")
+        .def(py::init<>())
+        .def_readwrite("value", &NestABase::value);
+
+    struct NestA : NestABase {
+        int value = 3;
+        NestA& operator+=(int i) { value += i; return *this; }
+    };
+    py::class_<NestA>(m, "NestA")
+        .def(py::init<>())
+        .def(py::self += int())
+        .def("as_base", [](NestA &a) -> NestABase& {
+            return (NestABase&) a;
+        }, py::return_value_policy::reference_internal);
+    m.def("get_NestA", [](const NestA &a) { return a.value; });
+
+    struct NestB {
+        NestA a;
+        int value = 4;
+        NestB& operator-=(int i) { value -= i; return *this; }
+    };
+    py::class_<NestB>(m, "NestB")
+        .def(py::init<>())
+        .def(py::self -= int())
+        .def_readwrite("a", &NestB::a);
+    m.def("get_NestB", [](const NestB &b) { return b.value; });
+
+    struct NestC {
+        NestB b;
+        int value = 5;
+        NestC& operator*=(int i) { value *= i; return *this; }
+    };
+    py::class_<NestC>(m, "NestC")
+        .def(py::init<>())
+        .def(py::self *= int())
+        .def_readwrite("b", &NestC::b);
+    m.def("get_NestC", [](const NestC &c) { return c.value; });
+}
diff --git a/ext/pybind11/tests/test_operator_overloading.py b/ext/pybind11/tests/test_operator_overloading.py
index 02ccb9633..0d80e5ed3 100644
--- a/ext/pybind11/tests/test_operator_overloading.py
+++ b/ext/pybind11/tests/test_operator_overloading.py
@@ -1,8 +1,11 @@
-def test_operator_overloading():
-    from pybind11_tests import Vector2, Vector, ConstructorStats
+import pytest
+from pybind11_tests import operators as m
+from pybind11_tests import ConstructorStats
+
 
-    v1 = Vector2(1, 2)
-    v2 = Vector(3, -1)
+def test_operator_overloading():
+    v1 = m.Vector2(1, 2)
+    v2 = m.Vector(3, -1)
     assert str(v1) == "[1.000000, 2.000000]"
     assert str(v2) == "[3.000000, -1.000000]"
 
@@ -16,12 +19,25 @@ def test_operator_overloading():
     assert str(8 + v1) == "[9.000000, 10.000000]"
     assert str(8 * v1) == "[8.000000, 16.000000]"
     assert str(8 / v1) == "[8.000000, 4.000000]"
+    assert str(v1 * v2) == "[3.000000, -2.000000]"
+    assert str(v2 / v1) == "[3.000000, -0.500000]"
 
-    v1 += v2
+    v1 += 2 * v2
+    assert str(v1) == "[7.000000, 0.000000]"
+    v1 -= v2
+    assert str(v1) == "[4.000000, 1.000000]"
     v1 *= 2
     assert str(v1) == "[8.000000, 2.000000]"
+    v1 /= 16
+    assert str(v1) == "[0.500000, 0.125000]"
+    v1 *= v2
+    assert str(v1) == "[1.500000, -0.125000]"
+    v2 /= v1
+    assert str(v2) == "[2.000000, 8.000000]"
+
+    assert hash(v1) == 4
 
-    cstats = ConstructorStats.get(Vector2)
+    cstats = ConstructorStats.get(m.Vector2)
     assert cstats.alive() == 2
     del v1
     assert cstats.alive() == 1
@@ -32,9 +48,59 @@ def test_operator_overloading():
                                '[-7.000000, -6.000000]', '[9.000000, 10.000000]',
                                '[8.000000, 16.000000]', '[0.125000, 0.250000]',
                                '[7.000000, 6.000000]', '[9.000000, 10.000000]',
-                               '[8.000000, 16.000000]', '[8.000000, 4.000000]']
+                               '[8.000000, 16.000000]', '[8.000000, 4.000000]',
+                               '[3.000000, -2.000000]', '[3.000000, -0.500000]',
+                               '[6.000000, -2.000000]']
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0
     assert cstats.move_constructions >= 10
     assert cstats.copy_assignments == 0
     assert cstats.move_assignments == 0
+
+
+def test_operators_notimplemented():
+    """#393: need to return NotSupported to ensure correct arithmetic operator behavior"""
+
+    c1, c2 = m.C1(), m.C2()
+    assert c1 + c1 == 11
+    assert c2 + c2 == 22
+    assert c2 + c1 == 21
+    assert c1 + c2 == 12
+
+
+def test_nested():
+    """#328: first member in a class can't be used in operators"""
+
+    a = m.NestA()
+    b = m.NestB()
+    c = m.NestC()
+
+    a += 10
+    assert m.get_NestA(a) == 13
+    b.a += 100
+    assert m.get_NestA(b.a) == 103
+    c.b.a += 1000
+    assert m.get_NestA(c.b.a) == 1003
+    b -= 1
+    assert m.get_NestB(b) == 3
+    c.b -= 3
+    assert m.get_NestB(c.b) == 1
+    c *= 7
+    assert m.get_NestC(c) == 35
+
+    abase = a.as_base()
+    assert abase.value == -2
+    a.as_base().value += 44
+    assert abase.value == 42
+    assert c.b.a.as_base().value == -2
+    c.b.a.as_base().value += 44
+    assert c.b.a.as_base().value == 42
+
+    del c
+    pytest.gc_collect()
+    del a  # Should't delete while abase is still alive
+    pytest.gc_collect()
+
+    assert abase.value == 42
+    del abase, b
+    pytest.gc_collect()
diff --git a/ext/pybind11/tests/test_pickling.cpp b/ext/pybind11/tests/test_pickling.cpp
index 52b1dbc30..9dc63bda3 100644
--- a/ext/pybind11/tests/test_pickling.cpp
+++ b/ext/pybind11/tests/test_pickling.cpp
@@ -9,30 +9,28 @@
 
 #include "pybind11_tests.h"
 
-class Pickleable {
-public:
-    Pickleable(const std::string &value) : m_value(value) { }
-    const std::string &value() const { return m_value; }
-
-    void setExtra1(int extra1) { m_extra1 = extra1; }
-    void setExtra2(int extra2) { m_extra2 = extra2; }
-    int extra1() const { return m_extra1; }
-    int extra2() const { return m_extra2; }
-private:
-    std::string m_value;
-    int m_extra1 = 0;
-    int m_extra2 = 0;
-};
-
-class PickleableWithDict {
-public:
-    PickleableWithDict(const std::string &value) : value(value) { }
-
-    std::string value;
-    int extra;
-};
-
-test_initializer pickling([](py::module &m) {
+TEST_SUBMODULE(pickling, m) {
+    // test_roundtrip
+    class Pickleable {
+    public:
+        Pickleable(const std::string &value) : m_value(value) { }
+        const std::string &value() const { return m_value; }
+
+        void setExtra1(int extra1) { m_extra1 = extra1; }
+        void setExtra2(int extra2) { m_extra2 = extra2; }
+        int extra1() const { return m_extra1; }
+        int extra2() const { return m_extra2; }
+    private:
+        std::string m_value;
+        int m_extra1 = 0;
+        int m_extra2 = 0;
+    };
+
+    class PickleableNew : public Pickleable {
+    public:
+        using Pickleable::Pickleable;
+    };
+
     py::class_<Pickleable>(m, "Pickleable")
         .def(py::init<std::string>())
         .def("value", &Pickleable::value)
@@ -57,7 +55,38 @@ test_initializer pickling([](py::module &m) {
             p.setExtra2(t[2].cast<int>());
         });
 
+    py::class_<PickleableNew, Pickleable>(m, "PickleableNew")
+        .def(py::init<std::string>())
+        .def(py::pickle(
+            [](const PickleableNew &p) {
+                return py::make_tuple(p.value(), p.extra1(), p.extra2());
+            },
+            [](py::tuple t) {
+                if (t.size() != 3)
+                    throw std::runtime_error("Invalid state!");
+                auto p = PickleableNew(t[0].cast<std::string>());
+
+                p.setExtra1(t[1].cast<int>());
+                p.setExtra2(t[2].cast<int>());
+                return p;
+            }
+        ));
+
 #if !defined(PYPY_VERSION)
+    // test_roundtrip_with_dict
+    class PickleableWithDict {
+    public:
+        PickleableWithDict(const std::string &value) : value(value) { }
+
+        std::string value;
+        int extra;
+    };
+
+    class PickleableWithDictNew : public PickleableWithDict {
+    public:
+        using PickleableWithDict::PickleableWithDict;
+    };
+
     py::class_<PickleableWithDict>(m, "PickleableWithDict", py::dynamic_attr())
         .def(py::init<std::string>())
         .def_readwrite("value", &PickleableWithDict::value)
@@ -79,5 +108,23 @@ test_initializer pickling([](py::module &m) {
             /* Assign Python state */
             self.attr("__dict__") = t[2];
         });
+
+    py::class_<PickleableWithDictNew, PickleableWithDict>(m, "PickleableWithDictNew")
+        .def(py::init<std::string>())
+        .def(py::pickle(
+            [](py::object self) {
+                return py::make_tuple(self.attr("value"), self.attr("extra"), self.attr("__dict__"));
+            },
+            [](const py::tuple &t) {
+                if (t.size() != 3)
+                    throw std::runtime_error("Invalid state!");
+
+                auto cpp_state = PickleableWithDictNew(t[0].cast<std::string>());
+                cpp_state.extra = t[1].cast<int>();
+
+                auto py_state = t[2].cast<py::dict>();
+                return std::make_pair(cpp_state, py_state);
+            }
+        ));
 #endif
-});
+}
diff --git a/ext/pybind11/tests/test_pickling.py b/ext/pybind11/tests/test_pickling.py
index 548c618af..707d34786 100644
--- a/ext/pybind11/tests/test_pickling.py
+++ b/ext/pybind11/tests/test_pickling.py
@@ -1,4 +1,5 @@
 import pytest
+from pybind11_tests import pickling as m
 
 try:
     import cPickle as pickle  # Use cPickle on Python 2.7
@@ -6,10 +7,10 @@ except ImportError:
     import pickle
 
 
-def test_roundtrip():
-    from pybind11_tests import Pickleable
-
-    p = Pickleable("test_value")
+@pytest.mark.parametrize("cls_name", ["Pickleable", "PickleableNew"])
+def test_roundtrip(cls_name):
+    cls = getattr(m, cls_name)
+    p = cls("test_value")
     p.setExtra1(15)
     p.setExtra2(48)
 
@@ -21,10 +22,10 @@ def test_roundtrip():
 
 
 @pytest.unsupported_on_pypy
-def test_roundtrip_with_dict():
-    from pybind11_tests import PickleableWithDict
-
-    p = PickleableWithDict("test_value")
+@pytest.mark.parametrize("cls_name", ["PickleableWithDict", "PickleableWithDictNew"])
+def test_roundtrip_with_dict(cls_name):
+    cls = getattr(m, cls_name)
+    p = cls("test_value")
     p.extra = 15
     p.dynamic = "Attribute"
 
diff --git a/ext/pybind11/tests/test_python_types.cpp b/ext/pybind11/tests/test_python_types.cpp
deleted file mode 100644
index 5696239b4..000000000
--- a/ext/pybind11/tests/test_python_types.cpp
+++ /dev/null
@@ -1,495 +0,0 @@
-/*
-    tests/test_python_types.cpp -- singleton design pattern, static functions and
-    variables, passing and interacting with Python types
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-#include "constructor_stats.h"
-#include <pybind11/stl.h>
-
-#ifdef _WIN32
-#  include <io.h>
-#  include <fcntl.h>
-#endif
-
-#if defined(_MSC_VER)
-#  pragma warning(push)
-#  pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
-#endif
-
-class ExamplePythonTypes {
-public:
-    static ExamplePythonTypes *new_instance() {
-        auto *ptr = new ExamplePythonTypes();
-        print_created(ptr, "via new_instance");
-        return ptr;
-    }
-    ~ExamplePythonTypes() { print_destroyed(this); }
-
-    /* Create and return a Python dictionary */
-    py::dict get_dict() {
-        py::dict dict;
-        dict[py::str("key")] = py::str("value");
-        return dict;
-    }
-
-    /* Create and return a Python set */
-    py::set get_set() {
-        py::set set;
-        set.add(py::str("key1"));
-        set.add("key2");
-        set.add(std::string("key3"));
-        return set;
-    }
-
-    /* Create and return a C++ dictionary */
-    std::map<std::string, std::string> get_dict_2() {
-        std::map<std::string, std::string> result;
-        result["key"] = "value";
-        return result;
-    }
-
-    /* Create and return a C++ set */
-    std::set<std::string> get_set_2() {
-        std::set<std::string> result;
-        result.insert("key1");
-        result.insert("key2");
-        return result;
-    }
-
-    /* Create, manipulate, and return a Python list */
-    py::list get_list() {
-        py::list list;
-        list.append("value");
-        py::print("Entry at position 0:", list[0]);
-        list[0] = py::str("overwritten");
-        return list;
-    }
-
-    /* C++ STL data types are automatically casted */
-    std::vector<std::wstring> get_list_2() {
-        std::vector<std::wstring> list;
-        list.push_back(L"value");
-        return list;
-    }
-
-    /* C++ STL data types are automatically casted */
-    std::array<std::string, 2> get_array() {
-        return std::array<std::string, 2> {{ "array entry 1" , "array entry 2"}};
-    }
-
-    std::valarray<int> get_valarray() {
-        return std::valarray<int>({ 1, 4, 9 });
-    }
-
-    /* Easily iterate over a dictionary using a C++11 range-based for loop */
-    void print_dict(py::dict dict) {
-        for (auto item : dict)
-            py::print("key: {}, value={}"_s.format(item.first, item.second));
-    }
-
-    /* Easily iterate over a set using a C++11 range-based for loop */
-    void print_set(py::set set) {
-        for (auto item : set)
-            py::print("key:", item);
-    }
-
-    /* Easily iterate over a list using a C++11 range-based for loop */
-    void print_list(py::list list) {
-        int index = 0;
-        for (auto item : list)
-            py::print("list item {}: {}"_s.format(index++, item));
-    }
-
-    /* STL data types (such as maps) are automatically casted from Python */
-    void print_dict_2(const std::map<std::string, std::string> &dict) {
-        for (auto item : dict)
-            py::print("key: {}, value={}"_s.format(item.first, item.second));
-    }
-
-    /* STL data types (such as sets) are automatically casted from Python */
-    void print_set_2(const std::set<std::string> &set) {
-        for (auto item : set)
-            py::print("key:", item);
-    }
-
-    /* STL data types (such as vectors) are automatically casted from Python */
-    void print_list_2(std::vector<std::wstring> &list) {
-        int index = 0;
-        for (auto item : list)
-            py::print("list item {}: {}"_s.format(index++, item));
-    }
-
-    /* pybind automatically translates between C++11 and Python tuples */
-    std::pair<std::string, bool> pair_passthrough(std::pair<bool, std::string> input) {
-        return std::make_pair(input.second, input.first);
-    }
-
-    /* pybind automatically translates between C++11 and Python tuples */
-    std::tuple<int, std::string, bool> tuple_passthrough(std::tuple<bool, std::string, int> input) {
-        return std::make_tuple(std::get<2>(input), std::get<1>(input), std::get<0>(input));
-    }
-
-    /* STL data types (such as arrays) are automatically casted from Python */
-    void print_array(std::array<std::string, 2> &array) {
-        int index = 0;
-        for (auto item : array)
-            py::print("array item {}: {}"_s.format(index++, item));
-    }
-
-    void print_valarray(std::valarray<int> &varray) {
-        int index = 0;
-        for (auto item : varray)
-            py::print("valarray item {}: {}"_s.format(index++, item));
-    }
-
-    void throw_exception() {
-        throw std::runtime_error("This exception was intentionally thrown.");
-    }
-
-    py::bytes get_bytes_from_string() {
-        return (py::bytes) std::string("foo");
-    }
-
-    py::bytes get_bytes_from_str() {
-        return (py::bytes) py::str("bar", 3);
-    }
-
-    py::str get_str_from_string() {
-        return (py::str) std::string("baz");
-    }
-
-    py::str get_str_from_bytes() {
-        return (py::str) py::bytes("boo", 3);
-    }
-
-    void test_print(const py::object& obj) {
-        py::print(py::str(obj));
-        py::print(py::repr(obj));
-    }
-
-    static int value;
-    static const int value2;
-};
-
-int ExamplePythonTypes::value = 0;
-const int ExamplePythonTypes::value2 = 5;
-
-struct MoveOutContainer {
-    struct Value { int value; };
-
-    std::list<Value> move_list() const { return {{0}, {1}, {2}}; }
-};
-
-
-test_initializer python_types([](py::module &m) {
-    /* No constructor is explicitly defined below. An exception is raised when
-       trying to construct it directly from Python */
-    py::class_<ExamplePythonTypes>(m, "ExamplePythonTypes", "Example 2 documentation")
-        .def("get_dict", &ExamplePythonTypes::get_dict, "Return a Python dictionary")
-        .def("get_dict_2", &ExamplePythonTypes::get_dict_2, "Return a C++ dictionary")
-        .def("get_list", &ExamplePythonTypes::get_list, "Return a Python list")
-        .def("get_list_2", &ExamplePythonTypes::get_list_2, "Return a C++ list")
-        .def("get_set", &ExamplePythonTypes::get_set, "Return a Python set")
-        .def("get_set2", &ExamplePythonTypes::get_set_2, "Return a C++ set")
-        .def("get_array", &ExamplePythonTypes::get_array, "Return a C++ array")
-        .def("get_valarray", &ExamplePythonTypes::get_valarray, "Return a C++ valarray")
-        .def("print_dict", &ExamplePythonTypes::print_dict, "Print entries of a Python dictionary")
-        .def("print_dict_2", &ExamplePythonTypes::print_dict_2, "Print entries of a C++ dictionary")
-        .def("print_set", &ExamplePythonTypes::print_set, "Print entries of a Python set")
-        .def("print_set_2", &ExamplePythonTypes::print_set_2, "Print entries of a C++ set")
-        .def("print_list", &ExamplePythonTypes::print_list, "Print entries of a Python list")
-        .def("print_list_2", &ExamplePythonTypes::print_list_2, "Print entries of a C++ list")
-        .def("print_array", &ExamplePythonTypes::print_array, "Print entries of a C++ array")
-        .def("print_valarray", &ExamplePythonTypes::print_valarray, "Print entries of a C++ valarray")
-        .def("pair_passthrough", &ExamplePythonTypes::pair_passthrough, "Return a pair in reversed order")
-        .def("tuple_passthrough", &ExamplePythonTypes::tuple_passthrough, "Return a triple in reversed order")
-        .def("throw_exception", &ExamplePythonTypes::throw_exception, "Throw an exception")
-        .def("get_bytes_from_string", &ExamplePythonTypes::get_bytes_from_string, "py::bytes from std::string")
-        .def("get_bytes_from_str", &ExamplePythonTypes::get_bytes_from_str, "py::bytes from py::str")
-        .def("get_str_from_string", &ExamplePythonTypes::get_str_from_string, "py::str from std::string")
-        .def("get_str_from_bytes", &ExamplePythonTypes::get_str_from_bytes, "py::str from py::bytes")
-        .def("test_print", &ExamplePythonTypes::test_print, "test the print function")
-        .def_static("new_instance", &ExamplePythonTypes::new_instance, "Return an instance")
-        .def_readwrite_static("value", &ExamplePythonTypes::value, "Static value member")
-        .def_readonly_static("value2", &ExamplePythonTypes::value2, "Static value member (readonly)");
-
-    m.def("test_print_function", []() {
-        py::print("Hello, World!");
-        py::print(1, 2.0, "three", true, std::string("-- multiple args"));
-        auto args = py::make_tuple("and", "a", "custom", "separator");
-        py::print("*args", *args, "sep"_a="-");
-        py::print("no new line here", "end"_a=" -- ");
-        py::print("next print");
-
-        auto py_stderr = py::module::import("sys").attr("stderr");
-        py::print("this goes to stderr", "file"_a=py_stderr);
-
-        py::print("flush", "flush"_a=true);
-
-        py::print("{a} + {b} = {c}"_s.format("a"_a="py::print", "b"_a="str.format", "c"_a="this"));
-    });
-
-    m.def("test_str_format", []() {
-        auto s1 = "{} + {} = {}"_s.format(1, 2, 3);
-        auto s2 = "{a} + {b} = {c}"_s.format("a"_a=1, "b"_a=2, "c"_a=3);
-        return py::make_tuple(s1, s2);
-    });
-
-    m.def("test_dict_keyword_constructor", []() {
-        auto d1 = py::dict("x"_a=1, "y"_a=2);
-        auto d2 = py::dict("z"_a=3, **d1);
-        return d2;
-    });
-
-    m.def("test_accessor_api", [](py::object o) {
-        auto d = py::dict();
-
-        d["basic_attr"] = o.attr("basic_attr");
-
-        auto l = py::list();
-        for (const auto &item : o.attr("begin_end")) {
-            l.append(item);
-        }
-        d["begin_end"] = l;
-
-        d["operator[object]"] = o.attr("d")["operator[object]"_s];
-        d["operator[char *]"] = o.attr("d")["operator[char *]"];
-
-        d["attr(object)"] = o.attr("sub").attr("attr_obj");
-        d["attr(char *)"] = o.attr("sub").attr("attr_char");
-        try {
-            o.attr("sub").attr("missing").ptr();
-        } catch (const py::error_already_set &) {
-            d["missing_attr_ptr"] = "raised"_s;
-        }
-        try {
-            o.attr("missing").attr("doesn't matter");
-        } catch (const py::error_already_set &) {
-            d["missing_attr_chain"] = "raised"_s;
-        }
-
-        d["is_none"] = o.attr("basic_attr").is_none();
-
-        d["operator()"] = o.attr("func")(1);
-        d["operator*"] = o.attr("func")(*o.attr("begin_end"));
-
-        return d;
-    });
-
-    m.def("test_tuple_accessor", [](py::tuple existing_t) {
-        try {
-            existing_t[0] = 1;
-        } catch (const py::error_already_set &) {
-            // --> Python system error
-            // Only new tuples (refcount == 1) are mutable
-            auto new_t = py::tuple(3);
-            for (size_t i = 0; i < new_t.size(); ++i) {
-                new_t[i] = i;
-            }
-            return new_t;
-        }
-        return py::tuple();
-    });
-
-    m.def("test_accessor_assignment", []() {
-        auto l = py::list(1);
-        l[0] = 0;
-
-        auto d = py::dict();
-        d["get"] = l[0];
-        auto var = l[0];
-        d["deferred_get"] = var;
-        l[0] = 1;
-        d["set"] = l[0];
-        var = 99; // this assignment should not overwrite l[0]
-        d["deferred_set"] = l[0];
-        d["var"] = var;
-
-        return d;
-    });
-
-    bool has_optional = false, has_exp_optional = false;
-#ifdef PYBIND11_HAS_OPTIONAL
-    has_optional = true;
-    using opt_int = std::optional<int>;
-    m.def("double_or_zero", [](const opt_int& x) -> int {
-        return x.value_or(0) * 2;
-    });
-    m.def("half_or_none", [](int x) -> opt_int {
-        return x ? opt_int(x / 2) : opt_int();
-    });
-    m.def("test_nullopt", [](opt_int x) {
-        return x.value_or(42);
-    }, py::arg_v("x", std::nullopt, "None"));
-#endif
-
-#ifdef PYBIND11_HAS_EXP_OPTIONAL
-    has_exp_optional = true;
-    using exp_opt_int = std::experimental::optional<int>;
-    m.def("double_or_zero_exp", [](const exp_opt_int& x) -> int {
-        return x.value_or(0) * 2;
-    });
-    m.def("half_or_none_exp", [](int x) -> exp_opt_int {
-        return x ? exp_opt_int(x / 2) : exp_opt_int();
-    });
-    m.def("test_nullopt_exp", [](exp_opt_int x) {
-        return x.value_or(42);
-    }, py::arg_v("x", std::experimental::nullopt, "None"));
-#endif
-
-    m.attr("has_optional") = has_optional;
-    m.attr("has_exp_optional") = has_exp_optional;
-
-    m.def("test_default_constructors", []() {
-        return py::dict(
-            "str"_a=py::str(),
-            "bool"_a=py::bool_(),
-            "int"_a=py::int_(),
-            "float"_a=py::float_(),
-            "tuple"_a=py::tuple(),
-            "list"_a=py::list(),
-            "dict"_a=py::dict(),
-            "set"_a=py::set()
-        );
-    });
-
-    m.def("test_converting_constructors", [](py::dict d) {
-        return py::dict(
-            "str"_a=py::str(d["str"]),
-            "bool"_a=py::bool_(d["bool"]),
-            "int"_a=py::int_(d["int"]),
-            "float"_a=py::float_(d["float"]),
-            "tuple"_a=py::tuple(d["tuple"]),
-            "list"_a=py::list(d["list"]),
-            "dict"_a=py::dict(d["dict"]),
-            "set"_a=py::set(d["set"]),
-            "memoryview"_a=py::memoryview(d["memoryview"])
-        );
-    });
-
-    m.def("test_cast_functions", [](py::dict d) {
-        // When converting between Python types, obj.cast<T>() should be the same as T(obj)
-        return py::dict(
-            "str"_a=d["str"].cast<py::str>(),
-            "bool"_a=d["bool"].cast<py::bool_>(),
-            "int"_a=d["int"].cast<py::int_>(),
-            "float"_a=d["float"].cast<py::float_>(),
-            "tuple"_a=d["tuple"].cast<py::tuple>(),
-            "list"_a=d["list"].cast<py::list>(),
-            "dict"_a=d["dict"].cast<py::dict>(),
-            "set"_a=d["set"].cast<py::set>(),
-            "memoryview"_a=d["memoryview"].cast<py::memoryview>()
-        );
-    });
-
-    py::class_<MoveOutContainer::Value>(m, "MoveOutContainerValue")
-        .def_readonly("value", &MoveOutContainer::Value::value);
-
-    py::class_<MoveOutContainer>(m, "MoveOutContainer")
-        .def(py::init<>())
-        .def_property_readonly("move_list", &MoveOutContainer::move_list);
-
-    m.def("get_implicit_casting", []() {
-        py::dict d;
-        d["char*_i1"] = "abc";
-        const char *c2 = "abc";
-        d["char*_i2"] = c2;
-        d["char*_e"] = py::cast(c2);
-        d["char*_p"] = py::str(c2);
-
-        d["int_i1"] = 42;
-        int i = 42;
-        d["int_i2"] = i;
-        i++;
-        d["int_e"] = py::cast(i);
-        i++;
-        d["int_p"] = py::int_(i);
-
-        d["str_i1"] = std::string("str");
-        std::string s2("str1");
-        d["str_i2"] = s2;
-        s2[3] = '2';
-        d["str_e"] = py::cast(s2);
-        s2[3] = '3';
-        d["str_p"] = py::str(s2);
-
-        py::list l(2);
-        l[0] = 3;
-        l[1] = py::cast(6);
-        l.append(9);
-        l.append(py::cast(12));
-        l.append(py::int_(15));
-
-        return py::dict(
-            "d"_a=d,
-            "l"_a=l
-        );
-    });
-
-    // Some test characters in utf16 and utf32 encodings.  The last one (the 𝐀) contains a null byte
-    char32_t a32 = 0x61 /*a*/, z32 = 0x7a /*z*/, ib32 = 0x203d /*‽*/, cake32 = 0x1f382 /*🎂*/,              mathbfA32 = 0x1d400 /*𝐀*/;
-    char16_t b16 = 0x62 /*b*/, z16 = 0x7a,       ib16 = 0x203d,       cake16_1 = 0xd83c, cake16_2 = 0xdf82, mathbfA16_1 = 0xd835, mathbfA16_2 = 0xdc00;
-    std::wstring wstr;
-    wstr.push_back(0x61); // a
-    wstr.push_back(0x2e18); // ⸘
-    if (sizeof(wchar_t) == 2) { wstr.push_back(mathbfA16_1); wstr.push_back(mathbfA16_2); } // 𝐀, utf16
-    else { wstr.push_back((wchar_t) mathbfA32); } // 𝐀, utf32
-    wstr.push_back(0x7a); // z
-
-    m.def("good_utf8_string", []() { return std::string(u8"Say utf8\u203d \U0001f382 \U0001d400"); }); // Say utf8‽ 🎂 𝐀
-    m.def("good_utf16_string", [=]() { return std::u16string({ b16, ib16, cake16_1, cake16_2, mathbfA16_1, mathbfA16_2, z16 }); }); // b‽🎂𝐀z
-    m.def("good_utf32_string", [=]() { return std::u32string({ a32, mathbfA32, cake32, ib32, z32 }); }); // a𝐀🎂‽z
-    m.def("good_wchar_string", [=]() { return wstr; }); // a‽𝐀z
-    m.def("bad_utf8_string", []()  { return std::string("abc\xd0" "def"); });
-    m.def("bad_utf16_string", [=]() { return std::u16string({ b16, char16_t(0xd800), z16 }); });
-    // Under Python 2.7, invalid unicode UTF-32 characters don't appear to trigger UnicodeDecodeError
-    if (PY_MAJOR_VERSION >= 3)
-        m.def("bad_utf32_string", [=]() { return std::u32string({ a32, char32_t(0xd800), z32 }); });
-    if (PY_MAJOR_VERSION >= 3 || sizeof(wchar_t) == 2)
-        m.def("bad_wchar_string", [=]() { return std::wstring({ wchar_t(0x61), wchar_t(0xd800) }); });
-    m.def("u8_Z", []() -> char { return 'Z'; });
-    m.def("u8_eacute", []() -> char { return '\xe9'; });
-    m.def("u16_ibang", [=]() -> char16_t { return ib16; });
-    m.def("u32_mathbfA", [=]() -> char32_t { return mathbfA32; });
-    m.def("wchar_heart", []() -> wchar_t { return 0x2665; });
-
-    m.attr("wchar_size") = py::cast(sizeof(wchar_t));
-    m.def("ord_char", [](char c) -> int { return static_cast<unsigned char>(c); });
-    m.def("ord_char16", [](char16_t c) -> uint16_t { return c; });
-    m.def("ord_char32", [](char32_t c) -> uint32_t { return c; });
-    m.def("ord_wchar", [](wchar_t c) -> int { return c; });
-
-    m.def("return_none_string", []() -> std::string * { return nullptr; });
-    m.def("return_none_char",   []() -> const char *  { return nullptr; });
-    m.def("return_none_bool",   []() -> bool *        { return nullptr; });
-    m.def("return_none_int",    []() -> int *         { return nullptr; });
-    m.def("return_none_float",  []() -> float *       { return nullptr; });
-
-    m.def("return_capsule_with_destructor",
-        []() {
-            py::print("creating capsule");
-            return py::capsule([]() {
-                py::print("destructing capsule");
-            });
-        }
-    );
-
-    m.def("return_capsule_with_destructor_2",
-        []() {
-            py::print("creating capsule");
-            return py::capsule((void *) 1234, [](void *ptr) {
-                py::print("destructing capsule: {}"_s.format((size_t) ptr));
-            });
-        }
-    );
-});
-
-#if defined(_MSC_VER)
-#  pragma warning(pop)
-#endif
diff --git a/ext/pybind11/tests/test_python_types.py b/ext/pybind11/tests/test_python_types.py
deleted file mode 100644
index 7956c7cc6..000000000
--- a/ext/pybind11/tests/test_python_types.py
+++ /dev/null
@@ -1,535 +0,0 @@
-# Python < 3 needs this: coding=utf-8
-import pytest
-
-from pybind11_tests import ExamplePythonTypes, ConstructorStats, has_optional, has_exp_optional
-
-
-def test_repr():
-    # In Python 3.3+, repr() accesses __qualname__
-    assert "pybind11_type" in repr(type(ExamplePythonTypes))
-    assert "ExamplePythonTypes" in repr(ExamplePythonTypes)
-
-
-def test_static():
-    ExamplePythonTypes.value = 15
-    assert ExamplePythonTypes.value == 15
-    assert ExamplePythonTypes.value2 == 5
-
-    with pytest.raises(AttributeError) as excinfo:
-        ExamplePythonTypes.value2 = 15
-    assert str(excinfo.value) == "can't set attribute"
-
-
-def test_instance(capture):
-    with pytest.raises(TypeError) as excinfo:
-        ExamplePythonTypes()
-    assert str(excinfo.value) == "pybind11_tests.ExamplePythonTypes: No constructor defined!"
-
-    instance = ExamplePythonTypes.new_instance()
-
-    with capture:
-        dict_result = instance.get_dict()
-        dict_result['key2'] = 'value2'
-        instance.print_dict(dict_result)
-    assert capture.unordered == """
-        key: key, value=value
-        key: key2, value=value2
-    """
-    with capture:
-        dict_result = instance.get_dict_2()
-        dict_result['key2'] = 'value2'
-        instance.print_dict_2(dict_result)
-    assert capture.unordered == """
-        key: key, value=value
-        key: key2, value=value2
-    """
-    with capture:
-        set_result = instance.get_set()
-        set_result.add('key4')
-        instance.print_set(set_result)
-    assert capture.unordered == """
-        key: key1
-        key: key2
-        key: key3
-        key: key4
-    """
-    with capture:
-        set_result = instance.get_set2()
-        set_result.add('key3')
-        instance.print_set_2(set_result)
-    assert capture.unordered == """
-        key: key1
-        key: key2
-        key: key3
-    """
-    with capture:
-        list_result = instance.get_list()
-        list_result.append('value2')
-        instance.print_list(list_result)
-    assert capture.unordered == """
-        Entry at position 0: value
-        list item 0: overwritten
-        list item 1: value2
-    """
-    with capture:
-        list_result = instance.get_list_2()
-        list_result.append('value2')
-        instance.print_list_2(list_result)
-    assert capture.unordered == """
-        list item 0: value
-        list item 1: value2
-    """
-    with capture:
-        list_result = instance.get_list_2()
-        list_result.append('value2')
-        instance.print_list_2(tuple(list_result))
-    assert capture.unordered == """
-        list item 0: value
-        list item 1: value2
-    """
-    array_result = instance.get_array()
-    assert array_result == ['array entry 1', 'array entry 2']
-    with capture:
-        instance.print_array(array_result)
-    assert capture.unordered == """
-        array item 0: array entry 1
-        array item 1: array entry 2
-    """
-    varray_result = instance.get_valarray()
-    assert varray_result == [1, 4, 9]
-    with capture:
-        instance.print_valarray(varray_result)
-    assert capture.unordered == """
-        valarray item 0: 1
-        valarray item 1: 4
-        valarray item 2: 9
-    """
-    with pytest.raises(RuntimeError) as excinfo:
-        instance.throw_exception()
-    assert str(excinfo.value) == "This exception was intentionally thrown."
-
-    assert instance.pair_passthrough((True, "test")) == ("test", True)
-    assert instance.tuple_passthrough((True, "test", 5)) == (5, "test", True)
-    # Any sequence can be cast to a std::pair or std::tuple
-    assert instance.pair_passthrough([True, "test"]) == ("test", True)
-    assert instance.tuple_passthrough([True, "test", 5]) == (5, "test", True)
-
-    assert instance.get_bytes_from_string().decode() == "foo"
-    assert instance.get_bytes_from_str().decode() == "bar"
-    assert instance.get_str_from_string().encode().decode() == "baz"
-    assert instance.get_str_from_bytes().encode().decode() == "boo"
-
-    class A(object):
-        def __str__(self):
-            return "this is a str"
-
-        def __repr__(self):
-            return "this is a repr"
-
-    with capture:
-        instance.test_print(A())
-    assert capture == """
-        this is a str
-        this is a repr
-    """
-
-    cstats = ConstructorStats.get(ExamplePythonTypes)
-    assert cstats.alive() == 1
-    del instance
-    assert cstats.alive() == 0
-
-
-# PyPy does not seem to propagate the tp_docs field at the moment
-def test_class_docs(doc):
-    assert doc(ExamplePythonTypes) == "Example 2 documentation"
-
-
-def test_method_docs(doc):
-    assert doc(ExamplePythonTypes.get_dict) == """
-        get_dict(self: m.ExamplePythonTypes) -> dict
-
-        Return a Python dictionary
-    """
-    assert doc(ExamplePythonTypes.get_dict_2) == """
-        get_dict_2(self: m.ExamplePythonTypes) -> Dict[str, str]
-
-        Return a C++ dictionary
-    """
-    assert doc(ExamplePythonTypes.get_list) == """
-        get_list(self: m.ExamplePythonTypes) -> list
-
-        Return a Python list
-    """
-    assert doc(ExamplePythonTypes.get_list_2) == """
-        get_list_2(self: m.ExamplePythonTypes) -> List[str]
-
-        Return a C++ list
-    """
-    assert doc(ExamplePythonTypes.get_dict) == """
-        get_dict(self: m.ExamplePythonTypes) -> dict
-
-        Return a Python dictionary
-    """
-    assert doc(ExamplePythonTypes.get_set) == """
-        get_set(self: m.ExamplePythonTypes) -> set
-
-        Return a Python set
-    """
-    assert doc(ExamplePythonTypes.get_set2) == """
-        get_set2(self: m.ExamplePythonTypes) -> Set[str]
-
-        Return a C++ set
-    """
-    assert doc(ExamplePythonTypes.get_array) == """
-        get_array(self: m.ExamplePythonTypes) -> List[str[2]]
-
-        Return a C++ array
-    """
-    assert doc(ExamplePythonTypes.get_valarray) == """
-        get_valarray(self: m.ExamplePythonTypes) -> List[int]
-
-        Return a C++ valarray
-    """
-    assert doc(ExamplePythonTypes.print_dict) == """
-        print_dict(self: m.ExamplePythonTypes, arg0: dict) -> None
-
-        Print entries of a Python dictionary
-    """
-    assert doc(ExamplePythonTypes.print_dict_2) == """
-        print_dict_2(self: m.ExamplePythonTypes, arg0: Dict[str, str]) -> None
-
-        Print entries of a C++ dictionary
-    """
-    assert doc(ExamplePythonTypes.print_set) == """
-        print_set(self: m.ExamplePythonTypes, arg0: set) -> None
-
-        Print entries of a Python set
-    """
-    assert doc(ExamplePythonTypes.print_set_2) == """
-        print_set_2(self: m.ExamplePythonTypes, arg0: Set[str]) -> None
-
-        Print entries of a C++ set
-    """
-    assert doc(ExamplePythonTypes.print_list) == """
-        print_list(self: m.ExamplePythonTypes, arg0: list) -> None
-
-        Print entries of a Python list
-    """
-    assert doc(ExamplePythonTypes.print_list_2) == """
-        print_list_2(self: m.ExamplePythonTypes, arg0: List[str]) -> None
-
-        Print entries of a C++ list
-    """
-    assert doc(ExamplePythonTypes.print_array) == """
-        print_array(self: m.ExamplePythonTypes, arg0: List[str[2]]) -> None
-
-        Print entries of a C++ array
-    """
-    assert doc(ExamplePythonTypes.pair_passthrough) == """
-        pair_passthrough(self: m.ExamplePythonTypes, arg0: Tuple[bool, str]) -> Tuple[str, bool]
-
-        Return a pair in reversed order
-    """
-    assert doc(ExamplePythonTypes.tuple_passthrough) == """
-        tuple_passthrough(self: m.ExamplePythonTypes, arg0: Tuple[bool, str, int]) -> Tuple[int, str, bool]
-
-        Return a triple in reversed order
-    """  # noqa: E501 line too long
-    assert doc(ExamplePythonTypes.throw_exception) == """
-        throw_exception(self: m.ExamplePythonTypes) -> None
-
-        Throw an exception
-    """
-    assert doc(ExamplePythonTypes.new_instance) == """
-        new_instance() -> m.ExamplePythonTypes
-
-        Return an instance
-    """
-
-
-def test_module():
-    import pybind11_tests
-
-    assert pybind11_tests.__name__ == "pybind11_tests"
-    assert ExamplePythonTypes.__name__ == "ExamplePythonTypes"
-    assert ExamplePythonTypes.__module__ == "pybind11_tests"
-    assert ExamplePythonTypes.get_set.__name__ == "get_set"
-    assert ExamplePythonTypes.get_set.__module__ == "pybind11_tests"
-
-
-def test_print(capture):
-    from pybind11_tests import test_print_function
-
-    with capture:
-        test_print_function()
-    assert capture == """
-        Hello, World!
-        1 2.0 three True -- multiple args
-        *args-and-a-custom-separator
-        no new line here -- next print
-        flush
-        py::print + str.format = this
-    """
-    assert capture.stderr == "this goes to stderr"
-
-
-def test_str_api():
-    from pybind11_tests import test_str_format
-
-    s1, s2 = test_str_format()
-    assert s1 == "1 + 2 = 3"
-    assert s1 == s2
-
-
-def test_dict_api():
-    from pybind11_tests import test_dict_keyword_constructor
-
-    assert test_dict_keyword_constructor() == {"x": 1, "y": 2, "z": 3}
-
-
-def test_accessors():
-    from pybind11_tests import test_accessor_api, test_tuple_accessor, test_accessor_assignment
-
-    class SubTestObject:
-        attr_obj = 1
-        attr_char = 2
-
-    class TestObject:
-        basic_attr = 1
-        begin_end = [1, 2, 3]
-        d = {"operator[object]": 1, "operator[char *]": 2}
-        sub = SubTestObject()
-
-        def func(self, x, *args):
-            return self.basic_attr + x + sum(args)
-
-    d = test_accessor_api(TestObject())
-    assert d["basic_attr"] == 1
-    assert d["begin_end"] == [1, 2, 3]
-    assert d["operator[object]"] == 1
-    assert d["operator[char *]"] == 2
-    assert d["attr(object)"] == 1
-    assert d["attr(char *)"] == 2
-    assert d["missing_attr_ptr"] == "raised"
-    assert d["missing_attr_chain"] == "raised"
-    assert d["is_none"] is False
-    assert d["operator()"] == 2
-    assert d["operator*"] == 7
-
-    assert test_tuple_accessor(tuple()) == (0, 1, 2)
-
-    d = test_accessor_assignment()
-    assert d["get"] == 0
-    assert d["deferred_get"] == 0
-    assert d["set"] == 1
-    assert d["deferred_set"] == 1
-    assert d["var"] == 99
-
-
-@pytest.mark.skipif(not has_optional, reason='no <optional>')
-def test_optional():
-    from pybind11_tests import double_or_zero, half_or_none, test_nullopt
-
-    assert double_or_zero(None) == 0
-    assert double_or_zero(42) == 84
-    pytest.raises(TypeError, double_or_zero, 'foo')
-
-    assert half_or_none(0) is None
-    assert half_or_none(42) == 21
-    pytest.raises(TypeError, half_or_none, 'foo')
-
-    assert test_nullopt() == 42
-    assert test_nullopt(None) == 42
-    assert test_nullopt(42) == 42
-    assert test_nullopt(43) == 43
-
-
-@pytest.mark.skipif(not has_exp_optional, reason='no <experimental/optional>')
-def test_exp_optional():
-    from pybind11_tests import double_or_zero_exp, half_or_none_exp, test_nullopt_exp
-
-    assert double_or_zero_exp(None) == 0
-    assert double_or_zero_exp(42) == 84
-    pytest.raises(TypeError, double_or_zero_exp, 'foo')
-
-    assert half_or_none_exp(0) is None
-    assert half_or_none_exp(42) == 21
-    pytest.raises(TypeError, half_or_none_exp, 'foo')
-
-    assert test_nullopt_exp() == 42
-    assert test_nullopt_exp(None) == 42
-    assert test_nullopt_exp(42) == 42
-    assert test_nullopt_exp(43) == 43
-
-
-def test_constructors():
-    """C++ default and converting constructors are equivalent to type calls in Python"""
-    from pybind11_tests import (test_default_constructors, test_converting_constructors,
-                                test_cast_functions)
-
-    types = [str, bool, int, float, tuple, list, dict, set]
-    expected = {t.__name__: t() for t in types}
-    assert test_default_constructors() == expected
-
-    data = {
-        str: 42,
-        bool: "Not empty",
-        int: "42",
-        float: "+1e3",
-        tuple: range(3),
-        list: range(3),
-        dict: [("two", 2), ("one", 1), ("three", 3)],
-        set: [4, 4, 5, 6, 6, 6],
-        memoryview: b'abc'
-    }
-    inputs = {k.__name__: v for k, v in data.items()}
-    expected = {k.__name__: k(v) for k, v in data.items()}
-    assert test_converting_constructors(inputs) == expected
-    assert test_cast_functions(inputs) == expected
-
-
-def test_move_out_container():
-    """Properties use the `reference_internal` policy by default. If the underlying function
-    returns an rvalue, the policy is automatically changed to `move` to avoid referencing
-    a temporary. In case the return value is a container of user-defined types, the policy
-    also needs to be applied to the elements, not just the container."""
-    from pybind11_tests import MoveOutContainer
-
-    c = MoveOutContainer()
-    moved_out_list = c.move_list
-    assert [x.value for x in moved_out_list] == [0, 1, 2]
-
-
-def test_implicit_casting():
-    """Tests implicit casting when assigning or appending to dicts and lists."""
-    from pybind11_tests import get_implicit_casting
-
-    z = get_implicit_casting()
-    assert z['d'] == {
-        'char*_i1': 'abc', 'char*_i2': 'abc', 'char*_e': 'abc', 'char*_p': 'abc',
-        'str_i1': 'str', 'str_i2': 'str1', 'str_e': 'str2', 'str_p': 'str3',
-        'int_i1': 42, 'int_i2': 42, 'int_e': 43, 'int_p': 44
-    }
-    assert z['l'] == [3, 6, 9, 12, 15]
-
-
-def test_unicode_conversion():
-    """Tests unicode conversion and error reporting."""
-    import pybind11_tests
-    from pybind11_tests import (good_utf8_string, bad_utf8_string,
-                                good_utf16_string, bad_utf16_string,
-                                good_utf32_string,  # bad_utf32_string,
-                                good_wchar_string,  # bad_wchar_string,
-                                u8_Z, u8_eacute, u16_ibang, u32_mathbfA, wchar_heart)
-
-    assert good_utf8_string() == u"Say utf8‽ 🎂 𝐀"
-    assert good_utf16_string() == u"b‽🎂𝐀z"
-    assert good_utf32_string() == u"a𝐀🎂‽z"
-    assert good_wchar_string() == u"a⸘𝐀z"
-
-    with pytest.raises(UnicodeDecodeError):
-        bad_utf8_string()
-
-    with pytest.raises(UnicodeDecodeError):
-        bad_utf16_string()
-
-    # These are provided only if they actually fail (they don't when 32-bit and under Python 2.7)
-    if hasattr(pybind11_tests, "bad_utf32_string"):
-        with pytest.raises(UnicodeDecodeError):
-            pybind11_tests.bad_utf32_string()
-    if hasattr(pybind11_tests, "bad_wchar_string"):
-        with pytest.raises(UnicodeDecodeError):
-            pybind11_tests.bad_wchar_string()
-
-    assert u8_Z() == 'Z'
-    assert u8_eacute() == u'é'
-    assert u16_ibang() == u'‽'
-    assert u32_mathbfA() == u'𝐀'
-    assert wchar_heart() == u'♥'
-
-
-def test_single_char_arguments():
-    """Tests failures for passing invalid inputs to char-accepting functions"""
-    from pybind11_tests import ord_char, ord_char16, ord_char32, ord_wchar, wchar_size
-
-    def toobig_message(r):
-        return "Character code point not in range({0:#x})".format(r)
-    toolong_message = "Expected a character, but multi-character string found"
-
-    assert ord_char(u'a') == 0x61  # simple ASCII
-    assert ord_char(u'é') == 0xE9  # requires 2 bytes in utf-8, but can be stuffed in a char
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_char(u'Ā') == 0x100  # requires 2 bytes, doesn't fit in a char
-    assert str(excinfo.value) == toobig_message(0x100)
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_char(u'ab')
-    assert str(excinfo.value) == toolong_message
-
-    assert ord_char16(u'a') == 0x61
-    assert ord_char16(u'é') == 0xE9
-    assert ord_char16(u'Ā') == 0x100
-    assert ord_char16(u'‽') == 0x203d
-    assert ord_char16(u'♥') == 0x2665
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_char16(u'🎂') == 0x1F382  # requires surrogate pair
-    assert str(excinfo.value) == toobig_message(0x10000)
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_char16(u'aa')
-    assert str(excinfo.value) == toolong_message
-
-    assert ord_char32(u'a') == 0x61
-    assert ord_char32(u'é') == 0xE9
-    assert ord_char32(u'Ā') == 0x100
-    assert ord_char32(u'‽') == 0x203d
-    assert ord_char32(u'♥') == 0x2665
-    assert ord_char32(u'🎂') == 0x1F382
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_char32(u'aa')
-    assert str(excinfo.value) == toolong_message
-
-    assert ord_wchar(u'a') == 0x61
-    assert ord_wchar(u'é') == 0xE9
-    assert ord_wchar(u'Ā') == 0x100
-    assert ord_wchar(u'‽') == 0x203d
-    assert ord_wchar(u'♥') == 0x2665
-    if wchar_size == 2:
-        with pytest.raises(ValueError) as excinfo:
-            assert ord_wchar(u'🎂') == 0x1F382  # requires surrogate pair
-        assert str(excinfo.value) == toobig_message(0x10000)
-    else:
-        assert ord_wchar(u'🎂') == 0x1F382
-    with pytest.raises(ValueError) as excinfo:
-        assert ord_wchar(u'aa')
-    assert str(excinfo.value) == toolong_message
-
-
-def test_builtins_cast_return_none():
-    """Casters produced with PYBIND11_TYPE_CASTER() should convert nullptr to None"""
-    import pybind11_tests as m
-
-    assert m.return_none_string() is None
-    assert m.return_none_char() is None
-    assert m.return_none_bool() is None
-    assert m.return_none_int() is None
-    assert m.return_none_float() is None
-
-
-def test_capsule_with_destructor(capture):
-    import pybind11_tests as m
-    with capture:
-        a = m.return_capsule_with_destructor()
-        del a
-        pytest.gc_collect()
-    assert capture.unordered == """
-        creating capsule
-        destructing capsule
-    """
-
-    with capture:
-        a = m.return_capsule_with_destructor_2()
-        del a
-        pytest.gc_collect()
-    assert capture.unordered == """
-        creating capsule
-        destructing capsule: 1234
-    """
diff --git a/ext/pybind11/tests/test_pytypes.cpp b/ext/pybind11/tests/test_pytypes.cpp
new file mode 100644
index 000000000..a962f0ccc
--- /dev/null
+++ b/ext/pybind11/tests/test_pytypes.cpp
@@ -0,0 +1,272 @@
+/*
+    tests/test_pytypes.cpp -- Python type casters
+
+    Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+
+
+TEST_SUBMODULE(pytypes, m) {
+    // test_list
+    m.def("get_list", []() {
+        py::list list;
+        list.append("value");
+        py::print("Entry at position 0:", list[0]);
+        list[0] = py::str("overwritten");
+        return list;
+    });
+    m.def("print_list", [](py::list list) {
+        int index = 0;
+        for (auto item : list)
+            py::print("list item {}: {}"_s.format(index++, item));
+    });
+
+    // test_set
+    m.def("get_set", []() {
+        py::set set;
+        set.add(py::str("key1"));
+        set.add("key2");
+        set.add(std::string("key3"));
+        return set;
+    });
+    m.def("print_set", [](py::set set) {
+        for (auto item : set)
+            py::print("key:", item);
+    });
+
+    // test_dict
+    m.def("get_dict", []() { return py::dict("key"_a="value"); });
+    m.def("print_dict", [](py::dict dict) {
+        for (auto item : dict)
+            py::print("key: {}, value={}"_s.format(item.first, item.second));
+    });
+    m.def("dict_keyword_constructor", []() {
+        auto d1 = py::dict("x"_a=1, "y"_a=2);
+        auto d2 = py::dict("z"_a=3, **d1);
+        return d2;
+    });
+
+    // test_str
+    m.def("str_from_string", []() { return py::str(std::string("baz")); });
+    m.def("str_from_bytes", []() { return py::str(py::bytes("boo", 3)); });
+    m.def("str_from_object", [](const py::object& obj) { return py::str(obj); });
+    m.def("repr_from_object", [](const py::object& obj) { return py::repr(obj); });
+
+    m.def("str_format", []() {
+        auto s1 = "{} + {} = {}"_s.format(1, 2, 3);
+        auto s2 = "{a} + {b} = {c}"_s.format("a"_a=1, "b"_a=2, "c"_a=3);
+        return py::make_tuple(s1, s2);
+    });
+
+    // test_bytes
+    m.def("bytes_from_string", []() { return py::bytes(std::string("foo")); });
+    m.def("bytes_from_str", []() { return py::bytes(py::str("bar", 3)); });
+
+    // test_capsule
+    m.def("return_capsule_with_destructor", []() {
+        py::print("creating capsule");
+        return py::capsule([]() {
+            py::print("destructing capsule");
+        });
+    });
+
+    m.def("return_capsule_with_destructor_2", []() {
+        py::print("creating capsule");
+        return py::capsule((void *) 1234, [](void *ptr) {
+            py::print("destructing capsule: {}"_s.format((size_t) ptr));
+        });
+    });
+
+    m.def("return_capsule_with_name_and_destructor", []() {
+        auto capsule = py::capsule((void *) 1234, "pointer type description", [](PyObject *ptr) {
+            if (ptr) {
+                auto name = PyCapsule_GetName(ptr);
+                py::print("destructing capsule ({}, '{}')"_s.format(
+                    (size_t) PyCapsule_GetPointer(ptr, name), name
+                ));
+            }
+        });
+        void *contents = capsule;
+        py::print("created capsule ({}, '{}')"_s.format((size_t) contents, capsule.name()));
+        return capsule;
+    });
+
+    // test_accessors
+    m.def("accessor_api", [](py::object o) {
+        auto d = py::dict();
+
+        d["basic_attr"] = o.attr("basic_attr");
+
+        auto l = py::list();
+        for (const auto &item : o.attr("begin_end")) {
+            l.append(item);
+        }
+        d["begin_end"] = l;
+
+        d["operator[object]"] = o.attr("d")["operator[object]"_s];
+        d["operator[char *]"] = o.attr("d")["operator[char *]"];
+
+        d["attr(object)"] = o.attr("sub").attr("attr_obj");
+        d["attr(char *)"] = o.attr("sub").attr("attr_char");
+        try {
+            o.attr("sub").attr("missing").ptr();
+        } catch (const py::error_already_set &) {
+            d["missing_attr_ptr"] = "raised"_s;
+        }
+        try {
+            o.attr("missing").attr("doesn't matter");
+        } catch (const py::error_already_set &) {
+            d["missing_attr_chain"] = "raised"_s;
+        }
+
+        d["is_none"] = o.attr("basic_attr").is_none();
+
+        d["operator()"] = o.attr("func")(1);
+        d["operator*"] = o.attr("func")(*o.attr("begin_end"));
+
+        // Test implicit conversion
+        py::list implicit_list = o.attr("begin_end");
+        d["implicit_list"] = implicit_list;
+        py::dict implicit_dict = o.attr("__dict__");
+        d["implicit_dict"] = implicit_dict;
+
+        return d;
+    });
+
+    m.def("tuple_accessor", [](py::tuple existing_t) {
+        try {
+            existing_t[0] = 1;
+        } catch (const py::error_already_set &) {
+            // --> Python system error
+            // Only new tuples (refcount == 1) are mutable
+            auto new_t = py::tuple(3);
+            for (size_t i = 0; i < new_t.size(); ++i) {
+                new_t[i] = i;
+            }
+            return new_t;
+        }
+        return py::tuple();
+    });
+
+    m.def("accessor_assignment", []() {
+        auto l = py::list(1);
+        l[0] = 0;
+
+        auto d = py::dict();
+        d["get"] = l[0];
+        auto var = l[0];
+        d["deferred_get"] = var;
+        l[0] = 1;
+        d["set"] = l[0];
+        var = 99; // this assignment should not overwrite l[0]
+        d["deferred_set"] = l[0];
+        d["var"] = var;
+
+        return d;
+    });
+
+    // test_constructors
+    m.def("default_constructors", []() {
+        return py::dict(
+            "str"_a=py::str(),
+            "bool"_a=py::bool_(),
+            "int"_a=py::int_(),
+            "float"_a=py::float_(),
+            "tuple"_a=py::tuple(),
+            "list"_a=py::list(),
+            "dict"_a=py::dict(),
+            "set"_a=py::set()
+        );
+    });
+
+    m.def("converting_constructors", [](py::dict d) {
+        return py::dict(
+            "str"_a=py::str(d["str"]),
+            "bool"_a=py::bool_(d["bool"]),
+            "int"_a=py::int_(d["int"]),
+            "float"_a=py::float_(d["float"]),
+            "tuple"_a=py::tuple(d["tuple"]),
+            "list"_a=py::list(d["list"]),
+            "dict"_a=py::dict(d["dict"]),
+            "set"_a=py::set(d["set"]),
+            "memoryview"_a=py::memoryview(d["memoryview"])
+        );
+    });
+
+    m.def("cast_functions", [](py::dict d) {
+        // When converting between Python types, obj.cast<T>() should be the same as T(obj)
+        return py::dict(
+            "str"_a=d["str"].cast<py::str>(),
+            "bool"_a=d["bool"].cast<py::bool_>(),
+            "int"_a=d["int"].cast<py::int_>(),
+            "float"_a=d["float"].cast<py::float_>(),
+            "tuple"_a=d["tuple"].cast<py::tuple>(),
+            "list"_a=d["list"].cast<py::list>(),
+            "dict"_a=d["dict"].cast<py::dict>(),
+            "set"_a=d["set"].cast<py::set>(),
+            "memoryview"_a=d["memoryview"].cast<py::memoryview>()
+        );
+    });
+
+    m.def("get_implicit_casting", []() {
+        py::dict d;
+        d["char*_i1"] = "abc";
+        const char *c2 = "abc";
+        d["char*_i2"] = c2;
+        d["char*_e"] = py::cast(c2);
+        d["char*_p"] = py::str(c2);
+
+        d["int_i1"] = 42;
+        int i = 42;
+        d["int_i2"] = i;
+        i++;
+        d["int_e"] = py::cast(i);
+        i++;
+        d["int_p"] = py::int_(i);
+
+        d["str_i1"] = std::string("str");
+        std::string s2("str1");
+        d["str_i2"] = s2;
+        s2[3] = '2';
+        d["str_e"] = py::cast(s2);
+        s2[3] = '3';
+        d["str_p"] = py::str(s2);
+
+        py::list l(2);
+        l[0] = 3;
+        l[1] = py::cast(6);
+        l.append(9);
+        l.append(py::cast(12));
+        l.append(py::int_(15));
+
+        return py::dict(
+            "d"_a=d,
+            "l"_a=l
+        );
+    });
+
+    // test_print
+    m.def("print_function", []() {
+        py::print("Hello, World!");
+        py::print(1, 2.0, "three", true, std::string("-- multiple args"));
+        auto args = py::make_tuple("and", "a", "custom", "separator");
+        py::print("*args", *args, "sep"_a="-");
+        py::print("no new line here", "end"_a=" -- ");
+        py::print("next print");
+
+        auto py_stderr = py::module::import("sys").attr("stderr");
+        py::print("this goes to stderr", "file"_a=py_stderr);
+
+        py::print("flush", "flush"_a=true);
+
+        py::print("{a} + {b} = {c}"_s.format("a"_a="py::print", "b"_a="str.format", "c"_a="this"));
+    });
+
+    m.def("print_failure", []() { py::print(42, UnregisteredType()); });
+
+    m.def("hash_function", [](py::object obj) { return py::hash(obj); });
+}
diff --git a/ext/pybind11/tests/test_pytypes.py b/ext/pybind11/tests/test_pytypes.py
new file mode 100644
index 000000000..94c90a909
--- /dev/null
+++ b/ext/pybind11/tests/test_pytypes.py
@@ -0,0 +1,240 @@
+import pytest
+import sys
+
+from pybind11_tests import pytypes as m
+from pybind11_tests import debug_enabled
+
+
+def test_list(capture, doc):
+    with capture:
+        l = m.get_list()
+        assert l == ["overwritten"]
+
+        l.append("value2")
+        m.print_list(l)
+    assert capture.unordered == """
+        Entry at position 0: value
+        list item 0: overwritten
+        list item 1: value2
+    """
+
+    assert doc(m.get_list) == "get_list() -> list"
+    assert doc(m.print_list) == "print_list(arg0: list) -> None"
+
+
+def test_set(capture, doc):
+    s = m.get_set()
+    assert s == {"key1", "key2", "key3"}
+
+    with capture:
+        s.add("key4")
+        m.print_set(s)
+    assert capture.unordered == """
+        key: key1
+        key: key2
+        key: key3
+        key: key4
+    """
+
+    assert doc(m.get_list) == "get_list() -> list"
+    assert doc(m.print_list) == "print_list(arg0: list) -> None"
+
+
+def test_dict(capture, doc):
+    d = m.get_dict()
+    assert d == {"key": "value"}
+
+    with capture:
+        d["key2"] = "value2"
+        m.print_dict(d)
+    assert capture.unordered == """
+        key: key, value=value
+        key: key2, value=value2
+    """
+
+    assert doc(m.get_dict) == "get_dict() -> dict"
+    assert doc(m.print_dict) == "print_dict(arg0: dict) -> None"
+
+    assert m.dict_keyword_constructor() == {"x": 1, "y": 2, "z": 3}
+
+
+def test_str(doc):
+    assert m.str_from_string().encode().decode() == "baz"
+    assert m.str_from_bytes().encode().decode() == "boo"
+
+    assert doc(m.str_from_bytes) == "str_from_bytes() -> str"
+
+    class A(object):
+        def __str__(self):
+            return "this is a str"
+
+        def __repr__(self):
+            return "this is a repr"
+
+    assert m.str_from_object(A()) == "this is a str"
+    assert m.repr_from_object(A()) == "this is a repr"
+
+    s1, s2 = m.str_format()
+    assert s1 == "1 + 2 = 3"
+    assert s1 == s2
+
+
+def test_bytes(doc):
+    assert m.bytes_from_string().decode() == "foo"
+    assert m.bytes_from_str().decode() == "bar"
+
+    assert doc(m.bytes_from_str) == "bytes_from_str() -> {}".format(
+        "bytes" if sys.version_info[0] == 3 else "str"
+    )
+
+
+def test_capsule(capture):
+    pytest.gc_collect()
+    with capture:
+        a = m.return_capsule_with_destructor()
+        del a
+        pytest.gc_collect()
+    assert capture.unordered == """
+        creating capsule
+        destructing capsule
+    """
+
+    with capture:
+        a = m.return_capsule_with_destructor_2()
+        del a
+        pytest.gc_collect()
+    assert capture.unordered == """
+        creating capsule
+        destructing capsule: 1234
+    """
+
+    with capture:
+        a = m.return_capsule_with_name_and_destructor()
+        del a
+        pytest.gc_collect()
+    assert capture.unordered == """
+        created capsule (1234, 'pointer type description')
+        destructing capsule (1234, 'pointer type description')
+    """
+
+
+def test_accessors():
+    class SubTestObject:
+        attr_obj = 1
+        attr_char = 2
+
+    class TestObject:
+        basic_attr = 1
+        begin_end = [1, 2, 3]
+        d = {"operator[object]": 1, "operator[char *]": 2}
+        sub = SubTestObject()
+
+        def func(self, x, *args):
+            return self.basic_attr + x + sum(args)
+
+    d = m.accessor_api(TestObject())
+    assert d["basic_attr"] == 1
+    assert d["begin_end"] == [1, 2, 3]
+    assert d["operator[object]"] == 1
+    assert d["operator[char *]"] == 2
+    assert d["attr(object)"] == 1
+    assert d["attr(char *)"] == 2
+    assert d["missing_attr_ptr"] == "raised"
+    assert d["missing_attr_chain"] == "raised"
+    assert d["is_none"] is False
+    assert d["operator()"] == 2
+    assert d["operator*"] == 7
+    assert d["implicit_list"] == [1, 2, 3]
+    assert all(x in TestObject.__dict__ for x in d["implicit_dict"])
+
+    assert m.tuple_accessor(tuple()) == (0, 1, 2)
+
+    d = m.accessor_assignment()
+    assert d["get"] == 0
+    assert d["deferred_get"] == 0
+    assert d["set"] == 1
+    assert d["deferred_set"] == 1
+    assert d["var"] == 99
+
+
+def test_constructors():
+    """C++ default and converting constructors are equivalent to type calls in Python"""
+    types = [str, bool, int, float, tuple, list, dict, set]
+    expected = {t.__name__: t() for t in types}
+    assert m.default_constructors() == expected
+
+    data = {
+        str: 42,
+        bool: "Not empty",
+        int: "42",
+        float: "+1e3",
+        tuple: range(3),
+        list: range(3),
+        dict: [("two", 2), ("one", 1), ("three", 3)],
+        set: [4, 4, 5, 6, 6, 6],
+        memoryview: b'abc'
+    }
+    inputs = {k.__name__: v for k, v in data.items()}
+    expected = {k.__name__: k(v) for k, v in data.items()}
+
+    assert m.converting_constructors(inputs) == expected
+    assert m.cast_functions(inputs) == expected
+
+    # Converting constructors and cast functions should just reference rather
+    # than copy when no conversion is needed:
+    noconv1 = m.converting_constructors(expected)
+    for k in noconv1:
+        assert noconv1[k] is expected[k]
+
+    noconv2 = m.cast_functions(expected)
+    for k in noconv2:
+        assert noconv2[k] is expected[k]
+
+
+def test_implicit_casting():
+    """Tests implicit casting when assigning or appending to dicts and lists."""
+    z = m.get_implicit_casting()
+    assert z['d'] == {
+        'char*_i1': 'abc', 'char*_i2': 'abc', 'char*_e': 'abc', 'char*_p': 'abc',
+        'str_i1': 'str', 'str_i2': 'str1', 'str_e': 'str2', 'str_p': 'str3',
+        'int_i1': 42, 'int_i2': 42, 'int_e': 43, 'int_p': 44
+    }
+    assert z['l'] == [3, 6, 9, 12, 15]
+
+
+def test_print(capture):
+    with capture:
+        m.print_function()
+    assert capture == """
+        Hello, World!
+        1 2.0 three True -- multiple args
+        *args-and-a-custom-separator
+        no new line here -- next print
+        flush
+        py::print + str.format = this
+    """
+    assert capture.stderr == "this goes to stderr"
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.print_failure()
+    assert str(excinfo.value) == "make_tuple(): unable to convert " + (
+        "argument of type 'UnregisteredType' to Python object"
+        if debug_enabled else
+        "arguments to Python object (compile in debug mode for details)"
+    )
+
+
+def test_hash():
+    class Hashable(object):
+        def __init__(self, value):
+            self.value = value
+
+        def __hash__(self):
+            return self.value
+
+    class Unhashable(object):
+        __hash__ = None
+
+    assert m.hash_function(Hashable(42)) == 42
+    with pytest.raises(TypeError):
+        m.hash_function(Unhashable())
diff --git a/ext/pybind11/tests/test_sequences_and_iterators.cpp b/ext/pybind11/tests/test_sequences_and_iterators.cpp
index c2051fadb..a45521256 100644
--- a/ext/pybind11/tests/test_sequences_and_iterators.cpp
+++ b/ext/pybind11/tests/test_sequences_and_iterators.cpp
@@ -13,146 +13,6 @@
 #include <pybind11/operators.h>
 #include <pybind11/stl.h>
 
-class Sequence {
-public:
-    Sequence(size_t size) : m_size(size) {
-        print_created(this, "of size", m_size);
-        m_data = new float[size];
-        memset(m_data, 0, sizeof(float) * size);
-    }
-
-    Sequence(const std::vector<float> &value) : m_size(value.size()) {
-        print_created(this, "of size", m_size, "from std::vector");
-        m_data = new float[m_size];
-        memcpy(m_data, &value[0], sizeof(float) * m_size);
-    }
-
-    Sequence(const Sequence &s) : m_size(s.m_size) {
-        print_copy_created(this);
-        m_data = new float[m_size];
-        memcpy(m_data, s.m_data, sizeof(float)*m_size);
-    }
-
-    Sequence(Sequence &&s) : m_size(s.m_size), m_data(s.m_data) {
-        print_move_created(this);
-        s.m_size = 0;
-        s.m_data = nullptr;
-    }
-
-    ~Sequence() {
-        print_destroyed(this);
-        delete[] m_data;
-    }
-
-    Sequence &operator=(const Sequence &s) {
-        if (&s != this) {
-            delete[] m_data;
-            m_size = s.m_size;
-            m_data = new float[m_size];
-            memcpy(m_data, s.m_data, sizeof(float)*m_size);
-        }
-
-        print_copy_assigned(this);
-
-        return *this;
-    }
-
-    Sequence &operator=(Sequence &&s) {
-        if (&s != this) {
-            delete[] m_data;
-            m_size = s.m_size;
-            m_data = s.m_data;
-            s.m_size = 0;
-            s.m_data = nullptr;
-        }
-
-        print_move_assigned(this);
-
-        return *this;
-    }
-
-    bool operator==(const Sequence &s) const {
-        if (m_size != s.size())
-            return false;
-        for (size_t i=0; i<m_size; ++i)
-            if (m_data[i] != s[i])
-                return false;
-        return true;
-    }
-
-    bool operator!=(const Sequence &s) const {
-        return !operator==(s);
-    }
-
-    float operator[](size_t index) const {
-        return m_data[index];
-    }
-
-    float &operator[](size_t index) {
-        return m_data[index];
-    }
-
-    bool contains(float v) const {
-        for (size_t i=0; i<m_size; ++i)
-            if (v == m_data[i])
-                return true;
-        return false;
-    }
-
-    Sequence reversed() const {
-        Sequence result(m_size);
-        for (size_t i=0; i<m_size; ++i)
-            result[m_size-i-1] = m_data[i];
-        return result;
-    }
-
-    size_t size() const { return m_size; }
-
-    const float *begin() const { return m_data; }
-    const float *end() const { return m_data+m_size; }
-
-private:
-    size_t m_size;
-    float *m_data;
-};
-
-class IntPairs {
-public:
-    IntPairs(std::vector<std::pair<int, int>> data) : data_(std::move(data)) {}
-    const std::pair<int, int>* begin() const { return data_.data(); }
-
-private:
-    std::vector<std::pair<int, int>> data_;
-};
-
-// Interface of a map-like object that isn't (directly) an unordered_map, but provides some basic
-// map-like functionality.
-class StringMap {
-public:
-    StringMap() = default;
-    StringMap(std::unordered_map<std::string, std::string> init)
-        : map(std::move(init)) {}
-
-    void set(std::string key, std::string val) {
-        map[key] = val;
-    }
-
-    std::string get(std::string key) const {
-        return map.at(key);
-    }
-
-    size_t size() const {
-        return map.size();
-    }
-
-private:
-    std::unordered_map<std::string, std::string> map;
-
-public:
-    decltype(map.cbegin()) begin() const { return map.cbegin(); }
-    decltype(map.cend()) end() const { return map.cend(); }
-};
-
 template<typename T>
 class NonZeroIterator {
     const T* ptr_;
@@ -210,66 +70,164 @@ py::list test_random_access_iterator(PythonType x) {
     return checks;
 }
 
-test_initializer sequences_and_iterators([](py::module &pm) {
-    auto m = pm.def_submodule("sequences_and_iterators");
+TEST_SUBMODULE(sequences_and_iterators, m) {
+
+    // test_sequence
+    class Sequence {
+    public:
+        Sequence(size_t size) : m_size(size) {
+            print_created(this, "of size", m_size);
+            m_data = new float[size];
+            memset(m_data, 0, sizeof(float) * size);
+        }
+        Sequence(const std::vector<float> &value) : m_size(value.size()) {
+            print_created(this, "of size", m_size, "from std::vector");
+            m_data = new float[m_size];
+            memcpy(m_data, &value[0], sizeof(float) * m_size);
+        }
+        Sequence(const Sequence &s) : m_size(s.m_size) {
+            print_copy_created(this);
+            m_data = new float[m_size];
+            memcpy(m_data, s.m_data, sizeof(float)*m_size);
+        }
+        Sequence(Sequence &&s) : m_size(s.m_size), m_data(s.m_data) {
+            print_move_created(this);
+            s.m_size = 0;
+            s.m_data = nullptr;
+        }
+
+        ~Sequence() { print_destroyed(this); delete[] m_data; }
 
-    py::class_<Sequence> seq(m, "Sequence");
+        Sequence &operator=(const Sequence &s) {
+            if (&s != this) {
+                delete[] m_data;
+                m_size = s.m_size;
+                m_data = new float[m_size];
+                memcpy(m_data, s.m_data, sizeof(float)*m_size);
+            }
+            print_copy_assigned(this);
+            return *this;
+        }
 
-    seq.def(py::init<size_t>())
-       .def(py::init<const std::vector<float>&>())
-       /// Bare bones interface
-       .def("__getitem__", [](const Sequence &s, size_t i) {
-            if (i >= s.size())
-                throw py::index_error();
+        Sequence &operator=(Sequence &&s) {
+            if (&s != this) {
+                delete[] m_data;
+                m_size = s.m_size;
+                m_data = s.m_data;
+                s.m_size = 0;
+                s.m_data = nullptr;
+            }
+            print_move_assigned(this);
+            return *this;
+        }
+
+        bool operator==(const Sequence &s) const {
+            if (m_size != s.size()) return false;
+            for (size_t i = 0; i < m_size; ++i)
+                if (m_data[i] != s[i])
+                    return false;
+            return true;
+        }
+        bool operator!=(const Sequence &s) const { return !operator==(s); }
+
+        float operator[](size_t index) const { return m_data[index]; }
+        float &operator[](size_t index) { return m_data[index]; }
+
+        bool contains(float v) const {
+            for (size_t i = 0; i < m_size; ++i)
+                if (v == m_data[i])
+                    return true;
+            return false;
+        }
+
+        Sequence reversed() const {
+            Sequence result(m_size);
+            for (size_t i = 0; i < m_size; ++i)
+                result[m_size - i - 1] = m_data[i];
+            return result;
+        }
+
+        size_t size() const { return m_size; }
+
+        const float *begin() const { return m_data; }
+        const float *end() const { return m_data+m_size; }
+
+    private:
+        size_t m_size;
+        float *m_data;
+    };
+    py::class_<Sequence>(m, "Sequence")
+        .def(py::init<size_t>())
+        .def(py::init<const std::vector<float>&>())
+        /// Bare bones interface
+        .def("__getitem__", [](const Sequence &s, size_t i) {
+            if (i >= s.size()) throw py::index_error();
             return s[i];
         })
-       .def("__setitem__", [](Sequence &s, size_t i, float v) {
-            if (i >= s.size())
-                throw py::index_error();
+        .def("__setitem__", [](Sequence &s, size_t i, float v) {
+            if (i >= s.size()) throw py::index_error();
             s[i] = v;
         })
-       .def("__len__", &Sequence::size)
-       /// Optional sequence protocol operations
-       .def("__iter__", [](const Sequence &s) { return py::make_iterator(s.begin(), s.end()); },
-                        py::keep_alive<0, 1>() /* Essential: keep object alive while iterator exists */)
-       .def("__contains__", [](const Sequence &s, float v) { return s.contains(v); })
-       .def("__reversed__", [](const Sequence &s) -> Sequence { return s.reversed(); })
-       /// Slicing protocol (optional)
-       .def("__getitem__", [](const Sequence &s, py::slice slice) -> Sequence* {
+        .def("__len__", &Sequence::size)
+        /// Optional sequence protocol operations
+        .def("__iter__", [](const Sequence &s) { return py::make_iterator(s.begin(), s.end()); },
+                         py::keep_alive<0, 1>() /* Essential: keep object alive while iterator exists */)
+        .def("__contains__", [](const Sequence &s, float v) { return s.contains(v); })
+        .def("__reversed__", [](const Sequence &s) -> Sequence { return s.reversed(); })
+        /// Slicing protocol (optional)
+        .def("__getitem__", [](const Sequence &s, py::slice slice) -> Sequence* {
             size_t start, stop, step, slicelength;
             if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
                 throw py::error_already_set();
             Sequence *seq = new Sequence(slicelength);
-            for (size_t i=0; i<slicelength; ++i) {
+            for (size_t i = 0; i < slicelength; ++i) {
                 (*seq)[i] = s[start]; start += step;
             }
             return seq;
         })
-       .def("__setitem__", [](Sequence &s, py::slice slice, const Sequence &value) {
+        .def("__setitem__", [](Sequence &s, py::slice slice, const Sequence &value) {
             size_t start, stop, step, slicelength;
             if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
                 throw py::error_already_set();
             if (slicelength != value.size())
                 throw std::runtime_error("Left and right hand size of slice assignment have different sizes!");
-            for (size_t i=0; i<slicelength; ++i) {
+            for (size_t i = 0; i < slicelength; ++i) {
                 s[start] = value[i]; start += step;
             }
         })
-       /// Comparisons
-       .def(py::self == py::self)
-       .def(py::self != py::self);
-       // Could also define py::self + py::self for concatenation, etc.
-
-    py::class_<StringMap> map(m, "StringMap");
+        /// Comparisons
+        .def(py::self == py::self)
+        .def(py::self != py::self)
+        // Could also define py::self + py::self for concatenation, etc.
+        ;
 
-    map .def(py::init<>())
+    // test_map_iterator
+    // Interface of a map-like object that isn't (directly) an unordered_map, but provides some basic
+    // map-like functionality.
+    class StringMap {
+    public:
+        StringMap() = default;
+        StringMap(std::unordered_map<std::string, std::string> init)
+            : map(std::move(init)) {}
+
+        void set(std::string key, std::string val) { map[key] = val; }
+        std::string get(std::string key) const { return map.at(key); }
+        size_t size() const { return map.size(); }
+    private:
+        std::unordered_map<std::string, std::string> map;
+    public:
+        decltype(map.cbegin()) begin() const { return map.cbegin(); }
+        decltype(map.cend()) end() const { return map.cend(); }
+    };
+    py::class_<StringMap>(m, "StringMap")
+        .def(py::init<>())
         .def(py::init<std::unordered_map<std::string, std::string>>())
         .def("__getitem__", [](const StringMap &map, std::string key) {
                 try { return map.get(key); }
                 catch (const std::out_of_range&) {
                     throw py::key_error("key '" + key + "' does not exist");
                 }
-                })
+        })
         .def("__setitem__", &StringMap::set)
         .def("__len__", &StringMap::size)
         .def("__iter__", [](const StringMap &map) { return py::make_key_iterator(map.begin(), map.end()); },
@@ -278,14 +236,23 @@ test_initializer sequences_and_iterators([](py::module &pm) {
                 py::keep_alive<0, 1>())
         ;
 
+    // test_generalized_iterators
+    class IntPairs {
+    public:
+        IntPairs(std::vector<std::pair<int, int>> data) : data_(std::move(data)) {}
+        const std::pair<int, int>* begin() const { return data_.data(); }
+    private:
+        std::vector<std::pair<int, int>> data_;
+    };
     py::class_<IntPairs>(m, "IntPairs")
         .def(py::init<std::vector<std::pair<int, int>>>())
         .def("nonzero", [](const IntPairs& s) {
                 return py::make_iterator(NonZeroIterator<std::pair<int, int>>(s.begin()), NonZeroSentinel());
-            }, py::keep_alive<0, 1>())
+        }, py::keep_alive<0, 1>())
         .def("nonzero_keys", [](const IntPairs& s) {
             return py::make_key_iterator(NonZeroIterator<std::pair<int, int>>(s.begin()), NonZeroSentinel());
-        }, py::keep_alive<0, 1>());
+        }, py::keep_alive<0, 1>())
+        ;
 
 
 #if 0
@@ -315,6 +282,7 @@ test_initializer sequences_and_iterators([](py::module &pm) {
     .def("__iter__", [](py::object s) { return PySequenceIterator(s.cast<const Sequence &>(), s); })
 #endif
 
+    // test_python_iterator_in_cpp
     m.def("object_to_list", [](py::object o) {
         auto l = py::list();
         for (auto item : o) {
@@ -348,7 +316,19 @@ test_initializer sequences_and_iterators([](py::module &pm) {
        });
     });
 
-    m.def("tuple_iterator", [](py::tuple x) { return test_random_access_iterator(x); });
-    m.def("list_iterator", [](py::list x) { return test_random_access_iterator(x); });
-    m.def("sequence_iterator", [](py::sequence x) { return test_random_access_iterator(x); });
-});
+    m.def("tuple_iterator", &test_random_access_iterator<py::tuple>);
+    m.def("list_iterator", &test_random_access_iterator<py::list>);
+    m.def("sequence_iterator", &test_random_access_iterator<py::sequence>);
+
+    // test_iterator_passthrough
+    // #181: iterator passthrough did not compile
+    m.def("iterator_passthrough", [](py::iterator s) -> py::iterator {
+        return py::make_iterator(std::begin(s), std::end(s));
+    });
+
+    // test_iterator_rvp
+    // #388: Can't make iterators via make_iterator() with different r/v policies
+    static std::vector<int> list = { 1, 2, 3 };
+    m.def("make_iterator_1", []() { return py::make_iterator<py::return_value_policy::copy>(list); });
+    m.def("make_iterator_2", []() { return py::make_iterator<py::return_value_policy::automatic>(list); });
+}
diff --git a/ext/pybind11/tests/test_sequences_and_iterators.py b/ext/pybind11/tests/test_sequences_and_iterators.py
index 30b6aaf4b..640ca07bd 100644
--- a/ext/pybind11/tests/test_sequences_and_iterators.py
+++ b/ext/pybind11/tests/test_sequences_and_iterators.py
@@ -1,4 +1,6 @@
 import pytest
+from pybind11_tests import sequences_and_iterators as m
+from pybind11_tests import ConstructorStats
 
 
 def isclose(a, b, rel_tol=1e-05, abs_tol=0.0):
@@ -11,24 +13,30 @@ def allclose(a_list, b_list, rel_tol=1e-05, abs_tol=0.0):
 
 
 def test_generalized_iterators():
-    from pybind11_tests.sequences_and_iterators import IntPairs
+    assert list(m.IntPairs([(1, 2), (3, 4), (0, 5)]).nonzero()) == [(1, 2), (3, 4)]
+    assert list(m.IntPairs([(1, 2), (2, 0), (0, 3), (4, 5)]).nonzero()) == [(1, 2)]
+    assert list(m.IntPairs([(0, 3), (1, 2), (3, 4)]).nonzero()) == []
 
-    assert list(IntPairs([(1, 2), (3, 4), (0, 5)]).nonzero()) == [(1, 2), (3, 4)]
-    assert list(IntPairs([(1, 2), (2, 0), (0, 3), (4, 5)]).nonzero()) == [(1, 2)]
-    assert list(IntPairs([(0, 3), (1, 2), (3, 4)]).nonzero()) == []
+    assert list(m.IntPairs([(1, 2), (3, 4), (0, 5)]).nonzero_keys()) == [1, 3]
+    assert list(m.IntPairs([(1, 2), (2, 0), (0, 3), (4, 5)]).nonzero_keys()) == [1]
+    assert list(m.IntPairs([(0, 3), (1, 2), (3, 4)]).nonzero_keys()) == []
 
-    assert list(IntPairs([(1, 2), (3, 4), (0, 5)]).nonzero_keys()) == [1, 3]
-    assert list(IntPairs([(1, 2), (2, 0), (0, 3), (4, 5)]).nonzero_keys()) == [1]
-    assert list(IntPairs([(0, 3), (1, 2), (3, 4)]).nonzero_keys()) == []
+    # __next__ must continue to raise StopIteration
+    it = m.IntPairs([(0, 0)]).nonzero()
+    for _ in range(3):
+        with pytest.raises(StopIteration):
+            next(it)
 
+    it = m.IntPairs([(0, 0)]).nonzero_keys()
+    for _ in range(3):
+        with pytest.raises(StopIteration):
+            next(it)
 
-def test_sequence():
-    from pybind11_tests import ConstructorStats
-    from pybind11_tests.sequences_and_iterators import Sequence
 
-    cstats = ConstructorStats.get(Sequence)
+def test_sequence():
+    cstats = ConstructorStats.get(m.Sequence)
 
-    s = Sequence(5)
+    s = m.Sequence(5)
     assert cstats.values() == ['of size', '5']
 
     assert "Sequence" in repr(s)
@@ -45,16 +53,24 @@ def test_sequence():
     rev2 = s[::-1]
     assert cstats.values() == ['of size', '5']
 
+    it = iter(m.Sequence(0))
+    for _ in range(3):  # __next__ must continue to raise StopIteration
+        with pytest.raises(StopIteration):
+            next(it)
+    assert cstats.values() == ['of size', '0']
+
     expected = [0, 56.78, 0, 0, 12.34]
     assert allclose(rev, expected)
     assert allclose(rev2, expected)
     assert rev == rev2
 
-    rev[0::2] = Sequence([2.0, 2.0, 2.0])
+    rev[0::2] = m.Sequence([2.0, 2.0, 2.0])
     assert cstats.values() == ['of size', '3', 'from std::vector']
 
     assert allclose(rev, [2, 56.78, 2, 0, 2])
 
+    assert cstats.alive() == 4
+    del it
     assert cstats.alive() == 3
     del s
     assert cstats.alive() == 2
@@ -72,28 +88,29 @@ def test_sequence():
 
 
 def test_map_iterator():
-    from pybind11_tests.sequences_and_iterators import StringMap
-
-    m = StringMap({'hi': 'bye', 'black': 'white'})
-    assert m['hi'] == 'bye'
-    assert len(m) == 2
-    assert m['black'] == 'white'
+    sm = m.StringMap({'hi': 'bye', 'black': 'white'})
+    assert sm['hi'] == 'bye'
+    assert len(sm) == 2
+    assert sm['black'] == 'white'
 
     with pytest.raises(KeyError):
-        assert m['orange']
-    m['orange'] = 'banana'
-    assert m['orange'] == 'banana'
+        assert sm['orange']
+    sm['orange'] = 'banana'
+    assert sm['orange'] == 'banana'
 
     expected = {'hi': 'bye', 'black': 'white', 'orange': 'banana'}
-    for k in m:
-        assert m[k] == expected[k]
-    for k, v in m.items():
+    for k in sm:
+        assert sm[k] == expected[k]
+    for k, v in sm.items():
         assert v == expected[k]
 
+    it = iter(m.StringMap({}))
+    for _ in range(3):  # __next__ must continue to raise StopIteration
+        with pytest.raises(StopIteration):
+            next(it)
 
-def test_python_iterator_in_cpp():
-    import pybind11_tests.sequences_and_iterators as m
 
+def test_python_iterator_in_cpp():
     t = (1, 2, 3)
     assert m.object_to_list(t) == [1, 2, 3]
     assert m.object_to_list(iter(t)) == [1, 2, 3]
@@ -123,3 +140,19 @@ def test_python_iterator_in_cpp():
     assert all(m.tuple_iterator(tuple(r)))
     assert all(m.list_iterator(list(r)))
     assert all(m.sequence_iterator(r))
+
+
+def test_iterator_passthrough():
+    """#181: iterator passthrough did not compile"""
+    from pybind11_tests.sequences_and_iterators import iterator_passthrough
+
+    assert list(iterator_passthrough(iter([3, 5, 7, 9, 11, 13, 15]))) == [3, 5, 7, 9, 11, 13, 15]
+
+
+def test_iterator_rvp():
+    """#388: Can't make iterators via make_iterator() with different r/v policies """
+    import pybind11_tests.sequences_and_iterators as m
+
+    assert list(m.make_iterator_1()) == [1, 2, 3]
+    assert list(m.make_iterator_2()) == [1, 2, 3]
+    assert not isinstance(m.make_iterator_1(), type(m.make_iterator_2()))
diff --git a/ext/pybind11/tests/test_smart_ptr.cpp b/ext/pybind11/tests/test_smart_ptr.cpp
index 83c1c018a..dccb1e9be 100644
--- a/ext/pybind11/tests/test_smart_ptr.cpp
+++ b/ext/pybind11/tests/test_smart_ptr.cpp
@@ -8,88 +8,19 @@
     BSD-style license that can be found in the LICENSE file.
 */
 
+#if defined(_MSC_VER) && _MSC_VER < 1910
+#  pragma warning(disable: 4702) // unreachable code in system header
+#endif
+
 #include "pybind11_tests.h"
 #include "object.h"
 
-/// Custom object with builtin reference counting (see 'object.h' for the implementation)
-class MyObject1 : public Object {
-public:
-    MyObject1(int value) : value(value) {
-        print_created(this, toString());
-    }
-
-    std::string toString() const {
-        return "MyObject1[" + std::to_string(value) + "]";
-    }
-
-protected:
-    virtual ~MyObject1() {
-        print_destroyed(this);
-    }
-
-private:
-    int value;
-};
-
-/// Object managed by a std::shared_ptr<>
-class MyObject2 {
-public:
-    MyObject2(int value) : value(value) {
-        print_created(this, toString());
-    }
-
-    std::string toString() const {
-        return "MyObject2[" + std::to_string(value) + "]";
-    }
-
-    virtual ~MyObject2() {
-        print_destroyed(this);
-    }
-
-private:
-    int value;
-};
-
-/// Object managed by a std::shared_ptr<>, additionally derives from std::enable_shared_from_this<>
-class MyObject3 : public std::enable_shared_from_this<MyObject3> {
-public:
-    MyObject3(int value) : value(value) {
-        print_created(this, toString());
-    }
-
-    std::string toString() const {
-        return "MyObject3[" + std::to_string(value) + "]";
-    }
-
-    virtual ~MyObject3() {
-        print_destroyed(this);
-    }
-
-private:
-    int value;
-};
-
-class MyObject4 {
-public:
-    MyObject4(int value) : value{value} {
-        print_created(this);
-    }
-    int value;
-private:
-    ~MyObject4() {
-        print_destroyed(this);
-    }
-};
-
-/// Make pybind aware of the ref-counted wrapper type (s)
+// Make pybind aware of the ref-counted wrapper type (s):
 
 // ref<T> is a wrapper for 'Object' which uses intrusive reference counting
 // It is always possible to construct a ref<T> from an Object* pointer without
 // possible incosistencies, hence the 'true' argument at the end.
 PYBIND11_DECLARE_HOLDER_TYPE(T, ref<T>, true);
-PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>); // Not required any more for std::shared_ptr,
-                                                     // but it should compile without error
-
 // Make pybind11 aware of the non-standard getter member function
 namespace pybind11 { namespace detail {
     template <typename T>
@@ -98,140 +29,157 @@ namespace pybind11 { namespace detail {
     };
 }}
 
-Object *make_object_1() { return new MyObject1(1); }
-ref<Object> make_object_2() { return new MyObject1(2); }
-
-MyObject1 *make_myobject1_1() { return new MyObject1(4); }
-ref<MyObject1> make_myobject1_2() { return new MyObject1(5); }
-
-MyObject2 *make_myobject2_1() { return new MyObject2(6); }
-std::shared_ptr<MyObject2> make_myobject2_2() { return std::make_shared<MyObject2>(7); }
+// The following is not required anymore for std::shared_ptr, but it should compile without error:
+PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>);
 
-MyObject3 *make_myobject3_1() { return new MyObject3(8); }
-std::shared_ptr<MyObject3> make_myobject3_2() { return std::make_shared<MyObject3>(9); }
+// This is just a wrapper around unique_ptr, but with extra fields to deliberately bloat up the
+// holder size to trigger the non-simple-layout internal instance layout for single inheritance with
+// large holder type:
+template <typename T> class huge_unique_ptr {
+    std::unique_ptr<T> ptr;
+    uint64_t padding[10];
+public:
+    huge_unique_ptr(T *p) : ptr(p) {};
+    T *get() { return ptr.get(); }
+};
+PYBIND11_DECLARE_HOLDER_TYPE(T, huge_unique_ptr<T>);
 
-void print_object_1(const Object *obj) { py::print(obj->toString()); }
-void print_object_2(ref<Object> obj) { py::print(obj->toString()); }
-void print_object_3(const ref<Object> &obj) { py::print(obj->toString()); }
-void print_object_4(const ref<Object> *obj) { py::print((*obj)->toString()); }
+// Simple custom holder that works like unique_ptr
+template <typename T>
+class custom_unique_ptr {
+    std::unique_ptr<T> impl;
+public:
+    custom_unique_ptr(T* p) : impl(p) { }
+    T* get() const { return impl.get(); }
+    T* release_ptr() { return impl.release(); }
+};
+PYBIND11_DECLARE_HOLDER_TYPE(T, custom_unique_ptr<T>);
 
-void print_myobject1_1(const MyObject1 *obj) { py::print(obj->toString()); }
-void print_myobject1_2(ref<MyObject1> obj) { py::print(obj->toString()); }
-void print_myobject1_3(const ref<MyObject1> &obj) { py::print(obj->toString()); }
-void print_myobject1_4(const ref<MyObject1> *obj) { py::print((*obj)->toString()); }
 
-void print_myobject2_1(const MyObject2 *obj) { py::print(obj->toString()); }
-void print_myobject2_2(std::shared_ptr<MyObject2> obj) { py::print(obj->toString()); }
-void print_myobject2_3(const std::shared_ptr<MyObject2> &obj) { py::print(obj->toString()); }
-void print_myobject2_4(const std::shared_ptr<MyObject2> *obj) { py::print((*obj)->toString()); }
+TEST_SUBMODULE(smart_ptr, m) {
 
-void print_myobject3_1(const MyObject3 *obj) { py::print(obj->toString()); }
-void print_myobject3_2(std::shared_ptr<MyObject3> obj) { py::print(obj->toString()); }
-void print_myobject3_3(const std::shared_ptr<MyObject3> &obj) { py::print(obj->toString()); }
-void print_myobject3_4(const std::shared_ptr<MyObject3> *obj) { py::print((*obj)->toString()); }
+    // test_smart_ptr
 
-test_initializer smart_ptr([](py::module &m) {
+    // Object implementation in `object.h`
     py::class_<Object, ref<Object>> obj(m, "Object");
     obj.def("getRefCount", &Object::getRefCount);
 
+    // Custom object with builtin reference counting (see 'object.h' for the implementation)
+    class MyObject1 : public Object {
+    public:
+        MyObject1(int value) : value(value) { print_created(this, toString()); }
+        std::string toString() const { return "MyObject1[" + std::to_string(value) + "]"; }
+    protected:
+        virtual ~MyObject1() { print_destroyed(this); }
+    private:
+        int value;
+    };
     py::class_<MyObject1, ref<MyObject1>>(m, "MyObject1", obj)
         .def(py::init<int>());
+    py::implicitly_convertible<py::int_, MyObject1>();
 
-    m.def("test_object1_refcounting",
-        []() -> bool {
-            ref<MyObject1> o = new MyObject1(0);
-            bool good = o->getRefCount() == 1;
-            py::object o2 = py::cast(o, py::return_value_policy::reference);
-            // always request (partial) ownership for objects with intrusive
-            // reference counting even when using the 'reference' RVP
-            good &= o->getRefCount() == 2;
-            return good;
-        }
-    );
-
-    m.def("make_object_1", &make_object_1);
-    m.def("make_object_2", &make_object_2);
-    m.def("make_myobject1_1", &make_myobject1_1);
-    m.def("make_myobject1_2", &make_myobject1_2);
-    m.def("print_object_1", &print_object_1);
-    m.def("print_object_2", &print_object_2);
-    m.def("print_object_3", &print_object_3);
-    m.def("print_object_4", &print_object_4);
-    m.def("print_myobject1_1", &print_myobject1_1);
-    m.def("print_myobject1_2", &print_myobject1_2);
-    m.def("print_myobject1_3", &print_myobject1_3);
-    m.def("print_myobject1_4", &print_myobject1_4);
+    m.def("make_object_1", []() -> Object * { return new MyObject1(1); });
+    m.def("make_object_2", []() -> ref<Object> { return new MyObject1(2); });
+    m.def("make_myobject1_1", []() -> MyObject1 * { return new MyObject1(4); });
+    m.def("make_myobject1_2", []() -> ref<MyObject1> { return new MyObject1(5); });
+    m.def("print_object_1", [](const Object *obj) { py::print(obj->toString()); });
+    m.def("print_object_2", [](ref<Object> obj) { py::print(obj->toString()); });
+    m.def("print_object_3", [](const ref<Object> &obj) { py::print(obj->toString()); });
+    m.def("print_object_4", [](const ref<Object> *obj) { py::print((*obj)->toString()); });
+    m.def("print_myobject1_1", [](const MyObject1 *obj) { py::print(obj->toString()); });
+    m.def("print_myobject1_2", [](ref<MyObject1> obj) { py::print(obj->toString()); });
+    m.def("print_myobject1_3", [](const ref<MyObject1> &obj) { py::print(obj->toString()); });
+    m.def("print_myobject1_4", [](const ref<MyObject1> *obj) { py::print((*obj)->toString()); });
 
+    // Expose constructor stats for the ref type
+    m.def("cstats_ref", &ConstructorStats::get<ref_tag>);
+
+
+    // Object managed by a std::shared_ptr<>
+    class MyObject2 {
+    public:
+        MyObject2(int value) : value(value) { print_created(this, toString()); }
+        std::string toString() const { return "MyObject2[" + std::to_string(value) + "]"; }
+        virtual ~MyObject2() { print_destroyed(this); }
+    private:
+        int value;
+    };
     py::class_<MyObject2, std::shared_ptr<MyObject2>>(m, "MyObject2")
         .def(py::init<int>());
-    m.def("make_myobject2_1", &make_myobject2_1);
-    m.def("make_myobject2_2", &make_myobject2_2);
-    m.def("print_myobject2_1", &print_myobject2_1);
-    m.def("print_myobject2_2", &print_myobject2_2);
-    m.def("print_myobject2_3", &print_myobject2_3);
-    m.def("print_myobject2_4", &print_myobject2_4);
-
+    m.def("make_myobject2_1", []() { return new MyObject2(6); });
+    m.def("make_myobject2_2", []() { return std::make_shared<MyObject2>(7); });
+    m.def("print_myobject2_1", [](const MyObject2 *obj) { py::print(obj->toString()); });
+    m.def("print_myobject2_2", [](std::shared_ptr<MyObject2> obj) { py::print(obj->toString()); });
+    m.def("print_myobject2_3", [](const std::shared_ptr<MyObject2> &obj) { py::print(obj->toString()); });
+    m.def("print_myobject2_4", [](const std::shared_ptr<MyObject2> *obj) { py::print((*obj)->toString()); });
+
+    // Object managed by a std::shared_ptr<>, additionally derives from std::enable_shared_from_this<>
+    class MyObject3 : public std::enable_shared_from_this<MyObject3> {
+    public:
+        MyObject3(int value) : value(value) { print_created(this, toString()); }
+        std::string toString() const { return "MyObject3[" + std::to_string(value) + "]"; }
+        virtual ~MyObject3() { print_destroyed(this); }
+    private:
+        int value;
+    };
     py::class_<MyObject3, std::shared_ptr<MyObject3>>(m, "MyObject3")
         .def(py::init<int>());
-    m.def("make_myobject3_1", &make_myobject3_1);
-    m.def("make_myobject3_2", &make_myobject3_2);
-    m.def("print_myobject3_1", &print_myobject3_1);
-    m.def("print_myobject3_2", &print_myobject3_2);
-    m.def("print_myobject3_3", &print_myobject3_3);
-    m.def("print_myobject3_4", &print_myobject3_4);
-
+    m.def("make_myobject3_1", []() { return new MyObject3(8); });
+    m.def("make_myobject3_2", []() { return std::make_shared<MyObject3>(9); });
+    m.def("print_myobject3_1", [](const MyObject3 *obj) { py::print(obj->toString()); });
+    m.def("print_myobject3_2", [](std::shared_ptr<MyObject3> obj) { py::print(obj->toString()); });
+    m.def("print_myobject3_3", [](const std::shared_ptr<MyObject3> &obj) { py::print(obj->toString()); });
+    m.def("print_myobject3_4", [](const std::shared_ptr<MyObject3> *obj) { py::print((*obj)->toString()); });
+
+    // test_smart_ptr_refcounting
+    m.def("test_object1_refcounting", []() {
+        ref<MyObject1> o = new MyObject1(0);
+        bool good = o->getRefCount() == 1;
+        py::object o2 = py::cast(o, py::return_value_policy::reference);
+        // always request (partial) ownership for objects with intrusive
+        // reference counting even when using the 'reference' RVP
+        good &= o->getRefCount() == 2;
+        return good;
+    });
+
+    // test_unique_nodelete
+    // Object with a private destructor
+    class MyObject4 {
+    public:
+        MyObject4(int value) : value{value} { print_created(this); }
+        int value;
+    private:
+        ~MyObject4() { print_destroyed(this); }
+    };
     py::class_<MyObject4, std::unique_ptr<MyObject4, py::nodelete>>(m, "MyObject4")
         .def(py::init<int>())
         .def_readwrite("value", &MyObject4::value);
 
-    py::implicitly_convertible<py::int_, MyObject1>();
-
-    // Expose constructor stats for the ref type
-    m.def("cstats_ref", &ConstructorStats::get<ref_tag>);
-});
-
-struct SharedPtrRef {
-    struct A {
-        A() { print_created(this); }
-        A(const A &) { print_copy_created(this); }
-        A(A &&) { print_move_created(this); }
-        ~A() { print_destroyed(this); }
+    // test_large_holder
+    class MyObject5 { // managed by huge_unique_ptr
+    public:
+        MyObject5(int value) : value{value} { print_created(this); }
+        ~MyObject5() { print_destroyed(this); }
+        int value;
     };
-
-    A value = {};
-    std::shared_ptr<A> shared = std::make_shared<A>();
-};
-
-struct SharedFromThisRef {
-    struct B : std::enable_shared_from_this<B> {
-        B() { print_created(this); }
-        B(const B &) : std::enable_shared_from_this<B>() { print_copy_created(this); }
-        B(B &&) : std::enable_shared_from_this<B>() { print_move_created(this); }
-        ~B() { print_destroyed(this); }
+    py::class_<MyObject5, huge_unique_ptr<MyObject5>>(m, "MyObject5")
+        .def(py::init<int>())
+        .def_readwrite("value", &MyObject5::value);
+
+    // test_shared_ptr_and_references
+    struct SharedPtrRef {
+        struct A {
+            A() { print_created(this); }
+            A(const A &) { print_copy_created(this); }
+            A(A &&) { print_move_created(this); }
+            ~A() { print_destroyed(this); }
+        };
+
+        A value = {};
+        std::shared_ptr<A> shared = std::make_shared<A>();
     };
-
-    B value = {};
-    std::shared_ptr<B> shared = std::make_shared<B>();
-};
-
-template <typename T>
-class CustomUniquePtr {
-    std::unique_ptr<T> impl;
-
-public:
-    CustomUniquePtr(T* p) : impl(p) { }
-    T* get() const { return impl.get(); }
-    T* release_ptr() { return impl.release(); }
-};
-
-PYBIND11_DECLARE_HOLDER_TYPE(T, CustomUniquePtr<T>);
-
-test_initializer smart_ptr_and_references([](py::module &pm) {
-    auto m = pm.def_submodule("smart_ptr");
-
     using A = SharedPtrRef::A;
     py::class_<A, std::shared_ptr<A>>(m, "A");
-
     py::class_<SharedPtrRef>(m, "SharedPtrRef")
         .def(py::init<>())
         .def_readonly("ref", &SharedPtrRef::value)
@@ -243,9 +191,20 @@ test_initializer smart_ptr_and_references([](py::module &pm) {
         .def("set_ref", [](SharedPtrRef &, const A &) { return true; })
         .def("set_holder", [](SharedPtrRef &, std::shared_ptr<A>) { return true; });
 
+    // test_shared_ptr_from_this_and_references
+    struct SharedFromThisRef {
+        struct B : std::enable_shared_from_this<B> {
+            B() { print_created(this); }
+            B(const B &) : std::enable_shared_from_this<B>() { print_copy_created(this); }
+            B(B &&) : std::enable_shared_from_this<B>() { print_move_created(this); }
+            ~B() { print_destroyed(this); }
+        };
+
+        B value = {};
+        std::shared_ptr<B> shared = std::make_shared<B>();
+    };
     using B = SharedFromThisRef::B;
     py::class_<B, std::shared_ptr<B>>(m, "B");
-
     py::class_<SharedFromThisRef>(m, "SharedFromThisRef")
         .def(py::init<>())
         .def_readonly("bad_wp", &SharedFromThisRef::value)
@@ -258,17 +217,54 @@ test_initializer smart_ptr_and_references([](py::module &pm) {
         .def("set_ref", [](SharedFromThisRef &, const B &) { return true; })
         .def("set_holder", [](SharedFromThisRef &, std::shared_ptr<B>) { return true; });
 
+    // Issue #865: shared_from_this doesn't work with virtual inheritance
+    struct SharedFromThisVBase : std::enable_shared_from_this<SharedFromThisVBase> {
+        virtual ~SharedFromThisVBase() = default;
+    };
+    struct SharedFromThisVirt : virtual SharedFromThisVBase {};
+    static std::shared_ptr<SharedFromThisVirt> sft(new SharedFromThisVirt());
+    py::class_<SharedFromThisVirt, std::shared_ptr<SharedFromThisVirt>>(m, "SharedFromThisVirt")
+        .def_static("get", []() { return sft.get(); });
+
+    // test_move_only_holder
     struct C {
         C() { print_created(this); }
         ~C() { print_destroyed(this); }
     };
+    py::class_<C, custom_unique_ptr<C>>(m, "TypeWithMoveOnlyHolder")
+        .def_static("make", []() { return custom_unique_ptr<C>(new C); });
 
-    py::class_<C, CustomUniquePtr<C>>(m, "TypeWithMoveOnlyHolder")
-        .def_static("make", []() { return CustomUniquePtr<C>(new C); });
-
+    // test_smart_ptr_from_default
     struct HeldByDefaultHolder { };
-
     py::class_<HeldByDefaultHolder>(m, "HeldByDefaultHolder")
         .def(py::init<>())
         .def_static("load_shared_ptr", [](std::shared_ptr<HeldByDefaultHolder>) {});
-});
+
+    // test_shared_ptr_gc
+    // #187: issue involving std::shared_ptr<> return value policy & garbage collection
+    struct ElementBase { virtual void foo() { } /* Force creation of virtual table */ };
+    py::class_<ElementBase, std::shared_ptr<ElementBase>>(m, "ElementBase");
+
+    struct ElementA : ElementBase {
+        ElementA(int v) : v(v) { }
+        int value() { return v; }
+        int v;
+    };
+    py::class_<ElementA, ElementBase, std::shared_ptr<ElementA>>(m, "ElementA")
+        .def(py::init<int>())
+        .def("value", &ElementA::value);
+
+    struct ElementList {
+        void add(std::shared_ptr<ElementBase> e) { l.push_back(e); }
+        std::vector<std::shared_ptr<ElementBase>> l;
+    };
+    py::class_<ElementList, std::shared_ptr<ElementList>>(m, "ElementList")
+        .def(py::init<>())
+        .def("add", &ElementList::add)
+        .def("get", [](ElementList &el) {
+            py::list list;
+            for (auto &e : el.l)
+                list.append(py::cast(e));
+            return list;
+        });
+}
diff --git a/ext/pybind11/tests/test_smart_ptr.py b/ext/pybind11/tests/test_smart_ptr.py
index b5af3bd38..4dfe0036f 100644
--- a/ext/pybind11/tests/test_smart_ptr.py
+++ b/ext/pybind11/tests/test_smart_ptr.py
@@ -1,40 +1,35 @@
 import pytest
+from pybind11_tests import smart_ptr as m
 from pybind11_tests import ConstructorStats
 
 
 def test_smart_ptr(capture):
     # Object1
-    from pybind11_tests import (MyObject1, make_object_1, make_object_2,
-                                print_object_1, print_object_2, print_object_3, print_object_4)
-
-    for i, o in enumerate([make_object_1(), make_object_2(), MyObject1(3)], start=1):
+    for i, o in enumerate([m.make_object_1(), m.make_object_2(), m.MyObject1(3)], start=1):
         assert o.getRefCount() == 1
         with capture:
-            print_object_1(o)
-            print_object_2(o)
-            print_object_3(o)
-            print_object_4(o)
+            m.print_object_1(o)
+            m.print_object_2(o)
+            m.print_object_3(o)
+            m.print_object_4(o)
         assert capture == "MyObject1[{i}]\n".format(i=i) * 4
 
-    from pybind11_tests import (make_myobject1_1, make_myobject1_2,
-                                print_myobject1_1, print_myobject1_2,
-                                print_myobject1_3, print_myobject1_4)
-
-    for i, o in enumerate([make_myobject1_1(), make_myobject1_2(), MyObject1(6), 7], start=4):
+    for i, o in enumerate([m.make_myobject1_1(), m.make_myobject1_2(), m.MyObject1(6), 7],
+                          start=4):
         print(o)
         with capture:
             if not isinstance(o, int):
-                print_object_1(o)
-                print_object_2(o)
-                print_object_3(o)
-                print_object_4(o)
-            print_myobject1_1(o)
-            print_myobject1_2(o)
-            print_myobject1_3(o)
-            print_myobject1_4(o)
+                m.print_object_1(o)
+                m.print_object_2(o)
+                m.print_object_3(o)
+                m.print_object_4(o)
+            m.print_myobject1_1(o)
+            m.print_myobject1_2(o)
+            m.print_myobject1_3(o)
+            m.print_myobject1_4(o)
         assert capture == "MyObject1[{i}]\n".format(i=i) * (4 if isinstance(o, int) else 8)
 
-    cstats = ConstructorStats.get(MyObject1)
+    cstats = ConstructorStats.get(m.MyObject1)
     assert cstats.alive() == 0
     expected_values = ['MyObject1[{}]'.format(i) for i in range(1, 7)] + ['MyObject1[7]'] * 4
     assert cstats.values() == expected_values
@@ -45,21 +40,16 @@ def test_smart_ptr(capture):
     assert cstats.move_assignments == 0
 
     # Object2
-    from pybind11_tests import (MyObject2, make_myobject2_1, make_myobject2_2,
-                                make_myobject3_1, make_myobject3_2,
-                                print_myobject2_1, print_myobject2_2,
-                                print_myobject2_3, print_myobject2_4)
-
-    for i, o in zip([8, 6, 7], [MyObject2(8), make_myobject2_1(), make_myobject2_2()]):
+    for i, o in zip([8, 6, 7], [m.MyObject2(8), m.make_myobject2_1(), m.make_myobject2_2()]):
         print(o)
         with capture:
-            print_myobject2_1(o)
-            print_myobject2_2(o)
-            print_myobject2_3(o)
-            print_myobject2_4(o)
+            m.print_myobject2_1(o)
+            m.print_myobject2_2(o)
+            m.print_myobject2_3(o)
+            m.print_myobject2_4(o)
         assert capture == "MyObject2[{i}]\n".format(i=i) * 4
 
-    cstats = ConstructorStats.get(MyObject2)
+    cstats = ConstructorStats.get(m.MyObject2)
     assert cstats.alive() == 1
     o = None
     assert cstats.alive() == 0
@@ -71,19 +61,16 @@ def test_smart_ptr(capture):
     assert cstats.move_assignments == 0
 
     # Object3
-    from pybind11_tests import (MyObject3, print_myobject3_1, print_myobject3_2,
-                                print_myobject3_3, print_myobject3_4)
-
-    for i, o in zip([9, 8, 9], [MyObject3(9), make_myobject3_1(), make_myobject3_2()]):
+    for i, o in zip([9, 8, 9], [m.MyObject3(9), m.make_myobject3_1(), m.make_myobject3_2()]):
         print(o)
         with capture:
-            print_myobject3_1(o)
-            print_myobject3_2(o)
-            print_myobject3_3(o)
-            print_myobject3_4(o)
+            m.print_myobject3_1(o)
+            m.print_myobject3_2(o)
+            m.print_myobject3_3(o)
+            m.print_myobject3_4(o)
         assert capture == "MyObject3[{i}]\n".format(i=i) * 4
 
-    cstats = ConstructorStats.get(MyObject3)
+    cstats = ConstructorStats.get(m.MyObject3)
     assert cstats.alive() == 1
     o = None
     assert cstats.alive() == 0
@@ -94,10 +81,8 @@ def test_smart_ptr(capture):
     assert cstats.copy_assignments == 0
     assert cstats.move_assignments == 0
 
-    # Object and ref
-    from pybind11_tests import Object, cstats_ref
-
-    cstats = ConstructorStats.get(Object)
+    # Object
+    cstats = ConstructorStats.get(m.Object)
     assert cstats.alive() == 0
     assert cstats.values() == []
     assert cstats.default_constructions == 10
@@ -106,7 +91,8 @@ def test_smart_ptr(capture):
     assert cstats.copy_assignments == 0
     assert cstats.move_assignments == 0
 
-    cstats = cstats_ref()
+    # ref<>
+    cstats = m.cstats_ref()
     assert cstats.alive() == 0
     assert cstats.values() == ['from pointer'] * 10
     assert cstats.default_constructions == 30
@@ -117,26 +103,30 @@ def test_smart_ptr(capture):
 
 
 def test_smart_ptr_refcounting():
-    from pybind11_tests import test_object1_refcounting
-    assert test_object1_refcounting()
+    assert m.test_object1_refcounting()
 
 
 def test_unique_nodelete():
-    from pybind11_tests import MyObject4
-    o = MyObject4(23)
+    o = m.MyObject4(23)
     assert o.value == 23
-    cstats = ConstructorStats.get(MyObject4)
+    cstats = ConstructorStats.get(m.MyObject4)
     assert cstats.alive() == 1
     del o
-    cstats = ConstructorStats.get(MyObject4)
     assert cstats.alive() == 1  # Leak, but that's intentional
 
 
-def test_shared_ptr_and_references():
-    from pybind11_tests.smart_ptr import SharedPtrRef, A
+def test_large_holder():
+    o = m.MyObject5(5)
+    assert o.value == 5
+    cstats = ConstructorStats.get(m.MyObject5)
+    assert cstats.alive() == 1
+    del o
+    assert cstats.alive() == 0
 
-    s = SharedPtrRef()
-    stats = ConstructorStats.get(A)
+
+def test_shared_ptr_and_references():
+    s = m.SharedPtrRef()
+    stats = ConstructorStats.get(m.A)
     assert stats.alive() == 2
 
     ref = s.ref  # init_holder_helper(holder_ptr=false, owned=false)
@@ -166,10 +156,8 @@ def test_shared_ptr_and_references():
 
 
 def test_shared_ptr_from_this_and_references():
-    from pybind11_tests.smart_ptr import SharedFromThisRef, B
-
-    s = SharedFromThisRef()
-    stats = ConstructorStats.get(B)
+    s = m.SharedFromThisRef()
+    stats = ConstructorStats.get(m.B)
     assert stats.alive() == 2
 
     ref = s.ref  # init_holder_helper(holder_ptr=false, owned=false, bad_wp=false)
@@ -202,21 +190,31 @@ def test_shared_ptr_from_this_and_references():
     del ref, bad_wp, copy, holder_ref, holder_copy, s
     assert stats.alive() == 0
 
+    z = m.SharedFromThisVirt.get()
+    y = m.SharedFromThisVirt.get()
+    assert y is z
 
-def test_move_only_holder():
-    from pybind11_tests.smart_ptr import TypeWithMoveOnlyHolder
 
-    a = TypeWithMoveOnlyHolder.make()
-    stats = ConstructorStats.get(TypeWithMoveOnlyHolder)
+def test_move_only_holder():
+    a = m.TypeWithMoveOnlyHolder.make()
+    stats = ConstructorStats.get(m.TypeWithMoveOnlyHolder)
     assert stats.alive() == 1
     del a
     assert stats.alive() == 0
 
 
 def test_smart_ptr_from_default():
-    from pybind11_tests.smart_ptr import HeldByDefaultHolder
-
-    instance = HeldByDefaultHolder()
+    instance = m.HeldByDefaultHolder()
     with pytest.raises(RuntimeError) as excinfo:
-        HeldByDefaultHolder.load_shared_ptr(instance)
+        m.HeldByDefaultHolder.load_shared_ptr(instance)
     assert "Unable to load a custom holder type from a default-holder instance" in str(excinfo)
+
+
+def test_shared_ptr_gc():
+    """#187: issue involving std::shared_ptr<> return value policy & garbage collection"""
+    el = m.ElementList()
+    for i in range(10):
+        el.add(m.ElementA(i))
+    pytest.gc_collect()
+    for i, v in enumerate(el.get()):
+        assert i == v.value()
diff --git a/ext/pybind11/tests/test_stl.cpp b/ext/pybind11/tests/test_stl.cpp
new file mode 100644
index 000000000..7d53e9c18
--- /dev/null
+++ b/ext/pybind11/tests/test_stl.cpp
@@ -0,0 +1,238 @@
+/*
+    tests/test_stl.cpp -- STL type casters
+
+    Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+#include <pybind11/stl.h>
+
+// Test with `std::variant` in C++17 mode, or with `boost::variant` in C++11/14
+#if PYBIND11_HAS_VARIANT
+using std::variant;
+#elif defined(PYBIND11_TEST_BOOST) && (!defined(_MSC_VER) || _MSC_VER >= 1910)
+#  include <boost/variant.hpp>
+#  define PYBIND11_HAS_VARIANT 1
+using boost::variant;
+
+namespace pybind11 { namespace detail {
+template <typename... Ts>
+struct type_caster<boost::variant<Ts...>> : variant_caster<boost::variant<Ts...>> {};
+
+template <>
+struct visit_helper<boost::variant> {
+    template <typename... Args>
+    static auto call(Args &&...args) -> decltype(boost::apply_visitor(args...)) {
+        return boost::apply_visitor(args...);
+    }
+};
+}} // namespace pybind11::detail
+#endif
+
+/// Issue #528: templated constructor
+struct TplCtorClass {
+    template <typename T> TplCtorClass(const T &) { }
+    bool operator==(const TplCtorClass &) const { return true; }
+};
+
+namespace std {
+    template <>
+    struct hash<TplCtorClass> { size_t operator()(const TplCtorClass &) const { return 0; } };
+}
+
+
+TEST_SUBMODULE(stl, m) {
+    // test_vector
+    m.def("cast_vector", []() { return std::vector<int>{1}; });
+    m.def("load_vector", [](const std::vector<int> &v) { return v.at(0) == 1 && v.at(1) == 2; });
+    // `std::vector<bool>` is special because it returns proxy objects instead of references
+    m.def("cast_bool_vector", []() { return std::vector<bool>{true, false}; });
+    m.def("load_bool_vector", [](const std::vector<bool> &v) {
+        return v.at(0) == true && v.at(1) == false;
+    });
+    // Unnumbered regression (caused by #936): pointers to stl containers aren't castable
+    static std::vector<RValueCaster> lvv{2};
+    m.def("cast_ptr_vector", []() { return &lvv; });
+
+    // test_array
+    m.def("cast_array", []() { return std::array<int, 2> {{1 , 2}}; });
+    m.def("load_array", [](const std::array<int, 2> &a) { return a[0] == 1 && a[1] == 2; });
+
+    // test_valarray
+    m.def("cast_valarray", []() { return std::valarray<int>{1, 4, 9}; });
+    m.def("load_valarray", [](const std::valarray<int>& v) {
+        return v.size() == 3 && v[0] == 1 && v[1] == 4 && v[2] == 9;
+    });
+
+    // test_map
+    m.def("cast_map", []() { return std::map<std::string, std::string>{{"key", "value"}}; });
+    m.def("load_map", [](const std::map<std::string, std::string> &map) {
+        return map.at("key") == "value" && map.at("key2") == "value2";
+    });
+
+    // test_set
+    m.def("cast_set", []() { return std::set<std::string>{"key1", "key2"}; });
+    m.def("load_set", [](const std::set<std::string> &set) {
+        return set.count("key1") && set.count("key2") && set.count("key3");
+    });
+
+    // test_recursive_casting
+    m.def("cast_rv_vector", []() { return std::vector<RValueCaster>{2}; });
+    m.def("cast_rv_array", []() { return std::array<RValueCaster, 3>(); });
+    // NB: map and set keys are `const`, so while we technically do move them (as `const Type &&`),
+    // casters don't typically do anything with that, which means they fall to the `const Type &`
+    // caster.
+    m.def("cast_rv_map", []() { return std::unordered_map<std::string, RValueCaster>{{"a", RValueCaster{}}}; });
+    m.def("cast_rv_nested", []() {
+        std::vector<std::array<std::list<std::unordered_map<std::string, RValueCaster>>, 2>> v;
+        v.emplace_back(); // add an array
+        v.back()[0].emplace_back(); // add a map to the array
+        v.back()[0].back().emplace("b", RValueCaster{});
+        v.back()[0].back().emplace("c", RValueCaster{});
+        v.back()[1].emplace_back(); // add a map to the array
+        v.back()[1].back().emplace("a", RValueCaster{});
+        return v;
+    });
+    static std::array<RValueCaster, 2> lva;
+    static std::unordered_map<std::string, RValueCaster> lvm{{"a", RValueCaster{}}, {"b", RValueCaster{}}};
+    static std::unordered_map<std::string, std::vector<std::list<std::array<RValueCaster, 2>>>> lvn;
+    lvn["a"].emplace_back(); // add a list
+    lvn["a"].back().emplace_back(); // add an array
+    lvn["a"].emplace_back(); // another list
+    lvn["a"].back().emplace_back(); // add an array
+    lvn["b"].emplace_back(); // add a list
+    lvn["b"].back().emplace_back(); // add an array
+    lvn["b"].back().emplace_back(); // add another array
+    m.def("cast_lv_vector", []() -> const decltype(lvv) & { return lvv; });
+    m.def("cast_lv_array", []() -> const decltype(lva) & { return lva; });
+    m.def("cast_lv_map", []() -> const decltype(lvm) & { return lvm; });
+    m.def("cast_lv_nested", []() -> const decltype(lvn) & { return lvn; });
+    // #853:
+    m.def("cast_unique_ptr_vector", []() {
+        std::vector<std::unique_ptr<UserType>> v;
+        v.emplace_back(new UserType{7});
+        v.emplace_back(new UserType{42});
+        return v;
+    });
+
+    // test_move_out_container
+    struct MoveOutContainer {
+        struct Value { int value; };
+        std::list<Value> move_list() const { return {{0}, {1}, {2}}; }
+    };
+    py::class_<MoveOutContainer::Value>(m, "MoveOutContainerValue")
+        .def_readonly("value", &MoveOutContainer::Value::value);
+    py::class_<MoveOutContainer>(m, "MoveOutContainer")
+        .def(py::init<>())
+        .def_property_readonly("move_list", &MoveOutContainer::move_list);
+
+    // Class that can be move- and copy-constructed, but not assigned
+    struct NoAssign {
+        int value;
+
+        explicit NoAssign(int value = 0) : value(value) { }
+        NoAssign(const NoAssign &) = default;
+        NoAssign(NoAssign &&) = default;
+
+        NoAssign &operator=(const NoAssign &) = delete;
+        NoAssign &operator=(NoAssign &&) = delete;
+    };
+    py::class_<NoAssign>(m, "NoAssign", "Class with no C++ assignment operators")
+        .def(py::init<>())
+        .def(py::init<int>());
+
+#ifdef PYBIND11_HAS_OPTIONAL
+    // test_optional
+    m.attr("has_optional") = true;
+
+    using opt_int = std::optional<int>;
+    using opt_no_assign = std::optional<NoAssign>;
+    m.def("double_or_zero", [](const opt_int& x) -> int {
+        return x.value_or(0) * 2;
+    });
+    m.def("half_or_none", [](int x) -> opt_int {
+        return x ? opt_int(x / 2) : opt_int();
+    });
+    m.def("test_nullopt", [](opt_int x) {
+        return x.value_or(42);
+    }, py::arg_v("x", std::nullopt, "None"));
+    m.def("test_no_assign", [](const opt_no_assign &x) {
+        return x ? x->value : 42;
+    }, py::arg_v("x", std::nullopt, "None"));
+
+    m.def("nodefer_none_optional", [](std::optional<int>) { return true; });
+    m.def("nodefer_none_optional", [](py::none) { return false; });
+#endif
+
+#ifdef PYBIND11_HAS_EXP_OPTIONAL
+    // test_exp_optional
+    m.attr("has_exp_optional") = true;
+
+    using exp_opt_int = std::experimental::optional<int>;
+    using exp_opt_no_assign = std::experimental::optional<NoAssign>;
+    m.def("double_or_zero_exp", [](const exp_opt_int& x) -> int {
+        return x.value_or(0) * 2;
+    });
+    m.def("half_or_none_exp", [](int x) -> exp_opt_int {
+        return x ? exp_opt_int(x / 2) : exp_opt_int();
+    });
+    m.def("test_nullopt_exp", [](exp_opt_int x) {
+        return x.value_or(42);
+    }, py::arg_v("x", std::experimental::nullopt, "None"));
+    m.def("test_no_assign_exp", [](const exp_opt_no_assign &x) {
+        return x ? x->value : 42;
+    }, py::arg_v("x", std::experimental::nullopt, "None"));
+#endif
+
+#ifdef PYBIND11_HAS_VARIANT
+    static_assert(std::is_same<py::detail::variant_caster_visitor::result_type, py::handle>::value,
+                  "visitor::result_type is required by boost::variant in C++11 mode");
+
+    struct visitor {
+        using result_type = const char *;
+
+        result_type operator()(int) { return "int"; }
+        result_type operator()(std::string) { return "std::string"; }
+        result_type operator()(double) { return "double"; }
+        result_type operator()(std::nullptr_t) { return "std::nullptr_t"; }
+    };
+
+    // test_variant
+    m.def("load_variant", [](variant<int, std::string, double, std::nullptr_t> v) {
+        return py::detail::visit_helper<variant>::call(visitor(), v);
+    });
+    m.def("load_variant_2pass", [](variant<double, int> v) {
+        return py::detail::visit_helper<variant>::call(visitor(), v);
+    });
+    m.def("cast_variant", []() {
+        using V = variant<int, std::string>;
+        return py::make_tuple(V(5), V("Hello"));
+    });
+#endif
+
+    // #528: templated constructor
+    // (no python tests: the test here is that this compiles)
+    m.def("tpl_ctor_vector", [](std::vector<TplCtorClass> &) {});
+    m.def("tpl_ctor_map", [](std::unordered_map<TplCtorClass, TplCtorClass> &) {});
+    m.def("tpl_ctor_set", [](std::unordered_set<TplCtorClass> &) {});
+#if defined(PYBIND11_HAS_OPTIONAL)
+    m.def("tpl_constr_optional", [](std::optional<TplCtorClass> &) {});
+#elif defined(PYBIND11_HAS_EXP_OPTIONAL)
+    m.def("tpl_constr_optional", [](std::experimental::optional<TplCtorClass> &) {});
+#endif
+
+    // test_vec_of_reference_wrapper
+    // #171: Can't return STL structures containing reference wrapper
+    m.def("return_vec_of_reference_wrapper", [](std::reference_wrapper<UserType> p4) {
+        static UserType p1{1}, p2{2}, p3{3};
+        return std::vector<std::reference_wrapper<UserType>> {
+            std::ref(p1), std::ref(p2), std::ref(p3), p4
+        };
+    });
+
+    // test_stl_pass_by_pointer
+    m.def("stl_pass_by_pointer", [](std::vector<int>* v) { return *v; }, "v"_a=nullptr);
+}
diff --git a/ext/pybind11/tests/test_stl.py b/ext/pybind11/tests/test_stl.py
new file mode 100644
index 000000000..db8515e7a
--- /dev/null
+++ b/ext/pybind11/tests/test_stl.py
@@ -0,0 +1,200 @@
+import pytest
+
+from pybind11_tests import stl as m
+from pybind11_tests import UserType
+
+
+def test_vector(doc):
+    """std::vector <-> list"""
+    l = m.cast_vector()
+    assert l == [1]
+    l.append(2)
+    assert m.load_vector(l)
+    assert m.load_vector(tuple(l))
+
+    assert m.cast_bool_vector() == [True, False]
+    assert m.load_bool_vector([True, False])
+
+    assert doc(m.cast_vector) == "cast_vector() -> List[int]"
+    assert doc(m.load_vector) == "load_vector(arg0: List[int]) -> bool"
+
+    # Test regression caused by 936: pointers to stl containers weren't castable
+    assert m.cast_ptr_vector() == ["lvalue", "lvalue"]
+
+
+def test_array(doc):
+    """std::array <-> list"""
+    l = m.cast_array()
+    assert l == [1, 2]
+    assert m.load_array(l)
+
+    assert doc(m.cast_array) == "cast_array() -> List[int[2]]"
+    assert doc(m.load_array) == "load_array(arg0: List[int[2]]) -> bool"
+
+
+def test_valarray(doc):
+    """std::valarray <-> list"""
+    l = m.cast_valarray()
+    assert l == [1, 4, 9]
+    assert m.load_valarray(l)
+
+    assert doc(m.cast_valarray) == "cast_valarray() -> List[int]"
+    assert doc(m.load_valarray) == "load_valarray(arg0: List[int]) -> bool"
+
+
+def test_map(doc):
+    """std::map <-> dict"""
+    d = m.cast_map()
+    assert d == {"key": "value"}
+    d["key2"] = "value2"
+    assert m.load_map(d)
+
+    assert doc(m.cast_map) == "cast_map() -> Dict[str, str]"
+    assert doc(m.load_map) == "load_map(arg0: Dict[str, str]) -> bool"
+
+
+def test_set(doc):
+    """std::set <-> set"""
+    s = m.cast_set()
+    assert s == {"key1", "key2"}
+    s.add("key3")
+    assert m.load_set(s)
+
+    assert doc(m.cast_set) == "cast_set() -> Set[str]"
+    assert doc(m.load_set) == "load_set(arg0: Set[str]) -> bool"
+
+
+def test_recursive_casting():
+    """Tests that stl casters preserve lvalue/rvalue context for container values"""
+    assert m.cast_rv_vector() == ["rvalue", "rvalue"]
+    assert m.cast_lv_vector() == ["lvalue", "lvalue"]
+    assert m.cast_rv_array() == ["rvalue", "rvalue", "rvalue"]
+    assert m.cast_lv_array() == ["lvalue", "lvalue"]
+    assert m.cast_rv_map() == {"a": "rvalue"}
+    assert m.cast_lv_map() == {"a": "lvalue", "b": "lvalue"}
+    assert m.cast_rv_nested() == [[[{"b": "rvalue", "c": "rvalue"}], [{"a": "rvalue"}]]]
+    assert m.cast_lv_nested() == {
+        "a": [[["lvalue", "lvalue"]], [["lvalue", "lvalue"]]],
+        "b": [[["lvalue", "lvalue"], ["lvalue", "lvalue"]]]
+    }
+
+    # Issue #853 test case:
+    z = m.cast_unique_ptr_vector()
+    assert z[0].value == 7 and z[1].value == 42
+
+
+def test_move_out_container():
+    """Properties use the `reference_internal` policy by default. If the underlying function
+    returns an rvalue, the policy is automatically changed to `move` to avoid referencing
+    a temporary. In case the return value is a container of user-defined types, the policy
+    also needs to be applied to the elements, not just the container."""
+    c = m.MoveOutContainer()
+    moved_out_list = c.move_list
+    assert [x.value for x in moved_out_list] == [0, 1, 2]
+
+
+@pytest.mark.skipif(not hasattr(m, "has_optional"), reason='no <optional>')
+def test_optional():
+    assert m.double_or_zero(None) == 0
+    assert m.double_or_zero(42) == 84
+    pytest.raises(TypeError, m.double_or_zero, 'foo')
+
+    assert m.half_or_none(0) is None
+    assert m.half_or_none(42) == 21
+    pytest.raises(TypeError, m.half_or_none, 'foo')
+
+    assert m.test_nullopt() == 42
+    assert m.test_nullopt(None) == 42
+    assert m.test_nullopt(42) == 42
+    assert m.test_nullopt(43) == 43
+
+    assert m.test_no_assign() == 42
+    assert m.test_no_assign(None) == 42
+    assert m.test_no_assign(m.NoAssign(43)) == 43
+    pytest.raises(TypeError, m.test_no_assign, 43)
+
+    assert m.nodefer_none_optional(None)
+
+
+@pytest.mark.skipif(not hasattr(m, "has_exp_optional"), reason='no <experimental/optional>')
+def test_exp_optional():
+    assert m.double_or_zero_exp(None) == 0
+    assert m.double_or_zero_exp(42) == 84
+    pytest.raises(TypeError, m.double_or_zero_exp, 'foo')
+
+    assert m.half_or_none_exp(0) is None
+    assert m.half_or_none_exp(42) == 21
+    pytest.raises(TypeError, m.half_or_none_exp, 'foo')
+
+    assert m.test_nullopt_exp() == 42
+    assert m.test_nullopt_exp(None) == 42
+    assert m.test_nullopt_exp(42) == 42
+    assert m.test_nullopt_exp(43) == 43
+
+    assert m.test_no_assign_exp() == 42
+    assert m.test_no_assign_exp(None) == 42
+    assert m.test_no_assign_exp(m.NoAssign(43)) == 43
+    pytest.raises(TypeError, m.test_no_assign_exp, 43)
+
+
+@pytest.mark.skipif(not hasattr(m, "load_variant"), reason='no <variant>')
+def test_variant(doc):
+    assert m.load_variant(1) == "int"
+    assert m.load_variant("1") == "std::string"
+    assert m.load_variant(1.0) == "double"
+    assert m.load_variant(None) == "std::nullptr_t"
+
+    assert m.load_variant_2pass(1) == "int"
+    assert m.load_variant_2pass(1.0) == "double"
+
+    assert m.cast_variant() == (5, "Hello")
+
+    assert doc(m.load_variant) == "load_variant(arg0: Union[int, str, float, None]) -> str"
+
+
+def test_vec_of_reference_wrapper():
+    """#171: Can't return reference wrappers (or STL structures containing them)"""
+    assert str(m.return_vec_of_reference_wrapper(UserType(4))) == \
+        "[UserType(1), UserType(2), UserType(3), UserType(4)]"
+
+
+def test_stl_pass_by_pointer(msg):
+    """Passing nullptr or None to an STL container pointer is not expected to work"""
+    with pytest.raises(TypeError) as excinfo:
+        m.stl_pass_by_pointer()  # default value is `nullptr`
+    assert msg(excinfo.value) == """
+        stl_pass_by_pointer(): incompatible function arguments. The following argument types are supported:
+            1. (v: List[int]=None) -> List[int]
+
+        Invoked with:
+    """  # noqa: E501 line too long
+
+    with pytest.raises(TypeError) as excinfo:
+        m.stl_pass_by_pointer(None)
+    assert msg(excinfo.value) == """
+        stl_pass_by_pointer(): incompatible function arguments. The following argument types are supported:
+            1. (v: List[int]=None) -> List[int]
+
+        Invoked with: None
+    """  # noqa: E501 line too long
+
+    assert m.stl_pass_by_pointer([1, 2, 3]) == [1, 2, 3]
+
+
+def test_missing_header_message():
+    """Trying convert `list` to a `std::vector`, or vice versa, without including
+    <pybind11/stl.h> should result in a helpful suggestion in the error message"""
+    import pybind11_cross_module_tests as cm
+
+    expected_message = ("Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
+                        "<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic\n"
+                        "conversions are optional and require extra headers to be included\n"
+                        "when compiling your pybind11 module.")
+
+    with pytest.raises(TypeError) as excinfo:
+        cm.missing_header_arg([1.0, 2.0, 3.0])
+    assert expected_message in str(excinfo.value)
+
+    with pytest.raises(TypeError) as excinfo:
+        cm.missing_header_return()
+    assert expected_message in str(excinfo.value)
diff --git a/ext/pybind11/tests/test_stl_binders.cpp b/ext/pybind11/tests/test_stl_binders.cpp
index f636c0b55..a88b589e1 100644
--- a/ext/pybind11/tests/test_stl_binders.cpp
+++ b/ext/pybind11/tests/test_stl_binders.cpp
@@ -15,11 +15,6 @@
 #include <deque>
 #include <unordered_map>
 
-#ifdef _MSC_VER
-// We get some really long type names here which causes MSVC to emit warnings
-#  pragma warning(disable: 4503) // warning C4503: decorated name length exceeded, name was truncated
-#endif
-
 class El {
 public:
     El() = delete;
@@ -59,70 +54,54 @@ template <class Map> Map *times_ten(int n) {
     return m;
 }
 
-struct VStruct {
-    bool w;
-    uint32_t x;
-    double y;
-    bool z;
-};
-
-struct VUndeclStruct { //dtype not declared for this version
-    bool w;
-    uint32_t x;
-    double y;
-    bool z;
-};
+TEST_SUBMODULE(stl_binders, m) {
+    // test_vector_int
+    py::bind_vector<std::vector<unsigned int>>(m, "VectorInt", py::buffer_protocol());
 
-test_initializer stl_binder_vector([](py::module &m) {
+    // test_vector_custom
     py::class_<El>(m, "El")
         .def(py::init<int>());
-
-    py::bind_vector<std::vector<unsigned char>>(m, "VectorUChar", py::buffer_protocol());
-    py::bind_vector<std::vector<unsigned int>>(m, "VectorInt", py::buffer_protocol());
-    py::bind_vector<std::vector<bool>>(m, "VectorBool");
-
     py::bind_vector<std::vector<El>>(m, "VectorEl");
-
     py::bind_vector<std::vector<std::vector<El>>>(m, "VectorVectorEl");
 
-    m.def("create_undeclstruct", [m] () mutable {
-        py::bind_vector<std::vector<VUndeclStruct>>(m, "VectorUndeclStruct", py::buffer_protocol());
-    });
-
-    try {
-        py::module::import("numpy");
-    } catch (...) {
-        return;
-    }
-    PYBIND11_NUMPY_DTYPE(VStruct, w, x, y, z);
-    py::class_<VStruct>(m, "VStruct").def_readwrite("x", &VStruct::x);
-    py::bind_vector<std::vector<VStruct>>(m, "VectorStruct", py::buffer_protocol());
-    m.def("get_vectorstruct", [] {return std::vector<VStruct> {{0, 5, 3.0, 1}, {1, 30, -1e4, 0}};});
-});
-
-test_initializer stl_binder_map([](py::module &m) {
+    // test_map_string_double
     py::bind_map<std::map<std::string, double>>(m, "MapStringDouble");
     py::bind_map<std::unordered_map<std::string, double>>(m, "UnorderedMapStringDouble");
 
+    // test_map_string_double_const
     py::bind_map<std::map<std::string, double const>>(m, "MapStringDoubleConst");
     py::bind_map<std::unordered_map<std::string, double const>>(m, "UnorderedMapStringDoubleConst");
 
-});
-
-test_initializer stl_binder_noncopyable([](py::module &m) {
     py::class_<E_nc>(m, "ENC")
         .def(py::init<int>())
         .def_readwrite("value", &E_nc::value);
 
+    // test_noncopyable_containers
     py::bind_vector<std::vector<E_nc>>(m, "VectorENC");
     m.def("get_vnc", &one_to_n<std::vector<E_nc>>, py::return_value_policy::reference);
-
     py::bind_vector<std::deque<E_nc>>(m, "DequeENC");
     m.def("get_dnc", &one_to_n<std::deque<E_nc>>, py::return_value_policy::reference);
-
     py::bind_map<std::map<int, E_nc>>(m, "MapENC");
     m.def("get_mnc", &times_ten<std::map<int, E_nc>>, py::return_value_policy::reference);
-
     py::bind_map<std::unordered_map<int, E_nc>>(m, "UmapENC");
     m.def("get_umnc", &times_ten<std::unordered_map<int, E_nc>>, py::return_value_policy::reference);
-});
+
+    // test_vector_buffer
+    py::bind_vector<std::vector<unsigned char>>(m, "VectorUChar", py::buffer_protocol());
+    // no dtype declared for this version:
+    struct VUndeclStruct { bool w; uint32_t x; double y; bool z; };
+    m.def("create_undeclstruct", [m] () mutable {
+        py::bind_vector<std::vector<VUndeclStruct>>(m, "VectorUndeclStruct", py::buffer_protocol());
+    });
+
+    // The rest depends on numpy:
+    try { py::module::import("numpy"); }
+    catch (...) { return; }
+
+    // test_vector_buffer_numpy
+    struct VStruct { bool w; uint32_t x; double y; bool z; };
+    PYBIND11_NUMPY_DTYPE(VStruct, w, x, y, z);
+    py::class_<VStruct>(m, "VStruct").def_readwrite("x", &VStruct::x);
+    py::bind_vector<std::vector<VStruct>>(m, "VectorStruct", py::buffer_protocol());
+    m.def("get_vectorstruct", [] {return std::vector<VStruct> {{0, 5, 3.0, 1}, {1, 30, -1e4, 0}};});
+}
diff --git a/ext/pybind11/tests/test_stl_binders.py b/ext/pybind11/tests/test_stl_binders.py
index 0edf9e26e..bf1aa674c 100644
--- a/ext/pybind11/tests/test_stl_binders.py
+++ b/ext/pybind11/tests/test_stl_binders.py
@@ -1,107 +1,94 @@
 import pytest
 import sys
+from pybind11_tests import stl_binders as m
 
 with pytest.suppress(ImportError):
     import numpy as np
 
 
 def test_vector_int():
-    from pybind11_tests import VectorInt
-
-    v_int = VectorInt([0, 0])
+    v_int = m.VectorInt([0, 0])
     assert len(v_int) == 2
     assert bool(v_int) is True
 
-    v_int2 = VectorInt([0, 0])
+    v_int2 = m.VectorInt([0, 0])
     assert v_int == v_int2
     v_int2[1] = 1
     assert v_int != v_int2
 
     v_int2.append(2)
-    v_int2.append(3)
     v_int2.insert(0, 1)
     v_int2.insert(0, 2)
     v_int2.insert(0, 3)
+    v_int2.insert(6, 3)
     assert str(v_int2) == "VectorInt[3, 2, 1, 0, 1, 2, 3]"
+    with pytest.raises(IndexError):
+        v_int2.insert(8, 4)
 
     v_int.append(99)
     v_int2[2:-2] = v_int
-    assert v_int2 == VectorInt([3, 2, 0, 0, 99, 2, 3])
+    assert v_int2 == m.VectorInt([3, 2, 0, 0, 99, 2, 3])
     del v_int2[1:3]
-    assert v_int2 == VectorInt([3, 0, 99, 2, 3])
+    assert v_int2 == m.VectorInt([3, 0, 99, 2, 3])
     del v_int2[0]
-    assert v_int2 == VectorInt([0, 99, 2, 3])
+    assert v_int2 == m.VectorInt([0, 99, 2, 3])
 
 
+# related to the PyPy's buffer protocol.
 @pytest.unsupported_on_pypy
 def test_vector_buffer():
-    from pybind11_tests import VectorUChar, create_undeclstruct
     b = bytearray([1, 2, 3, 4])
-    v = VectorUChar(b)
+    v = m.VectorUChar(b)
     assert v[1] == 2
     v[2] = 5
-    m = memoryview(v)  # We expose the buffer interface
+    mv = memoryview(v)  # We expose the buffer interface
     if sys.version_info.major > 2:
-        assert m[2] == 5
-        m[2] = 6
+        assert mv[2] == 5
+        mv[2] = 6
     else:
-        assert m[2] == '\x05'
-        m[2] = '\x06'
+        assert mv[2] == '\x05'
+        mv[2] = '\x06'
     assert v[2] == 6
 
-    with pytest.raises(RuntimeError):
-        create_undeclstruct()  # Undeclared struct contents, no buffer interface
+    with pytest.raises(RuntimeError) as excinfo:
+        m.create_undeclstruct()  # Undeclared struct contents, no buffer interface
+    assert "NumPy type info missing for " in str(excinfo.value)
 
 
+@pytest.unsupported_on_pypy
 @pytest.requires_numpy
 def test_vector_buffer_numpy():
-    from pybind11_tests import VectorInt, VectorStruct, get_vectorstruct
-
     a = np.array([1, 2, 3, 4], dtype=np.int32)
     with pytest.raises(TypeError):
-        VectorInt(a)
+        m.VectorInt(a)
 
     a = np.array([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]], dtype=np.uintc)
-    v = VectorInt(a[0, :])
+    v = m.VectorInt(a[0, :])
     assert len(v) == 4
     assert v[2] == 3
-    m = np.asarray(v)
-    m[2] = 5
+    ma = np.asarray(v)
+    ma[2] = 5
     assert v[2] == 5
 
-    v = VectorInt(a[:, 1])
+    v = m.VectorInt(a[:, 1])
     assert len(v) == 3
     assert v[2] == 10
 
-    v = get_vectorstruct()
+    v = m.get_vectorstruct()
     assert v[0].x == 5
-    m = np.asarray(v)
-    m[1]['x'] = 99
+    ma = np.asarray(v)
+    ma[1]['x'] = 99
     assert v[1].x == 99
 
-    v = VectorStruct(np.zeros(3, dtype=np.dtype([('w', 'bool'), ('x', 'I'),
-                                                 ('y', 'float64'), ('z', 'bool')], align=True)))
+    v = m.VectorStruct(np.zeros(3, dtype=np.dtype([('w', 'bool'), ('x', 'I'),
+                                                   ('y', 'float64'), ('z', 'bool')], align=True)))
     assert len(v) == 3
 
 
-def test_vector_custom():
-    from pybind11_tests import El, VectorEl, VectorVectorEl
-
-    v_a = VectorEl()
-    v_a.append(El(1))
-    v_a.append(El(2))
-    assert str(v_a) == "VectorEl[El{1}, El{2}]"
-
-    vv_a = VectorVectorEl()
-    vv_a.append(v_a)
-    vv_b = vv_a[0]
-    assert str(vv_b) == "VectorEl[El{1}, El{2}]"
-
-
 def test_vector_bool():
-    from pybind11_tests import VectorBool
+    import pybind11_cross_module_tests as cm
 
-    vv_c = VectorBool()
+    vv_c = cm.VectorBool()
     for i in range(10):
         vv_c.append(i % 2 == 0)
     for i in range(10):
@@ -109,18 +96,28 @@ def test_vector_bool():
     assert str(vv_c) == "VectorBool[1, 0, 1, 0, 1, 0, 1, 0, 1, 0]"
 
 
-def test_map_string_double():
-    from pybind11_tests import MapStringDouble, UnorderedMapStringDouble
+def test_vector_custom():
+    v_a = m.VectorEl()
+    v_a.append(m.El(1))
+    v_a.append(m.El(2))
+    assert str(v_a) == "VectorEl[El{1}, El{2}]"
 
-    m = MapStringDouble()
-    m['a'] = 1
-    m['b'] = 2.5
+    vv_a = m.VectorVectorEl()
+    vv_a.append(v_a)
+    vv_b = vv_a[0]
+    assert str(vv_b) == "VectorEl[El{1}, El{2}]"
 
-    assert list(m) == ['a', 'b']
-    assert list(m.items()) == [('a', 1), ('b', 2.5)]
-    assert str(m) == "MapStringDouble{a: 1, b: 2.5}"
 
-    um = UnorderedMapStringDouble()
+def test_map_string_double():
+    mm = m.MapStringDouble()
+    mm['a'] = 1
+    mm['b'] = 2.5
+
+    assert list(mm) == ['a', 'b']
+    assert list(mm.items()) == [('a', 1), ('b', 2.5)]
+    assert str(mm) == "MapStringDouble{a: 1, b: 2.5}"
+
+    um = m.UnorderedMapStringDouble()
     um['ua'] = 1.1
     um['ub'] = 2.6
 
@@ -130,35 +127,29 @@ def test_map_string_double():
 
 
 def test_map_string_double_const():
-    from pybind11_tests import MapStringDoubleConst, UnorderedMapStringDoubleConst
-
-    mc = MapStringDoubleConst()
+    mc = m.MapStringDoubleConst()
     mc['a'] = 10
     mc['b'] = 20.5
     assert str(mc) == "MapStringDoubleConst{a: 10, b: 20.5}"
 
-    umc = UnorderedMapStringDoubleConst()
+    umc = m.UnorderedMapStringDoubleConst()
     umc['a'] = 11
     umc['b'] = 21.5
 
     str(umc)
 
 
-def test_noncopyable_vector():
-    from pybind11_tests import get_vnc
-
-    vnc = get_vnc(5)
+def test_noncopyable_containers():
+    # std::vector
+    vnc = m.get_vnc(5)
     for i in range(0, 5):
         assert vnc[i].value == i + 1
 
     for i, j in enumerate(vnc, start=1):
         assert j.value == i
 
-
-def test_noncopyable_deque():
-    from pybind11_tests import get_dnc
-
-    dnc = get_dnc(5)
+    # std::deque
+    dnc = m.get_dnc(5)
     for i in range(0, 5):
         assert dnc[i].value == i + 1
 
@@ -167,11 +158,8 @@ def test_noncopyable_deque():
         assert(j.value == i)
         i += 1
 
-
-def test_noncopyable_map():
-    from pybind11_tests import get_mnc
-
-    mnc = get_mnc(5)
+    # std::map
+    mnc = m.get_mnc(5)
     for i in range(1, 6):
         assert mnc[i].value == 10 * i
 
@@ -182,11 +170,8 @@ def test_noncopyable_map():
 
     assert vsum == 150
 
-
-def test_noncopyable_unordered_map():
-    from pybind11_tests import get_umnc
-
-    mnc = get_umnc(5)
+    # std::unordered_map
+    mnc = m.get_umnc(5)
     for i in range(1, 6):
         assert mnc[i].value == 10 * i
 
diff --git a/ext/pybind11/tests/test_virtual_functions.cpp b/ext/pybind11/tests/test_virtual_functions.cpp
index 0f8ed2afb..953b390b8 100644
--- a/ext/pybind11/tests/test_virtual_functions.cpp
+++ b/ext/pybind11/tests/test_virtual_functions.cpp
@@ -145,16 +145,150 @@ class NCVirtTrampoline : public NCVirt {
     }
 };
 
-int runExampleVirt(ExampleVirt *ex, int value) {
-    return ex->run(value);
-}
+struct Base {
+    /* for some reason MSVC2015 can't compile this if the function is pure virtual */
+    virtual std::string dispatch() const { return {}; };
+    virtual ~Base() = default;
+};
 
-bool runExampleVirtBool(ExampleVirt* ex) {
-    return ex->run_bool();
-}
+struct DispatchIssue : Base {
+    virtual std::string dispatch() const {
+        PYBIND11_OVERLOAD_PURE(std::string, Base, dispatch, /* no arguments */);
+    }
+};
+
+// Forward declaration (so that we can put the main tests here; the inherited virtual approaches are
+// rather long).
+void initialize_inherited_virtuals(py::module &m);
+
+TEST_SUBMODULE(virtual_functions, m) {
+    // test_override
+    py::class_<ExampleVirt, PyExampleVirt>(m, "ExampleVirt")
+        .def(py::init<int>())
+        /* Reference original class in function definitions */
+        .def("run", &ExampleVirt::run)
+        .def("run_bool", &ExampleVirt::run_bool)
+        .def("pure_virtual", &ExampleVirt::pure_virtual);
+
+    py::class_<NonCopyable>(m, "NonCopyable")
+        .def(py::init<int, int>());
+
+    py::class_<Movable>(m, "Movable")
+        .def(py::init<int, int>());
+
+    // test_move_support
+#if !defined(__INTEL_COMPILER)
+    py::class_<NCVirt, NCVirtTrampoline>(m, "NCVirt")
+        .def(py::init<>())
+        .def("get_noncopyable", &NCVirt::get_noncopyable)
+        .def("get_movable", &NCVirt::get_movable)
+        .def("print_nc", &NCVirt::print_nc)
+        .def("print_movable", &NCVirt::print_movable);
+#endif
+
+    m.def("runExampleVirt", [](ExampleVirt *ex, int value) { return ex->run(value); });
+    m.def("runExampleVirtBool", [](ExampleVirt* ex) { return ex->run_bool(); });
+    m.def("runExampleVirtVirtual", [](ExampleVirt *ex) { ex->pure_virtual(); });
+
+    m.def("cstats_debug", &ConstructorStats::get<ExampleVirt>);
+    initialize_inherited_virtuals(m);
 
-void runExampleVirtVirtual(ExampleVirt *ex) {
-    ex->pure_virtual();
+    // test_alias_delay_initialization1
+    // don't invoke Python dispatch classes by default when instantiating C++ classes
+    // that were not extended on the Python side
+    struct A {
+        virtual ~A() {}
+        virtual void f() { py::print("A.f()"); }
+    };
+
+    struct PyA : A {
+        PyA() { py::print("PyA.PyA()"); }
+        ~PyA() { py::print("PyA.~PyA()"); }
+
+        void f() override {
+            py::print("PyA.f()");
+            PYBIND11_OVERLOAD(void, A, f);
+        }
+    };
+
+    py::class_<A, PyA>(m, "A")
+        .def(py::init<>())
+        .def("f", &A::f);
+
+    m.def("call_f", [](A *a) { a->f(); });
+
+    // test_alias_delay_initialization2
+    // ... unless we explicitly request it, as in this example:
+    struct A2 {
+        virtual ~A2() {}
+        virtual void f() { py::print("A2.f()"); }
+    };
+
+    struct PyA2 : A2 {
+        PyA2() { py::print("PyA2.PyA2()"); }
+        ~PyA2() { py::print("PyA2.~PyA2()"); }
+        void f() override {
+            py::print("PyA2.f()");
+            PYBIND11_OVERLOAD(void, A2, f);
+        }
+    };
+
+    py::class_<A2, PyA2>(m, "A2")
+        .def(py::init_alias<>())
+        .def(py::init([](int) { return new PyA2(); }))
+        .def("f", &A2::f);
+
+    m.def("call_f", [](A2 *a2) { a2->f(); });
+
+    // test_dispatch_issue
+    // #159: virtual function dispatch has problems with similar-named functions
+    py::class_<Base, DispatchIssue>(m, "DispatchIssue")
+        .def(py::init<>())
+        .def("dispatch", &Base::dispatch);
+
+    m.def("dispatch_issue_go", [](const Base * b) { return b->dispatch(); });
+
+    // test_override_ref
+    // #392/397: overridding reference-returning functions
+    class OverrideTest {
+    public:
+        struct A { std::string value = "hi"; };
+        std::string v;
+        A a;
+        explicit OverrideTest(const std::string &v) : v{v} {}
+        virtual std::string str_value() { return v; }
+        virtual std::string &str_ref() { return v; }
+        virtual A A_value() { return a; }
+        virtual A &A_ref() { return a; }
+        virtual ~OverrideTest() = default;
+    };
+
+    class PyOverrideTest : public OverrideTest {
+    public:
+        using OverrideTest::OverrideTest;
+        std::string str_value() override { PYBIND11_OVERLOAD(std::string, OverrideTest, str_value); }
+        // Not allowed (uncommenting should hit a static_assert failure): we can't get a reference
+        // to a python numeric value, since we only copy values in the numeric type caster:
+//      std::string &str_ref() override { PYBIND11_OVERLOAD(std::string &, OverrideTest, str_ref); }
+        // But we can work around it like this:
+    private:
+        std::string _tmp;
+        std::string str_ref_helper() { PYBIND11_OVERLOAD(std::string, OverrideTest, str_ref); }
+    public:
+        std::string &str_ref() override { return _tmp = str_ref_helper(); }
+
+        A A_value() override { PYBIND11_OVERLOAD(A, OverrideTest, A_value); }
+        A &A_ref() override { PYBIND11_OVERLOAD(A &, OverrideTest, A_ref); }
+    };
+
+    py::class_<OverrideTest::A>(m, "OverrideTest_A")
+        .def_readwrite("value", &OverrideTest::A::value);
+    py::class_<OverrideTest, PyOverrideTest>(m, "OverrideTest")
+        .def(py::init<const std::string &>())
+        .def("str_value", &OverrideTest::str_value)
+//      .def("str_ref", &OverrideTest::str_ref)
+        .def("A_value", &OverrideTest::A_value)
+        .def("A_ref", &OverrideTest::A_ref);
 }
 
 
@@ -179,6 +313,7 @@ public: \
         return say_something(1) + " " + std::to_string(unlucky_number()); \
     }
 A_METHODS
+    virtual ~A_Repeat() = default;
 };
 class B_Repeat : public A_Repeat {
 #define B_METHODS \
@@ -203,7 +338,7 @@ D_METHODS
 };
 
 // Base classes for templated inheritance trampolines.  Identical to the repeat-everything version:
-class A_Tpl { A_METHODS };
+class A_Tpl { A_METHODS; virtual ~A_Tpl() = default; };
 class B_Tpl : public A_Tpl { B_METHODS };
 class C_Tpl : public B_Tpl { C_METHODS };
 class D_Tpl : public C_Tpl { D_METHODS };
@@ -281,6 +416,8 @@ public:
 
 
 void initialize_inherited_virtuals(py::module &m) {
+    // test_inherited_virtuals
+
     // Method 1: repeat
     py::class_<A_Repeat, PyA_Repeat>(m, "A_Repeat")
         .def(py::init<>())
@@ -295,6 +432,7 @@ void initialize_inherited_virtuals(py::module &m) {
     py::class_<D_Repeat, C_Repeat, PyD_Repeat>(m, "D_Repeat")
         .def(py::init<>());
 
+    // test_
     // Method 2: Templated trampolines
     py::class_<A_Tpl, PyA_Tpl<>>(m, "A_Tpl")
         .def(py::init<>())
@@ -310,38 +448,3 @@ void initialize_inherited_virtuals(py::module &m) {
         .def(py::init<>());
 
 };
-
-
-test_initializer virtual_functions([](py::module &m) {
-    /* Important: indicate the trampoline class PyExampleVirt using the third
-       argument to py::class_. The second argument with the unique pointer
-       is simply the default holder type used by pybind11. */
-    py::class_<ExampleVirt, PyExampleVirt>(m, "ExampleVirt")
-        .def(py::init<int>())
-        /* Reference original class in function definitions */
-        .def("run", &ExampleVirt::run)
-        .def("run_bool", &ExampleVirt::run_bool)
-        .def("pure_virtual", &ExampleVirt::pure_virtual);
-
-    py::class_<NonCopyable>(m, "NonCopyable")
-        .def(py::init<int, int>());
-
-    py::class_<Movable>(m, "Movable")
-        .def(py::init<int, int>());
-
-#if !defined(__INTEL_COMPILER)
-    py::class_<NCVirt, NCVirtTrampoline>(m, "NCVirt")
-        .def(py::init<>())
-        .def("get_noncopyable", &NCVirt::get_noncopyable)
-        .def("get_movable", &NCVirt::get_movable)
-        .def("print_nc", &NCVirt::print_nc)
-        .def("print_movable", &NCVirt::print_movable);
-#endif
-
-    m.def("runExampleVirt", &runExampleVirt);
-    m.def("runExampleVirtBool", &runExampleVirtBool);
-    m.def("runExampleVirtVirtual", &runExampleVirtVirtual);
-
-    m.def("cstats_debug", &ConstructorStats::get<ExampleVirt>);
-    initialize_inherited_virtuals(m);
-});
diff --git a/ext/pybind11/tests/test_virtual_functions.py b/ext/pybind11/tests/test_virtual_functions.py
index b11c699df..b91ebfa3e 100644
--- a/ext/pybind11/tests/test_virtual_functions.py
+++ b/ext/pybind11/tests/test_virtual_functions.py
@@ -1,13 +1,11 @@
 import pytest
-import pybind11_tests
+
+from pybind11_tests import virtual_functions as m
 from pybind11_tests import ConstructorStats
 
 
 def test_override(capture, msg):
-    from pybind11_tests import (ExampleVirt, runExampleVirt, runExampleVirtVirtual,
-                                runExampleVirtBool)
-
-    class ExtendedExampleVirt(ExampleVirt):
+    class ExtendedExampleVirt(m.ExampleVirt):
         def __init__(self, state):
             super(ExtendedExampleVirt, self).__init__(state + 1)
             self.data = "Hello world"
@@ -33,40 +31,40 @@ def test_override(capture, msg):
         def get_string2(self):
             return "override2"
 
-    ex12 = ExampleVirt(10)
+    ex12 = m.ExampleVirt(10)
     with capture:
-        assert runExampleVirt(ex12, 20) == 30
+        assert m.runExampleVirt(ex12, 20) == 30
     assert capture == """
         Original implementation of ExampleVirt::run(state=10, value=20, str1=default1, str2=default2)
     """  # noqa: E501 line too long
 
     with pytest.raises(RuntimeError) as excinfo:
-        runExampleVirtVirtual(ex12)
+        m.runExampleVirtVirtual(ex12)
     assert msg(excinfo.value) == 'Tried to call pure virtual function "ExampleVirt::pure_virtual"'
 
     ex12p = ExtendedExampleVirt(10)
     with capture:
-        assert runExampleVirt(ex12p, 20) == 32
+        assert m.runExampleVirt(ex12p, 20) == 32
     assert capture == """
         ExtendedExampleVirt::run(20), calling parent..
         Original implementation of ExampleVirt::run(state=11, value=21, str1=override1, str2=default2)
     """  # noqa: E501 line too long
     with capture:
-        assert runExampleVirtBool(ex12p) is False
+        assert m.runExampleVirtBool(ex12p) is False
     assert capture == "ExtendedExampleVirt::run_bool()"
     with capture:
-        runExampleVirtVirtual(ex12p)
+        m.runExampleVirtVirtual(ex12p)
     assert capture == "ExtendedExampleVirt::pure_virtual(): Hello world"
 
     ex12p2 = ExtendedExampleVirt2(15)
     with capture:
-        assert runExampleVirt(ex12p2, 50) == 68
+        assert m.runExampleVirt(ex12p2, 50) == 68
     assert capture == """
         ExtendedExampleVirt::run(50), calling parent..
         Original implementation of ExampleVirt::run(state=17, value=51, str1=override1, str2=override2)
     """  # noqa: E501 line too long
 
-    cstats = ConstructorStats.get(ExampleVirt)
+    cstats = ConstructorStats.get(m.ExampleVirt)
     assert cstats.alive() == 3
     del ex12, ex12p, ex12p2
     assert cstats.alive() == 0
@@ -75,14 +73,181 @@ def test_override(capture, msg):
     assert cstats.move_constructions >= 0
 
 
-def test_inheriting_repeat():
-    from pybind11_tests import A_Repeat, B_Repeat, C_Repeat, D_Repeat, A_Tpl, B_Tpl, C_Tpl, D_Tpl
+def test_alias_delay_initialization1(capture):
+    """`A` only initializes its trampoline class when we inherit from it
+
+    If we just create and use an A instance directly, the trampoline initialization is
+    bypassed and we only initialize an A() instead (for performance reasons).
+    """
+    class B(m.A):
+        def __init__(self):
+            super(B, self).__init__()
+
+        def f(self):
+            print("In python f()")
+
+    # C++ version
+    with capture:
+        a = m.A()
+        m.call_f(a)
+        del a
+        pytest.gc_collect()
+    assert capture == "A.f()"
+
+    # Python version
+    with capture:
+        b = B()
+        m.call_f(b)
+        del b
+        pytest.gc_collect()
+    assert capture == """
+        PyA.PyA()
+        PyA.f()
+        In python f()
+        PyA.~PyA()
+    """
+
+
+def test_alias_delay_initialization2(capture):
+    """`A2`, unlike the above, is configured to always initialize the alias
+
+    While the extra initialization and extra class layer has small virtual dispatch
+    performance penalty, it also allows us to do more things with the trampoline
+    class such as defining local variables and performing construction/destruction.
+    """
+    class B2(m.A2):
+        def __init__(self):
+            super(B2, self).__init__()
+
+        def f(self):
+            print("In python B2.f()")
+
+    # No python subclass version
+    with capture:
+        a2 = m.A2()
+        m.call_f(a2)
+        del a2
+        pytest.gc_collect()
+        a3 = m.A2(1)
+        m.call_f(a3)
+        del a3
+        pytest.gc_collect()
+    assert capture == """
+        PyA2.PyA2()
+        PyA2.f()
+        A2.f()
+        PyA2.~PyA2()
+        PyA2.PyA2()
+        PyA2.f()
+        A2.f()
+        PyA2.~PyA2()
+    """
+
+    # Python subclass version
+    with capture:
+        b2 = B2()
+        m.call_f(b2)
+        del b2
+        pytest.gc_collect()
+    assert capture == """
+        PyA2.PyA2()
+        PyA2.f()
+        In python B2.f()
+        PyA2.~PyA2()
+    """
+
+
+# PyPy: Reference count > 1 causes call with noncopyable instance
+# to fail in ncv1.print_nc()
+@pytest.unsupported_on_pypy
+@pytest.mark.skipif(not hasattr(m, "NCVirt"), reason="NCVirt test broken on ICPC")
+def test_move_support():
+    class NCVirtExt(m.NCVirt):
+        def get_noncopyable(self, a, b):
+            # Constructs and returns a new instance:
+            nc = m.NonCopyable(a * a, b * b)
+            return nc
+
+        def get_movable(self, a, b):
+            # Return a referenced copy
+            self.movable = m.Movable(a, b)
+            return self.movable
+
+    class NCVirtExt2(m.NCVirt):
+        def get_noncopyable(self, a, b):
+            # Keep a reference: this is going to throw an exception
+            self.nc = m.NonCopyable(a, b)
+            return self.nc
+
+        def get_movable(self, a, b):
+            # Return a new instance without storing it
+            return m.Movable(a, b)
+
+    ncv1 = NCVirtExt()
+    assert ncv1.print_nc(2, 3) == "36"
+    assert ncv1.print_movable(4, 5) == "9"
+    ncv2 = NCVirtExt2()
+    assert ncv2.print_movable(7, 7) == "14"
+    # Don't check the exception message here because it differs under debug/non-debug mode
+    with pytest.raises(RuntimeError):
+        ncv2.print_nc(9, 9)
 
-    class AR(A_Repeat):
+    nc_stats = ConstructorStats.get(m.NonCopyable)
+    mv_stats = ConstructorStats.get(m.Movable)
+    assert nc_stats.alive() == 1
+    assert mv_stats.alive() == 1
+    del ncv1, ncv2
+    assert nc_stats.alive() == 0
+    assert mv_stats.alive() == 0
+    assert nc_stats.values() == ['4', '9', '9', '9']
+    assert mv_stats.values() == ['4', '5', '7', '7']
+    assert nc_stats.copy_constructions == 0
+    assert mv_stats.copy_constructions == 1
+    assert nc_stats.move_constructions >= 0
+    assert mv_stats.move_constructions >= 0
+
+
+def test_dispatch_issue(msg):
+    """#159: virtual function dispatch has problems with similar-named functions"""
+    class PyClass1(m.DispatchIssue):
+        def dispatch(self):
+            return "Yay.."
+
+    class PyClass2(m.DispatchIssue):
+        def dispatch(self):
+            with pytest.raises(RuntimeError) as excinfo:
+                super(PyClass2, self).dispatch()
+            assert msg(excinfo.value) == 'Tried to call pure virtual function "Base::dispatch"'
+
+            p = PyClass1()
+            return m.dispatch_issue_go(p)
+
+    b = PyClass2()
+    assert m.dispatch_issue_go(b) == "Yay.."
+
+
+def test_override_ref():
+    """#392/397: overridding reference-returning functions"""
+    o = m.OverrideTest("asdf")
+
+    # Not allowed (see associated .cpp comment)
+    # i = o.str_ref()
+    # assert o.str_ref() == "asdf"
+    assert o.str_value() == "asdf"
+
+    assert o.A_value().value == "hi"
+    a = o.A_ref()
+    assert a.value == "hi"
+    a.value = "bye"
+    assert a.value == "bye"
+
+
+def test_inherited_virtuals():
+    class AR(m.A_Repeat):
         def unlucky_number(self):
             return 99
 
-    class AT(A_Tpl):
+    class AT(m.A_Tpl):
         def unlucky_number(self):
             return 999
 
@@ -96,21 +261,21 @@ def test_inheriting_repeat():
     assert obj.unlucky_number() == 999
     assert obj.say_everything() == "hi 999"
 
-    for obj in [B_Repeat(), B_Tpl()]:
+    for obj in [m.B_Repeat(), m.B_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 13
         assert obj.lucky_number() == 7.0
         assert obj.say_everything() == "B says hi 1 times 13"
 
-    for obj in [C_Repeat(), C_Tpl()]:
+    for obj in [m.C_Repeat(), m.C_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 4444
         assert obj.lucky_number() == 888.0
         assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class CR(C_Repeat):
+    class CR(m.C_Repeat):
         def lucky_number(self):
-            return C_Repeat.lucky_number(self) + 1.25
+            return m.C_Repeat.lucky_number(self) + 1.25
 
     obj = CR()
     assert obj.say_something(3) == "B says hi 3 times"
@@ -118,7 +283,7 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 889.25
     assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class CT(C_Tpl):
+    class CT(m.C_Tpl):
         pass
 
     obj = CT()
@@ -147,14 +312,14 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 888000.0
     assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class DR(D_Repeat):
+    class DR(m.D_Repeat):
         def unlucky_number(self):
             return 123
 
         def lucky_number(self):
             return 42.0
 
-    for obj in [D_Repeat(), D_Tpl()]:
+    for obj in [m.D_Repeat(), m.D_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 4444
         assert obj.lucky_number() == 888.0
@@ -166,7 +331,7 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 42.0
     assert obj.say_everything() == "B says hi 1 times 123"
 
-    class DT(D_Tpl):
+    class DT(m.D_Tpl):
         def say_something(self, times):
             return "DT says:" + (' quack' * times)
 
@@ -189,7 +354,7 @@ def test_inheriting_repeat():
         def unlucky_number(self):
             return -3
 
-    class BT(B_Tpl):
+    class BT(m.B_Tpl):
         def say_something(self, times):
             return "BT" * times
 
@@ -204,56 +369,3 @@ def test_inheriting_repeat():
     assert obj.unlucky_number() == -7
     assert obj.lucky_number() == -1.375
     assert obj.say_everything() == "BT -7"
-
-
-# PyPy: Reference count > 1 causes call with noncopyable instance
-# to fail in ncv1.print_nc()
-@pytest.unsupported_on_pypy
-@pytest.mark.skipif(not hasattr(pybind11_tests, 'NCVirt'),
-                    reason="NCVirt test broken on ICPC")
-def test_move_support():
-    from pybind11_tests import NCVirt, NonCopyable, Movable
-
-    class NCVirtExt(NCVirt):
-        def get_noncopyable(self, a, b):
-            # Constructs and returns a new instance:
-            nc = NonCopyable(a * a, b * b)
-            return nc
-
-        def get_movable(self, a, b):
-            # Return a referenced copy
-            self.movable = Movable(a, b)
-            return self.movable
-
-    class NCVirtExt2(NCVirt):
-        def get_noncopyable(self, a, b):
-            # Keep a reference: this is going to throw an exception
-            self.nc = NonCopyable(a, b)
-            return self.nc
-
-        def get_movable(self, a, b):
-            # Return a new instance without storing it
-            return Movable(a, b)
-
-    ncv1 = NCVirtExt()
-    assert ncv1.print_nc(2, 3) == "36"
-    assert ncv1.print_movable(4, 5) == "9"
-    ncv2 = NCVirtExt2()
-    assert ncv2.print_movable(7, 7) == "14"
-    # Don't check the exception message here because it differs under debug/non-debug mode
-    with pytest.raises(RuntimeError):
-        ncv2.print_nc(9, 9)
-
-    nc_stats = ConstructorStats.get(NonCopyable)
-    mv_stats = ConstructorStats.get(Movable)
-    assert nc_stats.alive() == 1
-    assert mv_stats.alive() == 1
-    del ncv1, ncv2
-    assert nc_stats.alive() == 0
-    assert mv_stats.alive() == 0
-    assert nc_stats.values() == ['4', '9', '9', '9']
-    assert mv_stats.values() == ['4', '5', '7', '7']
-    assert nc_stats.copy_constructions == 0
-    assert mv_stats.copy_constructions == 1
-    assert nc_stats.move_constructions >= 0
-    assert mv_stats.move_constructions >= 0