tests,ext: Add a new testing library proposal

The new test library is split into two parts: The framework which resides
in ext/, and the gem5 helping components in /tests/gem5.

Change-Id: Ib4f3ae8d7eb96a7306335a3e739b7e8041aa99b9
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/4421
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

1 files changed, 193 insertions, 0 deletions

diff --git a/ext/testlib/sandbox.py b/ext/testlib/sandbox.py
new file mode 100644
index 000000000..7f8fe2d3b
--- /dev/null
+++ b/ext/testlib/sandbox.py
@@ -0,0 +1,193 @@
+# Copyright (c) 2017 Mark D. Hill and David A. Wood
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Sean Wilson
+
+import multiprocessing
+import pdb
+import os
+import sys
+import threading
+import traceback
+
+import log
+
+pdb._Pdb = pdb.Pdb
+class ForkedPdb(pdb._Pdb):
+    '''
+    A Pdb subclass that may be used from a forked multiprocessing child
+    '''
+    io_manager = None
+    def interaction(self, *args, **kwargs):
+        _stdin = sys.stdin
+        self.io_manager.restore_pipes()
+        try:
+            sys.stdin = open('/dev/stdin')
+            pdb._Pdb.interaction(self, *args, **kwargs)
+        finally:
+            sys.stdin = _stdin
+            self.io_manager.replace_pipes()
+
+
+#TODO Refactor duplicate stdout, stderr logic
+class IoManager(object):
+    def __init__(self, test, suite):
+        self.test = test
+        self.suite = suite
+        self.log = log.test_log
+        self._init_pipes()
+
+    def _init_pipes(self):
+        self.stdout_rp, self.stdout_wp = os.pipe()
+        self.stderr_rp, self.stderr_wp = os.pipe()
+
+    def close_parent_pipes(self):
+        os.close(self.stdout_wp)
+        os.close(self.stderr_wp)
+
+    def setup(self):
+        self.replace_pipes()
+        self.fixup_pdb()
+
+    def fixup_pdb(self):
+        ForkedPdb.io_manager = self
+        pdb.Pdb = ForkedPdb
+
+    def replace_pipes(self):
+        self.old_stderr = os.dup(sys.stderr.fileno())
+        self.old_stdout = os.dup(sys.stdout.fileno())
+
+        os.dup2(self.stderr_wp, sys.stderr.fileno())
+        sys.stderr = os.fdopen(self.stderr_wp, 'w', 0)
+        os.dup2(self.stdout_wp, sys.stdout.fileno())
+        sys.stdout = os.fdopen(self.stdout_wp, 'w', 0)
+
+    def restore_pipes(self):
+        self.stderr_wp = os.dup(sys.stderr.fileno())
+        self.stdout_wp = os.dup(sys.stdout.fileno())
+
+        os.dup2(self.old_stderr, sys.stderr.fileno())
+        sys.stderr = os.fdopen(self.old_stderr, 'w', 0)
+        os.dup2(self.old_stdout, sys.stdout.fileno())
+        sys.stdout = os.fdopen(self.old_stdout, 'w', 0)
+
+    def start_loggers(self):
+        self.log_ouput()
+
+    def log_ouput(self):
+        def _log_output(pipe, log_callback):
+            with os.fdopen(pipe, 'r') as pipe:
+                # Read iteractively, don't allow input to fill the pipe.
+                for line in iter(pipe.readline, ''):
+                    log_callback(line)
+
+        # Don't keep a backpointer to self in the thread.
+        log = self.log
+        test = self.test
+        suite = self.suite
+
+        self.stdout_thread = threading.Thread(
+                target=_log_output,
+                args=(self.stdout_rp,
+                      lambda buf: log.test_stdout(test, suite, buf))
+        )
+        self.stderr_thread = threading.Thread(
+                target=_log_output,
+                args=(self.stderr_rp,
+                      lambda buf: log.test_stderr(test, suite, buf))
+        )
+
+        # Daemon + Join to not lock up main thread if something breaks
+        # but provide consistent execution if nothing goes wrong.
+        self.stdout_thread.daemon = True
+        self.stderr_thread.daemon = True
+        self.stdout_thread.start()
+        self.stderr_thread.start()
+
+    def join_loggers(self):
+        self.stdout_thread.join()
+        self.stderr_thread.join()
+
+
+class SubprocessException(Exception):
+    def __init__(self, exception, trace):
+        super(SubprocessException, self).__init__(trace)
+
+class ExceptionProcess(multiprocessing.Process):
+    class Status():
+        def __init__(self, exitcode, exception_tuple):
+            self.exitcode = exitcode
+            if exception_tuple is not None:
+                self.trace = exception_tuple[1]
+                self.exception = exception_tuple[0]
+            else:
+                self.exception = None
+                self.trace = None
+
+    def __init__(self, *args, **kwargs):
+        multiprocessing.Process.__init__(self, *args, **kwargs)
+        self._pconn, self._cconn = multiprocessing.Pipe()
+        self._exception = None
+
+    def run(self):
+        try:
+            super(ExceptionProcess, self).run()
+            self._cconn.send(None)
+        except Exception as e:
+            tb = traceback.format_exc()
+            self._cconn.send((e, tb))
+            raise
+
+    @property
+    def status(self):
+        if self._pconn.poll():
+            self._exception = self._pconn.recv()
+
+        return self.Status(self.exitcode, self._exception)
+
+
+class Sandbox(object):
+    def __init__(self, test_parameters):
+
+        self.params = test_parameters
+        self.io_manager = IoManager(self.params.test, self.params.suite)
+
+        self.p = ExceptionProcess(target=self.entrypoint)
+        # Daemon + Join to not lock up main thread if something breaks
+        self.p.daemon = True
+        self.io_manager.start_loggers()
+        self.p.start()
+        self.io_manager.close_parent_pipes()
+        self.p.join()
+        self.io_manager.join_loggers()
+
+        status = self.p.status
+        if status.exitcode:
+            raise SubprocessException(status.exception, status.trace)
+
+    def entrypoint(self):
+        self.io_manager.setup()
+        self.params.test.test(self.params)