Use platform specific test results as fallback in difference tests

So far, we have only two Windows tests require to use platform specific
test results due to platform idiosyncracies. However, VS2015 has fixed
those issues.
So in general, We only need to use platform based results if checking
against the regular results failed.

Review URL: https://codereview.chromium.org/1892013003

1 files changed, 18 insertions, 7 deletions

diff --git a/testing/tools/pngdiffer.py b/testing/tools/pngdiffer.py
index bef252674f..79d1b7588a 100755
--- a/testing/tools/pngdiffer.py
+++ b/testing/tools/pngdiffer.py
@@ -49,21 +49,32 @@ class PNGDiffer():
     while True:
       actual_path = actual_path_template % i
       expected_path = expected_path_template % i
+      # PDFium tests should be platform independent. Platform based results are
+      # used to capture platform dependent implementations.
       platform_expected_path = (
           platform_expected_path_template % (self.os_name, i))
-      if os.path.exists(platform_expected_path):
-        expected_path = platform_expected_path
-      elif not os.path.exists(expected_path):
+      if (not os.path.exists(expected_path) and
+          not os.path.exists(platform_expected_path)):
         if i == 0:
           print "WARNING: no expected results files for " + input_filename
         break
       print "Checking " + actual_path
       sys.stdout.flush()
-      error = common.RunCommand(
-          [self.pdfium_diff_path, expected_path, actual_path], redirect_output)
+      if os.path.exists(expected_path):
+        error = common.RunCommand(
+            [self.pdfium_diff_path, expected_path, actual_path],
+            redirect_output)
+      else:
+        error = 1;
       if error:
-        print "FAILURE: " + input_filename + "; " + str(error)
-        return True
+        # When failed, we check against platform based results.
+        if os.path.exists(platform_expected_path):
+          error = common.RunCommand(
+              [self.pdfium_diff_path, platform_expected_path, actual_path],
+              redirect_output)
+        if error:
+          print "FAILURE: " + input_filename + "; " + str(error)
+          return True
       i += 1
     return False