Return OS status code from python test driver scripts.

testing/tools/run_corpus_tests.py

 #!/usr/bin/env python
 # Copyright 2015 The PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import optparse
 import os
 import re
 import subprocess
 import sys
@@ skipping 21 matching lines @@
       actual_path = actual_path_template % i;
       if not os.path.exists(expected_path):
         if i == 0:
           print "WARNING: no expected results files found for " + input_filename
         break
       print "Checking " + actual_path
       subprocess.check_call([pdfium_diff_path, expected_path, actual_path])
       i += 1
   except subprocess.CalledProcessError as e:
     print "FAILURE: " + input_filename + "; " + str(e)
+    return False
+  return True
 
 def main():
   parser = optparse.OptionParser()
   parser.add_option('--build-dir', default=os.path.join('out', 'Debug'),
                     help='relative path from the base source directory')
   options, args = parser.parse_args()
 
   # Expect |my_dir| to be .../pdfium/testing/tools.
   my_dir = os.path.dirname(os.path.realpath(__file__))
   testing_dir = os.path.dirname(my_dir)
@@ skipping 24 matching lines @@
     pdfium_test_path = pdfium_test_path + '.exe'
     pdfium_diff_path = pdfium_diff_path + '.exe'
   # TODO(tsepez): Mac may require special handling here.
 
   # Place generated files under the build directory, not source directory.
   working_dir = os.path.join(build_dir, 'gen', 'pdfium', 'testing', 'corpus')
   if not os.path.exists(working_dir):
     os.makedirs(working_dir)
 
   # test files are under .../pdfium/testing/corpus.
+  os_exit_code = 0
   walk_from_dir = os.path.join(testing_dir, 'corpus');
   input_file_re = re.compile('^[a-zA-Z0-9_.]+[.]pdf$')
   for source_dir, _, filename_list in os.walk(walk_from_dir):
     for input_filename in filename_list:
       if input_file_re.match(input_filename):
          input_path = os.path.join(source_dir, input_filename)
          if os.path.isfile(input_path):
-           test_one_file(input_filename, source_dir, working_dir,
-                         pdfium_test_path, pdfium_diff_path)
-  return 0
+           if not test_one_file(input_filename, source_dir, working_dir,
+                                pdfium_test_path, pdfium_diff_path):
+             os_exit_code = 1
+
+  return os_exit_code
 
 
 if __name__ == '__main__':
   sys.exit(main())