Fixes RunPythonUnitTests output.

presubmit_canned_checks.py

 #!/usr/bin/env python
 # Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 
 ### Description checks
 
@@ skipping 151 matching lines @@
     message_type = output_api.PresubmitNotifyResult
   tests_suite = []
   outputs = []
   for unit_test in unit_tests:
     try:
       tests_suite.extend(_RunPythonUnitTests_LoadTests(input_api, unit_test))
     except ImportError:
       outputs.append(message_type("Failed to load %s" % unit_test,
                                   long_text=input_api.traceback.format_exc()))
 
-  results = input_api.unittest.TextTestRunner(verbosity=0).run(
+  buffer = input_api.cStringIO.StringIO()
+  results = input_api.unittest.TextTestRunner(stream=buffer, verbosity=0).run(
       input_api.unittest.TestSuite(tests_suite))
   if not results.wasSuccessful():
     outputs.append(message_type("%d unit tests failed." %
-                                (len(results.failures) + len(results.errors))))
+                                (len(results.failures) + len(results.errors)),
+                                long_text=buffer.getvalue()))
   return outputs