Add InputApi.is_committing to be able to return a failure or notification, depending on the check.

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."""
 
 
 def CheckChangeHasTestField(input_api, output_api):
   """Requires that the changelist have a TEST= field."""
@@ skipping 107 matching lines @@
 
 def _RunPythonUnitTests_LoadTests(input_api, module_name):
   """Meant to be stubbed out during unit testing."""
   module = __import__(module_name)
   for part in module_name.split('.')[1:]:
     module = getattr(module, part)
   return input_api.unittest.TestLoader().loadTestsFromModule(module)._tests
 
 def RunPythonUnitTests(input_api, output_api, unit_tests):
   """Imports the unit_tests modules and run them."""
+  # We don't want to hinder users from uploading incomplete patches.
+  if input_api.is_committing:
+    message_type = output_api.PresubmitError
+  else:
+    message_type = output_api.PresubmitNotifyResult
   tests_suite = []
   outputs = []
   for unit_test in unit_tests:
     try:
       tests_suite.extend(_RunPythonUnitTests_LoadTests(unit_test))
     except ImportError:
-      outputs.append(output_api.PresubmitError("Failed to load %s" % unit_test))
+      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(
       input_api.unittest.TestSuite(tests_suite))
   if not results.wasSuccessful():
-    outputs.append(output_api.PresubmitError(
+    outputs.append(message_type(
         "%d unit tests failed." % (results.failures + results.errors)))
   return outputs