Add auto_stub mocking library.

testing_support/git/unittest_helpers.py

 # Copyright 2014 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.
 
-import unittest
-
+from testing_support import auto_stub
 
 from testing_support.git.repo import GitRepo
 from testing_support.git.schema import GitRepoSchema
 
 
-class GitRepoSchemaTestBase(unittest.TestCase):
+class GitRepoSchemaTestBase(auto_stub.TestCase):
   """A TestCase with a built-in GitRepoSchema.
 
   Expects a class variable REPO_SCHEMA to be a GitRepoSchema string in the form
   described by that class.
 
   You may also set class variables in the form COMMIT_%(commit_name)s, which
   provide the content for the given commit_name commits.
 
   You probably will end up using either GitRepoReadOnlyTestBase or
   GitRepoReadWriteTestBase for real tests.
@@ skipping 49 matching lines @@
     self.repo = GitRepo(self.r_schema)
 
   def tearDown(self):
     self.repo.nuke()
     super(GitRepoReadWriteTestBase, self).tearDown()
 
   def assertSchema(self, schema_string):
     self.assertEqual(GitRepoSchema(schema_string).simple_graph(),
                      self.repo.to_schema().simple_graph())