Create CachingRietveld to automatically cache results for presubmit checks.

tests/git_cl_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Unit tests for git_cl.py."""
 
 import os
 import StringIO
 import stat
@@ skipping 51 matching lines @@
     self.mock(subprocess2, 'check_call', self._mocked_call)
     self.mock(subprocess2, 'check_output', self._mocked_call)
     self.mock(subprocess2, 'communicate', self._mocked_call)
     self.mock(subprocess2, 'Popen', self._mocked_call)
     self.mock(git_cl, 'FindCodereviewSettingsFile', lambda: '')
     self.mock(git_cl, 'ask_for_data', self._mocked_call)
     self.mock(git_cl.breakpad, 'post', self._mocked_call)
     self.mock(git_cl.breakpad, 'SendStack', self._mocked_call)
     self.mock(git_cl.presubmit_support, 'DoPresubmitChecks', PresubmitMock)
     self.mock(git_cl.rietveld, 'Rietveld', RietveldMock)
+    self.mock(git_cl.rietveld, 'CachingRietveld', RietveldMock)
     self.mock(git_cl.upload, 'RealMain', self.fail)
     self.mock(git_cl.watchlists, 'Watchlists', WatchlistsMock)
     # It's important to reset settings to not have inter-tests interference.
     git_cl.settings = None
 
   def tearDown(self):
     if not self.has_failed():
       self.assertEquals([], self.calls)
     super(TestGitCl, self).tearDown()
 
@@ skipping 497 matching lines @@
         ((['git', 'config', 'rietveld.viewvc-url'],), ''),
         (('ViewVC URL:',), ''),
         # DownloadHooks(True)
         ((commit_msg_path, os.X_OK,), True),
         ]
     git_cl.main(['config'])
 
 
 if __name__ == '__main__':
   unittest.main()