Create a new depot_tools_testing_lib to move utility modules there

tests/gcl_unittest.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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 gcl.py."""
 
 # pylint: disable=E1103,E1101,E1120
 
 import os
 import sys
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from super_mox import mox, SuperMoxTestBase
+from testing_support.super_mox import mox, SuperMoxTestBase
 
 import gcl
 import presubmit_support
 
 
 class GclTestsBase(SuperMoxTestBase):
   """Setups and tear downs the mocks but doesn't test anything as-is."""
   def setUp(self):
     SuperMoxTestBase.setUp(self)
     self.fake_root_dir = self.RootDir()
@@ skipping 561 matching lines @@
     self.assertEquals(change_info.description,
         'deescription\n\nCommitted: http://view/12345')
     # pylint: disable=W0212
     self.assertTrue(change_info._deleted)
     self.assertTrue(change_info._closed)
 
 
 if __name__ == '__main__':
   import unittest
   unittest.main()