Create a new depot_tools_testing_lib to move utility modules there

tests/patch_test.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 patch.py."""
 
 import logging
 import os
 import posixpath
 import sys
 import unittest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+from testing_support.patches_data import GIT, RAW
+
 import patch
-from tests.patches_data import GIT, RAW
 
 
 class PatchTest(unittest.TestCase):
   def _check_patch(self,
       p,
       filename,
       diff,
       source_filename=None,
       is_binary=False,
       is_delete=False,
@@ skipping 423 matching lines @@
       self.fail()
     except patch.UnsupportedPatchFormat:
       pass
 
 
 if __name__ == '__main__':
   logging.basicConfig(level=
       [logging.WARNING, logging.INFO, logging.DEBUG][
         min(2, sys.argv.count('-v'))])
   unittest.main()