Create a new depot_tools_testing_lib to move utility modules there

tests/gclient_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 gclient.py.
 
 See gclient_smoketest.py for integration tests.
 """
 
 from __future__ import with_statement
 import Queue
 import logging
 import os
 import sys
 import unittest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import gclient
 import gclient_utils
-from tests import trial_dir
+from testing_support import trial_dir
 
 
 def write(filename, content):
   """Writes the content of a file and create the directories as needed."""
   filename = os.path.abspath(filename)
   dirname = os.path.dirname(filename)
   if not os.path.isdir(dirname):
     os.makedirs(dirname)
   with open(filename, 'w') as f:
     f.write(content)
@@ skipping 218 matching lines @@
   sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
   sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout, include_zero=True)
   sys.stderr = gclient_utils.MakeFileAutoFlush(sys.stderr)
   sys.stderr = gclient_utils.MakeFileAnnotated(sys.stderr, include_zero=True)
   logging.basicConfig(
       level=[logging.ERROR, logging.WARNING, logging.INFO, logging.DEBUG][
         min(sys.argv.count('-v'), 3)],
       format='%(relativeCreated)4d %(levelname)5s %(module)13s('
               '%(lineno)d) %(message)s')
   unittest.main()