combine base_unittest.py modules from gm and tools

gm/rebaseline_server/imagediffdb_test.py

 #!/usr/bin/python
 
 """
 Copyright 2013 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Test imagediffdb.py
 """
 
 # System-level imports
 import logging
 import shutil
 import tempfile
 import unittest
 
 # Local imports
 import imagediffdb
 
 
 IMG_URL_BASE = ('http://chromium-skia-gm.commondatastorage.googleapis.com/gm/'
                 'bitmap-64bitMD5/')
 
 
 class ImageDiffDbTest(unittest.TestCase):
 
   def setUp(self):
-    self._temp_dir = tempfile.mkdtemp()
+    self.temp_dir = tempfile.mkdtemp()
     self.maxDiff = None
 
   def tearDown(self):
-    shutil.rmtree(self._temp_dir)
+    shutil.rmtree(self.temp_dir)
 
   def shortDescription(self):
     """Tell unittest framework to not print docstrings for test cases."""
     return None
 
   def test_sanitize_locator(self):
     """Test _sanitize_locator()."""
     self.assertEqual(imagediffdb._sanitize_locator('simple'), 'simple')
     self.assertEqual(imagediffdb._sanitize_locator(1234), '1234')
     self.assertEqual(imagediffdb._sanitize_locator('one/two'),  'one_two')
@@ skipping 25 matching lines @@
         [
             'gradients_degenerate_2pt/10552995703607727960',
             IMG_URL_BASE + 'gradients_degenerate_2pt/10552995703607727960.png',
             'gradients_degenerate_2pt/11198253335583713230',
             IMG_URL_BASE + 'gradients_degenerate_2pt/11198253335583713230.png',
             '100.0000', '100.0000', [255, 0, 255],
         ],
     ]
 
     # Add all image pairs to the database
-    db = imagediffdb.ImageDiffDB(self._temp_dir)
+    db = imagediffdb.ImageDiffDB(self.temp_dir)
     for selftest in selftests:
       retval = db.add_image_pair(
           expected_image_locator=selftest[0], expected_image_url=selftest[1],
           actual_image_locator=selftest[2],   actual_image_url=selftest[3])
 
     # Fetch each image pair from the database
     for selftest in selftests:
       record = db.get_diff_record(expected_image_locator=selftest[0],
                                   actual_image_locator=selftest[2])
       self.assertEqual('%.4f' % record.get_percent_pixels_differing(),
                        selftest[4])
       self.assertEqual('%.4f' % record.get_perceptual_difference(), selftest[5])
       self.assertEqual(record.get_max_diff_per_channel(), selftest[6])
 
 
 def main():
   suite = unittest.TestLoader().loadTestsFromTestCase(ImageDiffDbTest)
   unittest.TextTestRunner(verbosity=2).run(suite)
 
 
 if __name__ == '__main__':
   main()