Fix tests on Windows

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
 
 ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, os.path.join(ROOT_DIR, '..'))
 
 import patch
 from tests.patches_data import GIT, RAW
 
 
@@ skipping 126 matching lines @@
         'foo',
         'other/place/foo',
         'tools/clang_check/README.chromium',
     ]
     self.assertEquals(expected, patches.filenames)
 
     # Test patch #4.
     orig_name = patches.patches[4].filename
     orig_source_name = patches.patches[4].source_filename or orig_name
     patches.set_relpath(os.path.join('a', 'bb'))
-    expected = [os.path.join('a', 'bb', x) for x in expected]
+    # Expect posixpath all the time.
+    expected = [posixpath.join('a', 'bb', x) for x in expected]
     self.assertEquals(expected, patches.filenames)
     # Make sure each header is updated accordingly.
     header = []
-    new_name = os.path.join('a', 'bb', orig_name)
-    new_source_name = os.path.join('a', 'bb', orig_source_name)
+    new_name = posixpath.join('a', 'bb', orig_name)
+    new_source_name = posixpath.join('a', 'bb', orig_source_name)
     for line in RAW.PATCH.splitlines(True):
       if line.startswith('@@'):
         break
       if line[:3] == '---':
         line = line.replace(orig_source_name, new_source_name)
       if line[:3] == '+++':
         line = line.replace(orig_name, new_name)
       header.append(line)
     header = ''.join(header)
     self.assertEquals(header, patches.patches[4].diff_header)
@@ skipping 280 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()