Remove git lockfile flakiness on win (bot_update)

tests/bot_update_coverage_test.py

 #!/usr/bin/env python
 # Copyright (c) 2015 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.
 
 import codecs
 import copy
 import json
 import os
 import sys
@@ skipping 157 matching lines @@
     self.call = MockedCall(self.filesystem)
     self.gclient = MockedGclientSync(self.filesystem)
     self.call.expect(('gclient', 'sync')).returns(self.gclient)
     self.old_call = getattr(bot_update, 'call')
     self.params = copy.deepcopy(DEFAULT_PARAMS)
     setattr(bot_update, 'call', self.call)
     setattr(bot_update, 'git', fake_git)
 
     self.old_os_cwd = os.getcwd
     setattr(os, 'getcwd', lambda: '/b/build/slave/foo/build')
+    self.old_os_listdir = os.listdir
+    setattr(os, 'listdir', lambda _: ['a.lock', 'b.lock', 'c.txt'])
 
     setattr(bot_update, 'open', self.filesystem.open)
     self.old_codecs_open = codecs.open
     setattr(codecs, 'open', self.filesystem.open)
 
   def tearDown(self):
     setattr(bot_update, 'call', self.old_call)
     setattr(os, 'getcwd', self.old_os_cwd)
+    setattr(os, 'listdir', self.old_os_listdir)
     delattr(bot_update, 'open')
     setattr(codecs, 'open', self.old_codecs_open)
 
   def testBasic(self):
     bot_update.ensure_checkout(**self.params)
     return self.call.records
 
   def testBasicShallow(self):
     self.params['shallow'] = True
     bot_update.ensure_checkout(**self.params)
     return self.call.records
 
+  def testRemoveGitLockfiles(self):
+    bot_update.remove_git_lockfiles('win32', 'E:/b/c/b/win/src',1)
+    self.assertTrue((('cmd.exe', '/c', 'del', '/f', '/q',
+                      'E:/b/c/b/win/src/.git/a.lock'), {}) in self.call.records)
+    self.assertTrue((('cmd.exe', '/c', 'del', '/f', '/q',
+                      'E:/b/c/b/win/src/.git/b.lock'), {}) in self.call.records)
+    self.assertFalse((('cmd.exe', '/c', 'del', '/f', '/q',
+                       'E:/b/c/b/win/src/.git/c.txt'), {}) in self.call.records)
+
+  def testRemoveGitLockfilesInBadDirectory(self):
+    setattr(os, 'listdir', self.old_os_listdir)
+    # If a directory doesn't exist, we don't want this method to raise an
+    # Exception
+    self.assertEqual(bot_update.remove_git_lockfiles(
+          'win32', 'this/dir/does/not/exist'), None)
 
 if __name__ == '__main__':
   unittest.main()