Remove git lockfile flakiness on win (bot_update)

tests/bot_update_coverage_test.py

Index: tests/bot_update_coverage_test.py
diff --git a/tests/bot_update_coverage_test.py b/tests/bot_update_coverage_test.py
index f055a9ba64b64c296420cf64bfa3ca39cbda4347..0948e81311396f613f7f71b39f87287381186f5a 100755
--- a/tests/bot_update_coverage_test.py
+++ b/tests/bot_update_coverage_test.py
@@ -175,6 +175,8 @@ class BotUpdateUnittests(unittest.TestCase):
 
     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
@@ -183,6 +185,7 @@ class BotUpdateUnittests(unittest.TestCase):
   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)
 
@@ -195,6 +198,21 @@ class BotUpdateUnittests(unittest.TestCase):
     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()