Fix R= line rewriter to handle TBRs well.

tests/git_cl_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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 git_cl.py."""
 
 import os
 import StringIO
 import stat
@@ skipping 674 matching lines @@
         ((['git', 'config', 'rietveld.viewvc-url'],), ''),
         (('ViewVC URL:',), ''),
         # DownloadHooks(True)
         ((commit_msg_path, os.X_OK,), True),
         ]
     git_cl.main(['config'])
 
   def test_update_reviewers(self):
     data = [
       ('foo', [], 'foo'),
+      ('foo\nR=xx', [], 'foo\nR=xx'),
+      ('foo\nTBR=xx', [], 'foo\nTBR=xx'),
       ('foo', ['a@c'], 'foo\n\nR=a@c'),
+      ('foo\nR=xx', ['a@c'], 'foo\n\nR=a@c, xx'),
+      ('foo\nTBR=xx', ['a@c'], 'foo\n\nR=a@c\nTBR=xx'),
+      ('foo\nTBR=xx\nR=yy', ['a@c'], 'foo\n\nR=a@c, yy\nTBR=xx'),
       ('foo\nBUG=', ['a@c'], 'foo\nBUG=\nR=a@c'),
-      ('foo\nR=xx\nTBR=yy\nR=bar', ['a@c'], 'foo\nTBR=a@c'),
+      ('foo\nR=xx\nTBR=yy\nR=bar', ['a@c'], 'foo\n\nR=a@c, xx, bar\nTBR=yy'),
       ('foo', ['a@c', 'b@c'], 'foo\n\nR=a@c, b@c'),
       ('foo\nBar\n\nR=\nBUG=', ['c@c'], 'foo\nBar\n\nR=c@c\nBUG='),
       ('foo\nBar\n\nR=\nBUG=\nR=', ['c@c'], 'foo\nBar\n\nR=c@c\nBUG='),
       # Same as the line before, but full of whitespaces.
       (
         'foo\nBar\n\n R = \n BUG = \n R = ', ['c@c'],
         'foo\nBar\n\nR=c@c\n BUG =',
       ),
       # Whitespaces aren't interpreted as new lines.
       ('foo BUG=allo R=joe ', ['c@c'], 'foo BUG=allo R=joe\n\nR=c@c'),
     ]
     expected = [i[2] for i in data]
     actual = []
     for orig, reviewers, _expected in data:
       obj = git_cl.ChangeDescription(orig)
       obj.update_reviewers(reviewers)
       actual.append(obj.description)
     self.assertEqual(expected, actual)
 
 
 if __name__ == '__main__':
   git_cl.logging.basicConfig(
       level=git_cl.logging.DEBUG if '-v' in sys.argv else git_cl.logging.ERROR)
   unittest.main()