'Running it on trunk always gives green.'

def test_trunk(self):

    logs = []
    with self.assertRaises(SystemExit) as e:
        CheckNewsfragmentScript(logs.append).main([self.repo.path])
    self.assertEqual(e.exception.args, (0,))
    self.assertEqual(logs[(-1)], 'On    trunk    or    no    diffs    from    trunk;    no    need    to    look    at    this.')
