def METHOD_NAME(self):
    with session.begin():
        client_config = create_client_config(username=None, password=None)
    comment_text = u'Never gonna make you cry'
    try:
        run_client(['bkr', 'job-comment', self.job.recipesets[0].t_id,
                    '--message', comment_text], config=client_config)
        self.fail('should raise')
    except ClientError as e:
        self.assertEquals(e.status, 1)
        self.assertIn('Invalid username or password', e.stderr_output)