def METHOD_NAME(self, load_mock, mock_stdout):
    load_mock.side_effect = RuntimeError("fail to load")
    with self.assertRaises(SystemExit) as system_error:
        main(["-w", "200", "-e", "300", "myserver.com/myimg.jpg"])
    expect(mock_stdout.getvalue()).to_equal(
        "Error: The -k or --key argument is mandatory. "
        "For more information type thumbor-url -h\n"
    )
    expect(system_error.exception.code).to_equal(1)