def test_usage_error_message(self):
        """
        ``DockerBuildScript.main`` prints a usage error to ``stderr`` if there
        are missing command line options.
        """
        fake_sys_module = FakeSysModule(argv=[])
        script = DockerBuildScript(sys_module=fake_sys_module)
        try:
            script.main()
        except __HOLE__:
            pass
        self.assertEqual(
            'Wrong number of arguments.',
            fake_sys_module.stderr.getvalue().splitlines()[-1]
        )
dataset/ETHPy150Open ClusterHQ/flocker/admin/test/test_packaging.py/DockerBuildScriptTests.test_usage_error_message