'``BuildScript.main`` raises ``SystemExit`` if there are missing command
line options.'

def test_usage_error_status(self):

    fake_sys_module = FakeSysModule(argv=[])
    script = BuildScript(sys_module=fake_sys_module)
    exception = self.assertRaises(SystemExit, script.main, top_level=FLOCKER_PATH)
    self.assertEqual(1, exception.code)
