def test_installReactorBogus(self):
        """
        L{TwistOptions.installReactor} raises UsageError if an unknown reactor
        is specified.
        """
        self.patchInstallReactor()

        options = TwistOptions()
        self.assertRaises(UsageError, options.opt_reactor, "coal")

        L{TwistOptions.installReactor} raises UsageError if an unknown reactor
        is specified.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/twist/test/test_options.py