def test_installCorrectReactor(self):
        """
        L{TwistOptions.installReactor} installs the chosen reactor after the
        command line options have been parsed.
        """
        self.patchInstallReactor()

        options = TwistOptions()
        options.subCommand = "test-subcommand"
        options.parseOptions(["--reactor=fusion"])

        self.assertEqual(set(self.installedReactors), set(["fusion"]))

        L{TwistOptions.installReactor} installs the chosen reactor after the
        command line options have been parsed.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/twist/test/test_options.py