def test_reactor(self):
        """
        L{TwistOptions.installReactor} installs the chosen reactor and sets
        the reactor name.
        """
        self.patchInstallReactor()

        options = TwistOptions()
        options.opt_reactor("fusion")

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

        L{TwistOptions.installReactor} installs the chosen reactor and sets
        the reactor name.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/twist/test/test_options.py