def test_installNonExistentReactor(self):
        """
        Test that L{reactors.installReactor} raises L{reactors.NoSuchReactor}
        when asked to install a reactor which it cannot find.
        """
        self.pluginResults = []
        self.assertRaises(
            reactors.NoSuchReactor,
            reactors.installReactor, 'somereactor')

        Test that L{reactors.installReactor} raises L{reactors.NoSuchReactor}
        when asked to install a reactor which it cannot find.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_application.py