def test_defaultReactor(self):
        """
        L{twisted.internet.reactor} is used if no reactor argument is passed to
        L{task.react}.
        """
        def main(reactor):
            self.passedReactor = reactor
            return defer.succeed(None)

        reactor = _FakeReactor()
        with NoReactor():
            installReactor(reactor)
            exitError = self.assertRaises(SystemExit, task.react, main, [])
            self.assertEqual(0, exitError.code)
        self.assertIs(reactor, self.passedReactor)

        L{twisted.internet.reactor} is used if no reactor argument is passed to
        L{task.react}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_task.py