'L{task.react} handles when the reactor is stopped and the
returned L{Deferred} doesn\'t fire.'

def test_asynchronousStop(self):

    def main(reactor):
        reactor.callLater(1, reactor.stop)
        return defer.Deferred()
    r = _FakeReactor()
    exitError = self.assertRaises(SystemExit, task.react, main, [], _reactor=r)
    self.assertEqual(0, exitError.code)
