'L{task.react} handles when the reactor is stopped just before the
returned L{Deferred} fires.'

def test_synchronousStop(self):

    def main(reactor):
        d = defer.Deferred()
        def stop():
            reactor.stop()
            d.callback(None)
        reactor.callWhenRunning(stop)
        return d
    r = _FakeReactor()
    exitError = self.assertRaises(SystemExit, task.react, main, [], _reactor=r)
    self.assertEqual(0, exitError.code)
