'stopStreaming() can be called more than once without blowing
up. This is useful for error-handling paths.'

def test_stopStreamingTwice(self):

    consumer = StringTransport()
    nsProducer = NonStreamingProducer(consumer)
    streamingProducer = _PullToPush(nsProducer, consumer)
    streamingProducer.startStreaming()
    streamingProducer.stopStreaming()
    streamingProducer.stopStreaming()
    self.assertTrue(streamingProducer._finished)
