'Make sure signal caching sender receivers don\'t prevent garbage
collection of senders.'

def testCachedGarbagedCollected(self):

    class sender(object, ):
        pass
    wref = weakref.ref(sender)
    d_signal.connect(receiver_1_arg)
    d_signal.send(sender, val='garbage')
    del sender
    garbage_collect()
    try:
        self.assertIsNone(wref())
    finally:
        d_signal.disconnect(receiver_1_arg)
