def test_receive_ack(self):
        self.tr.clear()
        init_outstanding_ack = self.proto.outstanding_ack
        self.proto.stringReceived(DUMMY_ACK)
        self.assertEqual(self.tr.value(), b"")
        self.assertEqual(self.proto.outstanding_ack - init_outstanding_ack, 1)
dataset/ETHPy150Open jdswinbank/Comet/comet/protocol/test/test_voeventbroadcaster.py/VOEventBroadcasterTestCase.test_receive_ack/swapped operands of `-`