@withActionContext
    def test_addCallbacksRaisesAfterAddActionFinish(self):
        d = DeferredContext(Deferred())
        d.addActionFinish()
        self.assertRaises(AlreadyFinished, d.addCallbacks, lambda x: x,
                          lambda x: x)
After L{DeferredContext.addActionFinish} is called, additional calls to
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_twisted.py/DeferredContextTests.test_addCallbacksRaisesAfterAddActionFinish