@withActionContext
    def test_addBothCallsAddCallbacks(self):
        result = Deferred()
        context = DeferredContext(result)
        called = []
        def addCallbacks(callback, errback,
                         callbackArgs=None, callbackKeywords=None,
                         errbackArgs=None, errbackKeywords=None):
            called.append((callback, errback, callbackArgs, callbackKeywords,
                           errbackArgs, errbackKeywords))
        context.addCallbacks = addCallbacks
        f = lambda x, y, z: None
        context.addBoth(f, 2, z=3)
        self.assertEqual(called, [(f, f, (2,), {"z": 3}, (2,), {"z": 3})])
L{DeferredContext.addBoth} passes its arguments on to
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_twisted.py/DeferredContextTests.test_addBothCallsAddCallbacks