def test_withContextUnsetOnRaise(self):
        action = Action(MemoryLogger(), "", TaskLevel(level=[]), "")
        try:
            with action.context():
                1/0
        except ZeroDivisionError:
            pass
        else:
            self.fail("no exception")
        self.assertIs(currentAction(), None)
L{Action.conext().__exit__} unsets the action if the block raises an
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_action.py/ActionTests.test_withContextUnsetOnRaise