def test_with_context_calls_underlying(self):
        with startAction(action_type="parent"):
            wrapped = preserve_context(self.add)
            self.assertEqual(wrapped(3, y=4), 7)
If run inside an Eliot context, the result of C{preserve_context} is
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_action.py/PreserveContextTests.test_with_context_calls_underlying