So, the test I would add is:

```py
    def test_retry_value_is_decodable(self):
        """Ensure that from_dict is the inverse of to_dict when retry options
        are given.
        """
        from furious.async import Async

        async_job = Async("something",
                          task_args={'retry_options': {'task_retry_limit': 5}})
        new_async_job = Async.from_dict(async_job.to_dict())

        # Maybe there's a better way to test this?
        self.assertEqual(new_async_job.to_dict(), async_job.to_dict())

```