json data for/in python unittests

I'm writing an ORM-like library for Mongo. I've written some models, and want to make sure that they and the machinery that supports them are correct, so I'd like to write unit tests for them. I figured the best way to do that would be to simply write out some test data as JSON, then pass them to my models and see if the valid data is considered valid and the invalid data as invalid.

My question is where to put that data: it seems like a lot of non-TestCase stuff to put in test_models.py, but adding a separate test_data_for_models.json contributes its own headaches (versioning, etc.)

Which is the more recommended/idiomatic? Bear in mind I don't really need to generate any data--I'll likely just adapt data that's already in the db--I'm just unsure where to put it.