Have you seen http://hypothesis.readthedocs.org/en/latest/examples.html#fu... ? It doesn't test very much - mostly just that the API doesn't produce a 500 error - but it's a decent example of how you can generate structured data with some constraints. http://hypothesis.readthedocs.org/en/latest/examples.html#co... is also a decent example where the data is more uniform but requires a bunch of massaging to satisfy the constraints.