Migration Pytests each load sim data separately

[eagmon]

This takes up a lot of the pytest runtime, with each process's test loading sim_data over again. One solution would be to have a single test that loads the sim_data, and then passes it into each of the individual process tests. The only reservation I have about this is that it would be one big test rather than many small tests.

[1fish2]

Would it suffice to load sim_data in a setUpClass class method or a setUpModule function, then use it in a bunch of test methods? Those are unittest features supported by pytest. pytest fixtures add more ways to do things. (Pytest has tons of features and extensibility.) https://docs.pytest.org/en/6.2.x/fixture.html