Pytest Style: test_persistence.py

[utkbansal]

Fixes #

Changes made in this Pull Request:

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

[utkbansal]

@kain88-de Have a look at test_unpickle_missing in TestAtomGroupPickle. That case fails. I think that has something to do with del not working with fixtures?

[richardjgowers]

This needs removing

[utkbansal]

I haven't cleaned this up because the tests are still failing. Need to fix that first.

[orbeckst]

I don't think that del makes sense with these fixtures.

Try not to pass them as arguments and leave out the del lines. Maybe they never appear... but in this case, I have no idea what the deep pytest magic actually does.

You should also be able to remove the gc.collect() call.

[richardjgowers]

So the del might not be playing nice with the fixtures, but it's essential to the test. These tests are trying to see what happens when a Universe goes out of scope (is deleted and garbage collected).

[orbeckst]

You might be able to leave out the fixtures and then not need to explicitly del them – if pytest only creates the fixture for each method.

[richardjgowers]

@utkbansal fot the tests which rely on del on a Universe, try rewriting these to not use a fixture, but instead just put the setup inside the test method and see if it starts working again.

[utkbansal]

@richardjgowers The test does work that way. But it's a hack.

[richardjgowers]

@utkbansal the test relies on the Universe becoming garbage collected, so I think having the fixture hold a reference to the Universe is breaking the test. I can't really see a way round a fixture providing an object but not retaining a reference to it.

[utkbansal]

@richardjgowers Anything left here?