Convert tests to use pytest

[devos50]

We should convert the tests to use pytest, instead of nose.

[devos50]

@Solomon1732 this is something that's quite high on my wish list. If you're interested in learning more about pytest, you might want to start out with converting one or more tests (e.g., test_match_queue.py), using fixtures to reduce code duplication and to increase readability 👍

[Solomon1732]

I'll do it after the current PR 👍

[devos50]

I converted a few tests in #69

[dannysepler]

hi! i wrote a pip package to help out with this sort of refactor (https://github.com/dannysepler/pytestify) and i'm just snooping around github looking for people to test it out 🙃 -- totally cool if it doesn't end up working for you!