Increase test coverage

[NullHypothesis]

Test coverage is almost zero at this point, which means that there's quite a bit of code that has never been executed.

[frankcash]

I would be interested in helping with this, do you have a preferred starting point?

[NullHypothesis]

Great, thanks for your interest, Frank! There's some rudimentary code in unittests.py which would be a good starting point. There are several functions in the code (e.g., in util.py) that are easy to test in isolation. For others, it might be more difficult.

[frankcash]

okay, awesome. I'll start by adding tests to unittests.py