Add unit tests via pytest for functions - code coverage needed

[MikeLippincott]

Awesome to see a test for this! Consider organizing the function and the tests in distinct modules so they may be versioned and iterated upon quickly. An advantage here is that you'd also have a way to understand code coverage - that is, how much of the reusable work has been tested. One framework that can help with this is pytest, which enables you to consistently run tests together using a format similar to what you already have here.

For example:

├── src
│   └── utils.py
└── tests
    └── test_utils.py

Originally posted by @d33bs in #47 (comment)