Improve test coverage #29
Description
Currently the only tests are for the environment variable helpers.
We need to add tests around the core logic of parsing the github/gitlab events and conducting the deployment & aliasing.
This is extremely important as it will give us confidence when adding new features/improvements.
Also we'll have a reason to setup proper CI for our own pull requests.
I don't think too many tests are a bad thing, so if you feel like writing some please jump in!