Add test coverage

[pandemicsyn]

Stemming from #8 (Update to support job executions), which included a small refactor to also allow implementing some basic tests, we should now add test coverage.

Should be pretty straightforward and relatively low weight (2) with most of the task mainly consisting of setting up repo scaffolding and the gh workflow. Ordinarily we would have done it as part of #8 but as we were pressed for time we've punted on adding test coverage.