Add tests for PRs

[KarenJewell]

Integration tests?

Or otherwise e.g. if adding new scraper, check:

• Script is already called in Github Actions
• Output is already handled in mergedata.py
• Additional package dependencies needed for GH Actions

[JackGilmore]

Just to add to this, I think it would be a good idea to add a pre-flight check flag to the pipeline to allow it to run but then not commit the results to GitHub.

This would let us test any changes we make when adding new scripts/features during dev work on the pipeline. We could also use it to do a test run of the script on a Friday morning to make sure it runs without crashing before the current live run that happens at mid-day.

[gavbarnett]

I'll look at adding python tests (pytest), as part of the refactoring. #122 I'll probably do that first based on how much refactoring there needs done 😆