Write unit tests

[mdchia]

Consider writing some unit tests (perhaps in a separate tests.py?) to establish that functions with clear input -> output expectations work to specification. Most functions probably don't need tests, but things involving math or string processing might (e.g. checking that Mac/Linux style paths and Windows style paths run the same for all path-based functions).

[mdchia]

Also noting that if you need additional libraries for unit testing, build an additional test-requirements.txt (or similar) to avoid unnecessary libraries in user deployments.

[samwiseg113-bot]

Done:

• Testing Framework
• test-requirements.txt
• load_data tests
• pipeline tests

TODO:

• Report tests
• Visualisation tests
• workflow tests
• UI tests (if needed?)