(Policy) Improved unit tests and addition of code coverage requirements

[mOctave]

Something I've been wanting to do for a while is to greatly improve the code coverage of the tests in this repo, since although almost everything works as expected now, I'd like to be able to know for sure if new changes break anything before releases. So, I'm planning to introduce a new policy:

• The current general-purpose tests (currently mislabelled as "unit tests") will be kept but relabelled as "TestIntegration.java" and "test_integration.py" (with corresponding class renames) which more accurately reflects their role
• All newly added classes and methods other than getters and setters must be accompanied by thorough tests
• Getters and setters need not be tested, more complicated accessor and mutator methods should be
• The structure of the tests should mirror the structure of the main files, with class/file names of TestX or test_x and method names exactly matching the methods in the main files
• Similar tests should be added for all pre-existing code
• Code coverage tools should be added to the codebase to ensure that a minimum of 80% code coverage is maintained
• As soon as possible, GH actions should be used to enforce these rules automatically

If you have anything to say about this, speak now or forever hold your peace, since the first round of changes will probably drop in the next 24 hours.