Parameterized testing

Parameterized Tests, Fixtures

I spent some time converting groups of similar tests to single parameterized tests. These tests work identically to their non-parameterized counterpoints, but they come with a lot less boilerplate / room for error.

Changes Made

• Grouped similar tests into single parameterized tests in database_management, user_io and schema.
• Replaced "constant" variables with fixtures - this ensures that tests run independently of the ones run before them.
• Wrote custom fixtures for simulated input and menu testing, in the new conftest.py file.
• General improvements / corrections to comments.
• Implemented a basic provider main menu, and a test file for provider.py. This was mostly just so that the menu test has something to test.

Test Plan

git pull

git checkout paramaterized_testing

make test

Checklist

• Code follows the project's coding style and conventions.
• Automated tests for the changes have been added or existing tests have been updated.
• Code coverage for new or modified code is maintained or improved.
• The code builds and runs without errors or warnings.
• Documentation has been updated to reflect the changes made.
• All discussions and feedback on the PR have been addressed.
• CI/CD pipelines pass successfully, including any required checks or tests.
• The PR has been reviewed and approved by the designated reviewers.

Additional Notes

Sorry about the large commit, but I think these'll be useful tools / examples for the rest of the team moving forward.