Starter Kit: Unit Testing in TakeTwo repositories

### Background on the problem the feature will solve/improved user experience
Our code currently lacks unit testing, which is needed for test driven development practices: easy debugging, functional testing, etc.

### Describe the solution you'd like
Provide unit tests for various TakeTwo repositories:

- [ ] https://github.com/Call-for-Code-for-Racial-Justice/TakeTwo-Marker-ChromeExtension
- [ ] https://github.com/Call-for-Code-for-Racial-Justice/TakeTwo-DataScience/
- [ ] https://github.com/Call-for-Code-for-Racial-Justice/taketwo-webapi/

### Tasks
- [ ] research existing tests of similar code bases
- [ ] document list of tests to be implemented for each repository based on programming language, architecture, etc
- [ ] create Github issues for each test in the appropriate repo and link to this issue as well
- [ ] implement changes in each repository as appropriate

### Acceptance Criteria

- [ ] At least 60% code coverage by unit tests

Begin by reviewing the three linked repositories: TakeTwo-Marker-ChromeExtension, TakeTwo-DataScience, and taketwo-webapi, along with existing tests in comparable codebases. Document the tests needed for each repository, create linked issues in the appropriate repositories, and use those issues to track implementation. Done means each repository has the planned unit tests and the combined work reaches at least 60% code coverage.

Vom Indexierungsmodell aus dem Issue-Text verfasst.