Add missing documentation to the test module

Proposed changes

The testing module currently lacks documentation in several classes. This pull request adds the missing documentation to improve clarity and maintainability

Types of changes

What types of changes does your code introduce to this project? Put an x in the boxes that apply

[ ] Bugfix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
[x] Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

[x] I have read the CONTRIBUTING.md
[x] I have added tests that prove my fix is effective or that my feature works
[x] I have added necessary documentation (if appropriate)

OneLiteFeatherNET / Microtus