Small refactoring of tests

[KulaginVladimir]

Proposed changes

This PR introduces some modification to tests. Linked to #530.

Some information was added to the descripton of tests and several specific tests were parametrised.

Types of changes

What types of changes does your code introduce to FESTIM?

• 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)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

Checklist

• Black formatted
• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

Since there are a lot of modifications at the moment, I decided to show them in order to get a proper understanding of changes appropriateness.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.49%. Comparing base (dfec377) to head (682a902).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #726   +/-   ##
=======================================
  Coverage   99.48%   99.49%           
=======================================
  Files          58       58           
  Lines        2350     2358    +8     
=======================================
+ Hits         2338     2346    +8     
  Misses         12       12           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[RemDelaporteMathurin]

Thanks @KulaginVladimir we needed this clean up!