test: consolidate testing logic

[susnux]

Consolidate and de-duplicate tests.
Most of the previous tests were AI generated and AI is bad with checking if it can reuse existing logic.
So this cleans up the setup.

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.84%. Comparing base (3e63c39) to head (a421a88).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1750      +/-   ##
==========================================
+ Coverage   89.04%   89.84%   +0.79%     
==========================================
  Files          44       44              
  Lines        1132     1132              
  Branches      284      284              
==========================================
+ Hits         1008     1017       +9     
+ Misses         92       85       -7     
+ Partials       32       30       -2     

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.