Partial improvement of test class names

[2319bli]

Description

Part of #6625.
I have partially changed instances of test classes with the generic name Test to a more detailed name.

Checklist

Important

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• Included a What's New entry
• Incorporated type hints in any changed code
• Checked if tests need updating
• Checked if benchmarks need updating
• Checked if documentation needs updating
  • Docstrings (we love code examples!)
  • User Manual pages
• Checked if dependencies need updating
• Confirmed that the GitHub 'checks' on this PR are passing ✅
  (further reading)

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[ukmo-ccbunney]

Splendid stuff - thanks @2319bli. 👍🏼
That will significantly improve the readability of the pytest output. 💯
LTGM! 🚀

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.15%. Comparing base (03489e8) to head (f8ad8dd).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7190   +/-   ##
=======================================
  Coverage   90.15%   90.15%           
=======================================
  Files          91       91           
  Lines       24990    24990           
  Branches     4687     4687           
=======================================
  Hits        22529    22529           
  Misses       1683     1683           
  Partials      778      778           

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