Convert test_netcdf to PyTest

[trexfeathers]

🚀 Pull Request

Description

This one was pretty tricky - a big file with lots of out-dated patterns!

I recommend reviewing each commit individually. Having to drop all the context managers (ad7c85d) meant unindenting a lot of lines, which confuses the rest of the 'narrative'.

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• benchmark_this Request that this pull request be benchmarked to check if it introduces performance shifts

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.95%. Comparing base (03c21c8) to head (ad7c85d).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6601   +/-   ##
=======================================
  Coverage   89.95%   89.95%           
=======================================
  Files          91       91           
  Lines       24447    24447           
  Branches     4567     4567           
=======================================
  Hits        21992    21992           
  Misses       1686     1686           
  Partials      769      769           

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[ESadek-MO]

Thanks @trexfeathers!

Passes the checklist run through, nothing stands out, good to go!