JP-3986 - Add tests for persistence step

[stscirij]

Addresses JP-3986

This PR adds some unit tests to the persistence step

Tasks

• If you have a specific reviewer in mind, tag them.
• add a build milestone, i.e. Build 12.0 (use the latest build if not sure)
• Does this PR change user-facing code / API? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see changelog readme for instructions)
  • update or add relevant tests
  • update relevant docstrings and / or docs/ page
  • start a regression test and include a link to the running job (click here for instructions)
    • Do truth files need to be updated ("okified")?
      • after the reviewer has approved these changes, run okify_regtests to update the truth files
• if a JIRA ticket exists, make sure it is resolved properly

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.92%. Comparing base (eb19846) to head (d3a7047).
⚠️ Report is 686 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9419      +/-   ##
==========================================
+ Coverage   77.39%   77.92%   +0.53%     
==========================================
  Files         362      362              
  Lines       36220    36279      +59     
==========================================
+ Hits        28031    28269     +238     
+ Misses       8189     8010     -179     

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[stscirij]

Regression test run here:
https://github.com/spacetelescope/RegressionTests/actions/runs/14764710034

[emolter]

The codecov report for this PR shows the unit test coverage for persistence.py increasing from 7% to 27%. This is good progress, but 27% is still very low compared to other modules - the repository average is somewhere around 75%.

There are still a large number of methods that don't have any coverage: compute_decay, delta_fcn_capture, predict_saturation_capture, predict_ramp_capture, predict_capture, get_decay_param, get_capture_param, compute_slope, get_parameters, do_all. See https://app.codecov.io/gh/spacetelescope/jwst/pull/9419/blob/jwst/persistence/persistence.py.

[melanieclarke]

The codecov report for this PR shows the unit test coverage for persistence.py increasing from 7% to 27%. This is good progress, but 27% is still very low compared to other modules - the repository average is somewhere around 75%.

I think it would probably help a lot to get at least one unit test that runs the whole step on synthetic input. That should exercise the most code with the least effort.

[emolter]

The new test brings persistence.py up to 80%: https://app.codecov.io/gh/spacetelescope/jwst/pull/9419/blob/jwst/persistence/persistence.py

It may be worth checking whether some options could be toggled on and off with a test parametrization as some additional low-hanging fruit. But I certainly won't be the one to hold up this PR since this is now above the repository average.

Not sure how to dismiss my own review... do I need maintainers privileges?

Comments addressed

[melanieclarke]

This is a huge improvement in test coverage - between the unit tests and the new regtest, this module will be covered at 84%. Thanks for addressing this technical debt!

It looks like there are a couple minor comments still to address - a question from Pey Lian about the testing precision, and a request to remove the change log - but I think this is is looking good.

[melanieclarke]

LGTM. Thanks!