JP-3777: Select first and last groups in ramp fitting

[stscirij]

Added a unit test and updated docs

Resolves JP-3777

Closes #8872

This PR addresses JP-3777. It enables users to select firstgroup and lastgroup parameters when performing
ramp fitting. It works by setting the DO_NOT_USE bit in the GROUPDQ extension for groups outside the selected range.
Added a unit test and updated the docs.

Tasks

• request a review from someone specific, to avoid making the maintainers review every PR
• add a build milestone, i.e. Build 11.3 (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 below for change types)
  • 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")? No
      • 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

news fragment change types...

• changes/<PR#>.general.rst: infrastructure or miscellaneous change
• changes/<PR#>.docs.rst
• changes/<PR#>.stpipe.rst
• changes/<PR#>.datamodels.rst
• changes/<PR#>.scripts.rst
• changes/<PR#>.fits_generator.rst
• changes/<PR#>.set_telescope_pointing.rst
• changes/<PR#>.pipeline.rst

stage 1

• changes/<PR#>.group_scale.rst
• changes/<PR#>.dq_init.rst
• changes/<PR#>.emicorr.rst
• changes/<PR#>.saturation.rst
• changes/<PR#>.ipc.rst
• changes/<PR#>.firstframe.rst
• changes/<PR#>.lastframe.rst
• changes/<PR#>.reset.rst
• changes/<PR#>.superbias.rst
• changes/<PR#>.refpix.rst
• changes/<PR#>.linearity.rst
• changes/<PR#>.rscd.rst
• changes/<PR#>.persistence.rst
• changes/<PR#>.dark_current.rst
• changes/<PR#>.charge_migration.rst
• changes/<PR#>.jump.rst
• changes/<PR#>.clean_flicker_noise.rst
• changes/<PR#>.ramp_fitting.rst
• changes/<PR#>.gain_scale.rst

stage 2

• changes/<PR#>.assign_wcs.rst
• changes/<PR#>.badpix_selfcal.rst
• changes/<PR#>.msaflagopen.rst
• changes/<PR#>.nsclean.rst
• changes/<PR#>.imprint.rst
• changes/<PR#>.background.rst
• changes/<PR#>.extract_2d.rst
• changes/<PR#>.master_background.rst
• changes/<PR#>.wavecorr.rst
• changes/<PR#>.srctype.rst
• changes/<PR#>.straylight.rst
• changes/<PR#>.wfss_contam.rst
• changes/<PR#>.flatfield.rst
• changes/<PR#>.fringe.rst
• changes/<PR#>.pathloss.rst
• changes/<PR#>.barshadow.rst
• changes/<PR#>.photom.rst
• changes/<PR#>.pixel_replace.rst
• changes/<PR#>.resample_spec.rst
• changes/<PR#>.residual_fringe.rst
• changes/<PR#>.cube_build.rst
• changes/<PR#>.extract_1d.rst
• changes/<PR#>.resample.rst

stage 3

• changes/<PR#>.assign_mtwcs.rst
• changes/<PR#>.mrs_imatch.rst
• changes/<PR#>.tweakreg.rst
• changes/<PR#>.skymatch.rst
• changes/<PR#>.exp_to_source.rst
• changes/<PR#>.outlier_detection.rst
• changes/<PR#>.tso_photometry.rst
• changes/<PR#>.stack_refs.rst
• changes/<PR#>.align_refs.rst
• changes/<PR#>.klip.rst
• changes/<PR#>.spectral_leak.rst
• changes/<PR#>.source_catalog.rst
• changes/<PR#>.combine_1d.rst
• changes/<PR#>.ami.rst

other

• changes/<PR#>.wfs_combine.rst
• changes/<PR#>.white_light.rst
• changes/<PR#>.cube_skymatch.rst
• changes/<PR#>.engdb_tools.rst
• changes/<PR#>.guider_cds.rst

[codecov]

Codecov Report

Attention: Patch coverage is 95.83333% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.49%. Comparing base (cbba455) to head (522da63).
Report is 34 commits behind head on main.

Files with missing lines	Patch %	Lines
jwst/ramp_fitting/ramp_fit_step.py	95.83%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9095      +/-   ##
==========================================
+ Coverage   78.23%   78.49%   +0.25%     
==========================================
  Files         505      505              
  Lines       46249    46852     +603     
==========================================
+ Hits        36183    36776     +593     
- Misses      10066    10076      +10     

Flag	Coverage Δ		*Carryforward flag
nightly	77.78% <ø> (-0.01%)	⬇️	Carriedforward from b2bdf9b

*This pull request uses carry forward flags. Click here to find out more.

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[kmacdonald-stsci]

Other than improving code coverage as @emolter suggests, it all looks good.

[kmacdonald-stsci]

I recommend moving this section of code to a function and calling that function conditioned on if firstgroup is not None or lastgroup is not None:.

[kmacdonald-stsci]

To improve test coverage, by creating the function above, a new test could be parametrize firstgroup and lastgroup and calling only the new function, ensuring code coverage during testing for various combinations of these new parameters, without having to fit ramps, testing only that the group DQ flags get set properly. Although, I still recommend keeping this test to ensure a basic ramp fit works as expected using these new parameters.

[stscirij]

I added a new parametrized test that tested that the appropriate warnings are emitted

[drlaw1558]

Tested and looks like this is working as expected to me; this will be a really helpful tool for instrument teams to study detector systematics in the ramps.