sharing test fixtures across subfolders is causing stdatamodels dowstream tests to fail

[emolter]

#9402 added some test fixtures that are used in jwst/datamodels/utils/tests as well as in jwst/combine_1d/tests and jwst/pipeline/tests. This construction is breaking the downstream tests for stdatamodels.

==================================== ERRORS ====================================
_ ERROR collecting .tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/combine_1d/tests/test_combine1d.py _
ImportError while importing test module '/home/runner/work/stdatamodels/stdatamodels/.tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/combine_1d/tests/test_combine1d.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.11.12/x64/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/combine_1d/tests/test_combine1d.py:7: in <module>
    from jwst.datamodels.utils.tests.test_wfss_multispec import wfss_multiexposure, wfss_spec3_multispec, example_spec, N_SOURCES
E   ModuleNotFoundError: No module named 'jwst.datamodels.utils.tests'
_ ERROR collecting .tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/pipeline/tests/test_calwebb_spec3.py _
ImportError while importing test module '/home/runner/work/stdatamodels/stdatamodels/.tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/pipeline/tests/test_calwebb_spec3.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.11.12/x64/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.tox/py311-jwst-cov-xdist/lib/python3.11/site-packages/jwst/pipeline/tests/test_calwebb_spec3.py:9: in <module>
    from jwst.datamodels.utils.tests.test_wfss_multispec import wfss_multiexposure, wfss_spec3_multispec, example_spec
E   ModuleNotFoundError: No module named 'jwst.datamodels.utils.tests'

[melanieclarke]

I missed that we were importing fixtures in the other PR - that does tend to cause problems. Better practice is to make the content of the fixture an importable and callable function, then make a lightweight fixture that calls it, local to the test that needs it.

[melanieclarke]

But also it probably does need a __init__ file.

[emolter]

why is it bad practice? Would an acceptable solution be to make the fixtures have a larger scope, e.g. session scope, instead?

[melanieclarke]

It's just not how pytest was designed to work -- it wants to discover fixtures itself rather than have you import them. It does kind of work, but you have to import any fixtures the one you're trying to use depends on, which I find confusing.

No, I don't think it would help to make them session scope -- what if you tried to run one of the tests where the fixture wasn't local by itself, and the fixture hadn't been created yet?

The other recommended solution is to make shared fixtures discoverable in a conftest somewhere above all the tests that need it. Since the ones you need are shared across top-level modules, they would have to be all the way at the top of the package, which I prefer not to do unless it's a really widely used fixture. For something specific like this, better to make functions you can import where needed.

[emolter]

ok thanks for the explanation