Remove the dead `cloudant_fake` module, or add its missing tests

[jroachgolf84]

Description

Module	Expected test file
providers/cloudant/src/airflow/providers/cloudant/cloudant_fake.py	providers/cloudant/tests/unit/cloudant/test_cloudant_fake.py

It is currently suppressed in the OVERLOOKED_TESTS allowlist in airflow-core/tests/unit/always/test_project_structure.py.

This is a scoped subset of the meta issue #35442, limited to the cloudant provider.

What should these tests cover?

Probably nothing, and that is the finding worth recording here. cloudant_fake.py defines two no-op stand-ins, CloudantV1 and CouchDbSessionAuthenticator, whose own docstrings describe them as a "Phony class to pass mypy when real class is not imported". Every method body is empty, so there is no behaviour a test could meaningfully assert.

More to the point, the module is dead. It existed to serve one conditional import in the hook:

if sys.version_info < (3, 10):
    from airflow.providers.cloudant.cloudant_fake import CloudantV1, CouchDbSessionAuthenticator
else:
    from ibmcloudant import CloudantV1, CouchDbSessionAuthenticator

That fallback was needed while ibmcloudant was excluded on Python 3.9, as recorded in the excluded-python-versions block that used to sit in providers/cloudant/provider.yaml. #52072 dropped Python 3.9 support, removed the version guard, and left the hook importing CloudantV1 and CouchDbSessionAuthenticator directly from ibmcloudant. The stub module was not removed with it.

A search across the repository now finds no import of airflow.providers.cloudant.cloudant_fake in any source, test, or configuration file. Its only remaining reference anywhere is its own entry in OVERLOOKED_TESTS.

So the sensible resolution is removal rather than new tests:

1. Delete providers/cloudant/src/airflow/providers/cloudant/cloudant_fake.py and drop its OVERLOOKED_TESTS entry.
2. If it turns out the module is deliberately retained for a mypy path that is not visible from the source, keep it and add a minimal test_cloudant_fake.py asserting both classes are constructible and that set_service_url accepts a URL, then drop the allowlist entry either way.

Option 1 looks correct given the history above, but it is worth a second opinion from anyone with context on the original optional-import arrangement before the file is deleted.

Definition of Done

1. Confirm whether cloudant_fake.py is still needed by anything.
2. Either delete the module, or add providers/cloudant/tests/unit/cloudant/test_cloudant_fake.py.
3. Remove the providers/cloudant/tests/unit/cloudant/test_cloudant_fake.py entry from OVERLOOKED_TESTS in airflow-core/tests/unit/always/test_project_structure.py
4. These should both pass, the second one confirming that nothing depended on the stub for typing:

breeze testing providers-tests providers/cloudant/tests/unit/cloudant

breeze run mypy providers/cloudant/src/airflow/providers/cloudant

---

Drafted-by: Claude Code (Opus 5); reviewed and edited by @jroachgolf84 before posting.

[jroachgolf84]

This is an issue that is reserved for the Airflow Summit "Contributors" Workshop. This is denoted with the label contributors-workshop. Out of respect for the organizers and participants of this workshop, please do not implement a PR that addresses this issue.

If this issue is still open following Airflow Summit, the label will be removed and the issue can be picked up.

[jroachgolf84]

This issue is now open for contribution. Please feel free to create a PR!