Instead of keeping Python 3.9 in the list and manually skipping it in every session, it is cleaner to remove it from UNIT_TEST_PYTHON_VERSIONS entirely. Note that dropping support for Python 3.9 is a breaking change; per repository rules, this should be handled with a minor version bump rather than a patch to allow for continued support of the previous environment. Additionally, Python 3.14 should be included in the versions list as it is a valid version for this repository.

    "3.10",
    "3.11",
    "3.12",
    "3.13",
    "3.14",
]

Can't do until the global github actions config is updated.

The dependencies bigframes and geopandas were removed from the Python 3.10 test session. Since 3.10 is now the minimum supported version, these extras should continue to be tested to ensure compatibility. If they were moved elsewhere, please clarify; otherwise, they should be restored to maintain test coverage.

    "3.10": [
        "bqstorage",
        "bigframes",
        "geopandas",
    ],

This is intentional. We need a minimimal set of extras so that the minimum versions of dependencies can be properly tested.

This skip block is unnecessary if Python 3.9 is removed from the UNIT_TEST_PYTHON_VERSIONS list.

This skip block is unnecessary if Python 3.9 is removed from the UNIT_TEST_PYTHON_VERSIONS list.

Adding pyopenssl as a mandatory dependency is a significant change, as it requires C extensions and is generally not needed for Python 3.10+. Could you explain why this is now required for all users? If it's only needed for specific edge cases, consider making it an optional extra.

Several unit tests fail without this change. Note that it is a required dependency in later versions of google-auth, anyway.