CI/TST: Enable -W error:::pandas in pytest during CI runs

[mroeschke]

In order to avoid introducing a warning originating from pandas that may be unwanted/false positive in another part of the API (#48397), the test suite should run with -W error:::pandas to error such that they can be addressed. This will also help reduce the noise in the test run logs.

Might be good to add this all the way in pyproject.toml in adopts.

[phofl]

Sounds good! But we have a bunch of warnings right now we have to fix before enabling this

[theoniko]

Hello all,
could i work on it? If yes, could you please give some hints which files to change?
Is sth like adding addopts = "-W error:::pandas" as in https://docs.pytest.org/en/6.2.x/customize.html#pyproject-toml

[phofl]

We have to fix the warnings before we can enable this. You have to run all tests to determine where the warnings are shown

[mroeschke]

Agreed, a good first step would be to catch or fix the tests where the warnings appear. Specifically you can view the logs of test runs in the CI and address the test warnings that appear e.g: https://github.com/pandas-dev/pandas/actions/runs/3558958743/jobs/5977992575

[theoniko]

Just to be sure, do you refer to the warnings like DeprecationWarning, FutureWarning and PerformanceWarning in the following sections in the log:

• 2022-11-27T17:26:05.2922016Z =============================== warnings summary ===============================
• 2022-11-27T17:34:18.8852922Z =============================== warnings summary ===============================

or something different?

[mroeschke]

Yeah exactly

[theoniko]

How shall i fix /home/runner/micromamba/envs/test/lib/python3.8/site-packages/botocore/httpsession.py:41: DeprecationWarning: 'urllib3.contrib.pyopenssl' module is deprecated and will be removed in a future release of urllib3 2.x. Read more in this issue: urllib3/urllib3#2680 since it is from another python module?

[jorisvandenbossche]

@theoniko that's a warning that is generated by an external package, not by pandas itself. The goal here of this issue to ensure we have no warnings of pandas itself (and error for this if it happens, to ensure our own tests don't generate warnings).

Now, also for external warnings, it is nice if they get fixed or suppressed (if we can't fix them ourselves in the tests).