Remove stale python filterwarnings and skipped tests

[mroeschke]

Description

• Removes and improves some filterwarnings used in unit tests
• Removes test_magics_cpu as it's been perpetually skipped without resolution

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 3e316aaf-a183-4c78-bcfd-912dbf73254a

📥 Commits

Reviewing files that changed from the base of the PR and between 5967cc2 and eb23385.

📒 Files selected for processing (11)

• python/cudf/cudf/tests/input_output/test_feather.py
• python/cudf/cudf/tests/input_output/test_hdf5.py
• python/cudf/cudf/tests/input_output/test_json.py
• python/cudf/cudf/tests/series/test_binops.py
• python/cudf/cudf/tests/test_doctests.py
• python/cudf/cudf/tests/test_flags.py
• python/cudf/cudf_pandas_tests/_magics_cpu_test.py
• python/cudf/cudf_pandas_tests/test_magics.py
• python/cudf/pyproject.toml
• python/dask_cudf/dask_cudf/tests/test_distributed.py
• python/dask_cudf/dask_cudf/tests/test_groupby.py

💤 Files with no reviewable changes (5)

• python/cudf/cudf/tests/series/test_binops.py
• python/cudf/cudf/tests/input_output/test_json.py
• python/cudf/pyproject.toml
• python/cudf/cudf_pandas_tests/_magics_cpu_test.py
• python/cudf/cudf/tests/input_output/test_feather.py

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📝 Walkthrough

Summary by CodeRabbit

• Tests

  • Refactored test warning filters to use pytest decorators instead of inline suppression across multiple test modules.
  • Removed deprecated "Strings are not yet supported" warning filters.
  • Removed CPU-specific IPython magic test function.

• Chores

  • Updated copyright years in test files.
  • Removed unused pytest marker and botocore deprecation warning filter from configuration.

Walkthrough

This PR consolidates warning handling across cudf and dask_cudf test suites by migrating from inline warning suppression to pytest decorators, refactoring doctest filters from global to targeted, removing obsolete warnings, and cleaning up unused test markers and configurations. Copyright years are updated to 2026.

Changes

Warning Filter Consolidation and Test Configuration Cleanup

Layer / File(s)	Summary
I/O Test Warning Filter Updates python/cudf/cudf/tests/input_output/test_feather.py, python/cudf/cudf/tests/input_output/test_hdf5.py, python/cudf/cudf/tests/input_output/test_json.py	Feather, HDF5, and JSON reader tests switch from suppressing "Strings are not yet supported" to "Using CPU" warnings via pytest.mark.filterwarnings. HDF5 copyright extended to 2026.
Doctest Warning Filter Migration to Per-Test Targeting python/cudf/cudf/tests/test_doctests.py	Global FutureWarning suppression is removed and replaced with a marks_for_doctests mapping that applies targeted pytest.mark.filterwarnings to specific doctests by name during collection via pytest.param wrapping. Doctest skipping logic is removed.
Flag Test Decorator Migration and Deprecation Warning Removal python/cudf/cudf/tests/test_flags.py, python/cudf/cudf/tests/series/test_binops.py	test_set_flags_copy_true_makes_deep_copy migrates from inline warnings.catch_warnings() to @pytest.mark.filterwarnings decorator for pandas copy deprecation suppression. test_binop_index_dt_td_series_with_names DeprecationWarning suppression decorator is removed.
Magics Test Copyright Update and Import Cleanup python/cudf/cudf_pandas_tests/test_magics.py	Copyright year extended to 2023-2026. Unused os import is removed after CPU magics test code deletion.
dask_cudf Test Decorator Refactoring python/dask_cudf/dask_cudf/tests/test_distributed.py, python/dask_cudf/dask_cudf/tests/test_groupby.py	test_ucx_seriesgroupby and test_unique migrate from inline warnings.catch_warnings() to @pytest.mark.filterwarnings decorators for Port warning suppression. Unused warnings import removed from test_groupby.py.
pytest Configuration Cleanup python/cudf/pyproject.toml	botocore datetime.datetime.utcnow() deprecation warning filter removed from filterwarnings. Unused no_copy_on_write marker removed from markers allowlist.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested labels

Python, cudf.pandas

Suggested reviewers

• TomAugspurger
• bdice
• vyasr
• msarahan
• brandon-b-miller

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main purpose of the changeset: removing stale filterwarnings and skipped tests across multiple test files.
Description check	✅ Passed	The description is directly related to the changeset, explaining that filterwarnings are being removed/improved and the skipped test_magics_cpu is being removed.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[mroeschke]

/merge