Remove 'slow_test' unittest marker

[snejus]

Remove slow_test unittest marker

Removes the slow_test decorator and its supporting SKIP_SLOW_TESTS env-var mechanism entirely. All previously "slow" test classes now run unconditionally.

Changes:

• Deletes slow_test() helper from beets/test/_common.py
• Removes all @_common.slow_test() usages across test files
• Updates CONTRIBUTING.rst to drop the SKIP_SLOW_TESTS documentation

Just doing some plumbing removing some unused noise from tests.

[github-actions]

Thank you for the PR! The changelog has not been updated, so here is a friendly reminder to check if you need to add an entry.

[Copilot]

Pull request overview

PR remove old slow_test unittest marker plumbing. Grug see goal is make test suite simpler by always running tests, and delete unused env-var skip path.

Changes:

• Remove slow_test() helper and its SKIP_SLOW_TESTS behavior from beets/test/_common.py.
• Drop @_common.slow_test() decorators across test modules (tests now run always).
• Remove SKIP_SLOW_TESTS docs from CONTRIBUTING.rst.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/ui/test_ui.py	Remove slow_test decorator from plugin-related test classes.
test/ui/commands/test_completion.py	Remove slow_test decorator from completion tests.
test/test_logging.py	Remove slow_test decorator and now-unused _common import.
test/test_importer.py	Remove slow_test decorator from importer test class.
test/test_dbcore.py	Remove slow_test decorator and now-unused _common import.
test/plugins/test_edit.py	Remove slow_test decorators and now-unused _common import.
test/plugins/test_convert.py	Remove slow_test decorators from convert-related test classes.
test/plugins/test_art.py	Remove slow_test decorator from art importer tests.
beets/test/_common.py	Delete slow_test() helper (and unittest import).
CONTRIBUTING.rst	Remove documentation for SKIP_SLOW_TESTS.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.77%. Comparing base (a4ad7d4) to head (ccdccdf).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6569   +/-   ##
=======================================
  Coverage   71.77%   71.77%           
=======================================
  Files         159      159           
  Lines       20528    20528           
  Branches     3264     3264           
=======================================
  Hits        14734    14734           
  Misses       5105     5105           
  Partials      689      689           

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[semohr]

Thanks!