Modern Python CI with Coverage in 2025

1 comments

• dnouri 7 hours ago
  I covered a gap by blogging about: Modern Python CI with Coverage in #2025

  Let me know in the comments if you think it's useful.

  From the table of contents:

      Our toolchain
          py-cov-action: GitHub-native coverage
              The two-workflow pattern for fork PRs
          pytest-xdist: Parallel testing by default
          uv: Fast package management
      Six critical gotchas
          Gotcha #1: Using coverage run -m pytest with xdist
          Gotcha #2: Missing relative_files = true
          Gotcha #3: Hidden files excluded from artifacts
          Gotcha #4: Fork PRs can't post comments
          Gotcha #5: Missing pytest-cov plugin
          Gotcha #6: E2E tests with subprocesses contribute 0% coverage
      Complete working example
          .github/workflows/ci.yml
          .github/workflows/post-coverage-comment.yml
          pyproject.toml configuration
      Verifying your setup
          Check relative paths
          Verify artifact upload
          Test fork PR comments
          What success looks like
      Migration notes
          From Codecov/Coveralls
          From pip to uv
      Next steps
      Resources

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  • turtleyacht 7 hours ago
    Which packages or Actions would be used for mutation testing?
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    • dnouri 5 hours ago
      Interesting question. However, I haven't worked with those kinds of tests before.

      It looks like there's two pytest plugins at least to support you with that:

      - Mutatest: Python mutation testing: https://mutatest.readthedocs.io/

      - Mutagen: https://github.com/timpaquatte/pytest-mutagen

      Let me know how it goes.