pytest 6 - Anthony Sottile

About this Episode

pytest 6 is out. Specifically, 6.0.1, as of July 31.

And there's lots to be excited about.
Anthony Sottile joins the show to discuss features, improvements, documentation updates and more.

Full release notes / changelog

Some of what we talk about:

• How to update (at least, how I do it)
  • Run your test suites with 5.4.3 or whatever the last version you were using
  • Update to 6
  • Run again. Same output? Probably good.
  • If there are any warnings, maybe fix those.
  • You can also run with pytest -W error to turn warnings into errors.
  • Then find out all the cool stuff you can do now
• New Features
  • pytest now supports pyproject.toml files for configuration.
    • but remember, toml syntax is different than ini files. mostly quotes are needed
  • pytest now includes inline type annotations and exposes them to user programs.
    • Most of the user-facing API is covered, as well as internal code.
  • New command-line flags --no-header and --no-summary
  • A warning is now shown when an unknown key is read from a config INI file.
    • The --strict-config flag has been added to treat these warnings as errors.
  • New required_plugins configuration option allows the user to specify a list of plugins, including version information, that are required for pytest to run. An error is raised if any required plugins are not found when running pytest.
• Improvements
  • You can now pass output to things like less and head that close the pipe passed to them.
    • thank you!!!
  • Improved precision of test durations measurement.
    • use --durations=10 -vv to capture and show durations
  • Rich comparison for dataclasses and attrs-classes is now recursive.
  • pytest --version now displays just the pytest version,
    • while pytest --version --version displays more verbose information including plugins.
  • --junitxml now includes the exception cause in the message XML attribute for failures during setup and teardown.
• Improved Documentation
  • Add a note about --strict and --strict-markers and the preference for the latter one.
  • Explain indirect parametrization and markers for fixtures.
• Bug Fixes
• Deprecations
• Trivial/Internal Changes
• Breaking Changes you might need to care about before upgrading
  • PytestDeprecationWarning are now errors by default.
    • Check the deprecations and removals page if you are curious.
  • -k and -m internals were rewritten to stop using eval(), this results in a few slight changes but overall makes them much more consistent
  • testdir.run().parseoutcomes() now always returns the parsed nouns in plural form.
    • I'd say that's an improvement

Episode Links

• pytest Changelog / Release Notes
• Deprecations and Removals — pytest documentation