v9.0.0

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pytest 9.0.0 (2025-11-05)

New features

• #​1367:Support for subtests has been added.

  subtests <subtests> are an alternative to parametrization, useful in situations where the parametrization values are not all known at collection time.

  Example:

  defcontains_docstring(p:Path)->bool:"""Return True if the given Python file contains a top-level docstring."""    ...deftest_py_files_contain_docstring(subtests:pytest.Subtests)->None:forpathinPath.cwd().glob("*.py"):withsubtests.test(path=str(path)):assertcontains_docstring(path)

  Each assert failure or error is caught by the context manager and reported individually, giving a clear picture of all files that are missing a docstring.

  In addition,unittest.TestCase.subTest is now also supported.

  This feature was originally implemented as a separate plugin inpytest-subtests, but since then has been merged into the core.

  [!NOTE]
  This feature is experimental and will likely evolve in future releases. By that we mean that we might change how subtests are reported on failure, but the functionality and how to use it are stable.

• #​13743: Added support fornative TOML configuration files.

  While pytest, since version 6, supports configuration inpyproject.toml files under[tool.pytest.ini_options],
  it does so in an "INI compatibility mode", where all configuration values are treated as strings or list of strings.
  Now, pytest supports the native TOML data model.

  Inpyproject.toml, the native TOML configuration is under the[tool.pytest] table.

  # pyproject.toml[tool.pytest]minversion ="9.0"addopts = ["-ra","-q"]testpaths = ["tests","integration",]

  The[tool.pytest.ini_options] table remains supported, but both tables cannot be used at the same time.

  If you prefer to use a separate configuration file, or don't usepyproject.toml, you can usepytest.toml or.pytest.toml:

  # pytest.toml or .pytest.toml[pytest]minversion ="9.0"addopts = ["-ra","-q"]testpaths = ["tests","integration",]

  The documentation now (sometimes) shows configuration snippets in both TOML and INI formats, in a tabbed interface.

  Seeconfig file formats for full details.

• #​13823: Added a"strict mode" enabled by thestrict configuration option.

  When set totrue, thestrict option currently enables

  • strict_config
  • strict_markers
  • strict_parametrization_ids
  • strict_xfail

  The individual strictness options can be explicitly set to override the globalstrict setting.

  The previously-deprecated--strict command-line flag now enables strict mode.

  If pytest adds new strictness options in the future, they will also be enabled in strict mode.
  Therefore, you should only enable strict mode if you use a pinned/locked version of pytest,
  or if you want to proactively adopt new strictness options as they are added.

  Seestrict mode for more details.

• #​13737: Added thestrict_parametrization_ids configuration option.

  When set, pytest emits an error if it detects non-unique parameter set IDs,
  rather than automatically making the IDs unique by adding0,1, ... to them.
  This can be particularly useful for catching unintended duplicates.

• #​13072: Added support for displaying test sessionprogress in the terminal tab using theOSC 9;4; ANSI sequence.
  When pytest runs in a supported terminal emulator like ConEmu, Gnome Terminal, Ptyxis, Windows Terminal, Kitty or Ghostty,
  you'll see the progress in the terminal tab or window,
  allowing you to monitor pytest's progress at a glance.

  This feature is automatically enabled when running in a TTY. It is implemented as an internal plugin. If needed, it can be disabled as follows:

  • On a user level, using-p no:terminalprogress on the command line or via an environment variablePYTEST_ADDOPTS='-p no:terminalprogress'.
  • On a project configuration level, usingaddopts = "-p no:terminalprogress".

• #​478: Support PEP420 (implicit namespace packages) as--pyargs target whenconsider_namespace_packages istrue in the config.

  Previously, this option only impacted package imports, now it also impacts tests discovery.

• #​13678: Added a newfaulthandler_exit_on_timeout configuration option set to "false" by default to letfaulthandler interrupt thepytest process after a timeout in case of deadlock.

  Previously, afaulthandler timeout would only dump the traceback of all threads to stderr, but would not interrupt thepytest process.

  -- byogrisel.

• #​13829: Added support for configuration option aliases via thealiases parameter inParser.addini() <pytest.Parser.addini>.

  Plugins can now register alternative names for configuration options,
  allowing for more flexibility in configuration naming and supporting backward compatibility when renaming options.
  The canonical name always takes precedence if both the canonical name and an alias are specified in the configuration file.

Improvements in existing functionality

• #​13330: Having pytest configuration spread over more than one file (for example having both apytest.ini file andpyproject.toml with a[tool.pytest.ini_options] table) will now print a warning to make it clearer to the user that only one of them is actually used.

  -- bysgaist

• #​13574: The single argument--version no longer loads the entire plugin infrastructure, making it faster and more reliable when displaying only the pytest version.

  Passing--version twice (e.g.,pytest --version --version) retains the original behavior, showing both the pytest version and plugin information.

  [!NOTE]
  Since--version is now processed early, it only takes effect when passed directly via the command line. It will not work if set through other mechanisms, such asPYTEST_ADDOPTS oraddopts.

• #​13823: Addedstrict_xfail as an alias to thexfail_strict option,
  strict_config as an alias to the--strict-config flag,
  andstrict_markers as an alias to the--strict-markers flag.
  This makes all strictness options consistently have configuration options with the prefixstrict_.

• #​13700:--junitxml no longer prints thegenerated xml file summary at the end of the pytest session when--quiet is given.

• #​13732: Previously, when filtering warnings, pytest would fail if the filter referenced a class that could not be imported. Now, this only outputs a message indicating the problem.

• #​13859: Clarify the error message forpytest.raises() when a regexmatch fails.

• #​13861: Better sentence structure in a test's expected error message. Previously, the error message would be "expected exception must be <expected>, but got <actual>". Now, it is "Expected <expected>, but got <actual>".

Removals and backward incompatible breaking changes

• #​12083: Fixed a bug where an invocation such aspytest a/ a/b would cause only tests froma/b to run, and not other tests undera/.

  The fix entails a few breaking changes to how such overlapping arguments and duplicates are handled:

  1. pytest a/b a/ orpytest a/ a/b are equivalent topytest a; if an argument overlaps another arguments, only the prefix remains.
  2. pytest x.py x.py is equivalent topytest x.py; previously such an invocation was taken as an explicit request to run the tests from the file twice.

  If you rely on these behaviors, consider using--keep-duplicates <duplicate-paths>, which retains its existing behavior (including the bug).

• #​13719: Support for Python 3.9 is dropped following its end of life.

• #​13766: Previously, pytest would assume it was running in a CI/CD environment if either of the environment variables$CI or$BUILD_NUMBER was defined;
  now, CI mode is only activated if at least one of those variables is defined and set to anon-empty value.

• #​13779:PytestRemovedIn9Warning deprecation warnings are now errors by default.

  Following our plan to remove deprecated features with as little disruption as
  possible, all warnings of typePytestRemovedIn9Warning now generate errors
  instead of warning messages by default.

  The affected features will be effectively removed in pytest 9.1, so please consult the
  deprecations section in the docs for directions on how to update existing code.

  In the pytest9.0.X series, it is possible to change the errors back into warnings as a
  stopgap measure by adding this to yourpytest.ini file:

  [pytest]filterwarnings =    ignore::pytest.PytestRemovedIn9Warning

  But this will stop working when pytest9.1 is released.

  If you have concerns about the removal of a specific feature, please add a
  comment to13779.

Deprecations (removal in next major release)

• #​13807:monkeypatch.syspath_prepend() <pytest.MonkeyPatch.syspath_prepend> now issues a deprecation warning when the prepended path contains legacy namespace packages (those usingpkg_resources.declare_namespace()).
  Users should migrate to native namespace packages (420).
  Seemonkeypatch-fixup-namespace-packages for details.

Bug fixes

• #​13445: Made the type annotations ofpytest.skip and friends more spec-complaint to have them work across more type checkers.

• #​13537: Fixed a bug in whichExceptionGroup with onlySkipped exceptions in teardown was not handled correctly and showed as error.

• #​13598: Fixed possible collection confusion on Windows when short paths and symlinks are involved.

• #​13716: Fixed a bug where a nonsensical invocation likepytest x.py[a] (a file cannot be parametrized) was silently treated aspytest x.py. This is now a usage error.

• #​13722: Fixed a misleading assertion failure message when usingpytest.approx on mappings with differing lengths.

• #​13773: Fixed the static fixture closure calculation to properly consider transitive dependencies requested by overridden fixtures.

• #​13816: Fixedpytest.approx which now returns a clearer error message when comparing mappings with different keys.

• #​13849: Hidden.pytest.ini files are now picked up as the config file even if empty.
  This was an inconsistency with non-hiddenpytest.ini.

• #​13865: Fixed--show-capture with--tb=line.

• #​13522: Fixedpytester in subprocess mode ignored all :attr`pytester.plugins <pytest.Pytester.plugins>` except the first.

  Fixedpytester in subprocess mode silently ignored non-strpytester.plugins <pytest.Pytester.plugins>.
  Now it errors instead.
  If you are affected by this, specify the plugin by name, or switch the affected tests to usepytester.runpytest_inprocess <pytest.Pytester.runpytest_inprocess> explicitly instead.

Packaging updates and notes for downstreams

• #​13791: Minimum requirements oniniconfig andpackaging were bumped to1.0.1 and22.0.0, respectively.

Contributor-facing changes

• #​12244: Fixed self-test failures whenTERM=dumb.
• #​12474: Added scheduled GitHub Action Workflow to run Sphinx linkchecks in repo documentation.
• #​13621: pytest's own testsuite now handles thelsof command hanging (e.g. due to unreachable network filesystems), with the affected selftests being skipped after 10 seconds.
• #​13638: Fixed deprecatedgh pr new command inscripts/prepare-release-pr.py.
  The script now usesgh pr create which is compatible with GitHub CLI v2.0+.
• #​13695: Flushstdout andstderr inPytester.run to avoid truncated outputs intest_faulthandler.py::test_timeout on CI -- byogrisel.
• #​13771: Skiptest_do_not_collect_symlink_siblings on Windows environments without symlink support to avoid false negatives.
• #​13841:tox>=4 is now required when contributing to pytest.
• #​13625: Added missing docstrings topytest_addoption(),pytest_configure(), andcacheshow() functions incacheprovider.py.

Miscellaneous internal changes

• #​13830: Configuration overrides (-o/--override-ini) are now processed during startup rather than duringconfig.getini() <pytest.Config.getini>.