bd45ccd2ca
pytest allows a fixture to request its own name (directly or
indirectly), in which case the fixture with the same name but one level
up is used.
To know which fixture should be used next, pytest keeps a mutable
item-global dict `_arg2index` which maintains this state. This is not
great:
- Mutable state like this is hard to understand and reason about.
- It is conceptually buggy; the indexing is global (e.g. if requesting
`fix1` and `fix2`, the indexing is shared between them), but actually
different branches of the subrequest tree should not affect each
other.
This is not an issue in practice because pytest keeps a cache of the
fixturedefs it resolved anyway (`_fixture_defs`), but if the cache is
removed it becomes evident.
Instead of the `_arg2index` state, count how many `argname`s deep we are
in the subrequest tree ("the fixture stack") and use that for the index.
This way, no global mutable state and the logic is very localized and
easier to understand.
This is slower, however fixture stacks should not be so deep that this
matters much, I hope.
.. image:: https://github.com/pytest-dev/pytest/raw/main/doc/en/img/pytest_logo_curves.svg
:target: https://docs.pytest.org/en/stable/
:align: center
:height: 200
:alt: pytest
------
.. image:: https://img.shields.io/pypi/v/pytest.svg
:target: https://pypi.org/project/pytest/
.. image:: https://img.shields.io/conda/vn/conda-forge/pytest.svg
:target: https://anaconda.org/conda-forge/pytest
.. image:: https://img.shields.io/pypi/pyversions/pytest.svg
:target: https://pypi.org/project/pytest/
.. image:: https://codecov.io/gh/pytest-dev/pytest/branch/main/graph/badge.svg
:target: https://codecov.io/gh/pytest-dev/pytest
:alt: Code coverage Status
.. image:: https://github.com/pytest-dev/pytest/actions/workflows/test.yml/badge.svg
:target: https://github.com/pytest-dev/pytest/actions?query=workflow%3Atest
.. image:: https://results.pre-commit.ci/badge/github/pytest-dev/pytest/main.svg
:target: https://results.pre-commit.ci/latest/github/pytest-dev/pytest/main
:alt: pre-commit.ci status
.. image:: https://www.codetriage.com/pytest-dev/pytest/badges/users.svg
:target: https://www.codetriage.com/pytest-dev/pytest
.. image:: https://readthedocs.org/projects/pytest/badge/?version=latest
:target: https://pytest.readthedocs.io/en/latest/?badge=latest
:alt: Documentation Status
.. image:: https://img.shields.io/badge/Discord-pytest--dev-blue
:target: https://discord.com/invite/pytest-dev
:alt: Discord
.. image:: https://img.shields.io/badge/Libera%20chat-%23pytest-orange
:target: https://web.libera.chat/#pytest
:alt: Libera chat
The ``pytest`` framework makes it easy to write small tests, yet
scales to support complex functional testing for applications and libraries.
An example of a simple test:
.. code-block:: python
# content of test_sample.py
def inc(x):
return x + 1
def test_answer():
assert inc(3) == 5
To execute it::
$ pytest
============================= test session starts =============================
collected 1 items
test_sample.py F
================================== FAILURES ===================================
_________________________________ test_answer _________________________________
def test_answer():
> assert inc(3) == 5
E assert 4 == 5
E + where 4 = inc(3)
test_sample.py:5: AssertionError
========================== 1 failed in 0.04 seconds ===========================
Due to ``pytest``'s detailed assertion introspection, only plain ``assert`` statements are used. See `getting-started <https://docs.pytest.org/en/stable/getting-started.html#our-first-test-run>`_ for more examples.
Features
--------
- Detailed info on failing `assert statements <https://docs.pytest.org/en/stable/how-to/assert.html>`_ (no need to remember ``self.assert*`` names)
- `Auto-discovery
<https://docs.pytest.org/en/stable/explanation/goodpractices.html#python-test-discovery>`_
of test modules and functions
- `Modular fixtures <https://docs.pytest.org/en/stable/explanation/fixtures.html>`_ for
managing small or parametrized long-lived test resources
- Can run `unittest <https://docs.pytest.org/en/stable/how-to/unittest.html>`_ (or trial)
test suites out of the box
- Python 3.8+ or PyPy3
- Rich plugin architecture, with over 850+ `external plugins <https://docs.pytest.org/en/latest/reference/plugin_list.html>`_ and thriving community
Documentation
-------------
For full documentation, including installation, tutorials and PDF documents, please see https://docs.pytest.org/en/stable/.
Bugs/Requests
-------------
Please use the `GitHub issue tracker <https://github.com/pytest-dev/pytest/issues>`_ to submit bugs or request features.
Changelog
---------
Consult the `Changelog <https://docs.pytest.org/en/stable/changelog.html>`__ page for fixes and enhancements of each version.
Support pytest
--------------
`Open Collective`_ is an online funding platform for open and transparent communities.
It provides tools to raise money and share your finances in full transparency.
It is the platform of choice for individuals and companies that want to make one-time or
monthly donations directly to the project.
See more details in the `pytest collective`_.
.. _Open Collective: https://opencollective.com
.. _pytest collective: https://opencollective.com/pytest
pytest for enterprise
---------------------
Available as part of the Tidelift Subscription.
The maintainers of pytest and thousands of other packages are working with Tidelift to deliver commercial support and
maintenance for the open source dependencies you use to build your applications.
Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use.
`Learn more. <https://tidelift.com/subscription/pkg/pypi-pytest?utm_source=pypi-pytest&utm_medium=referral&utm_campaign=enterprise&utm_term=repo>`_
Security
^^^^^^^^
pytest has never been associated with a security vulnerability, but in any case, to report a
security vulnerability please use the `Tidelift security contact <https://tidelift.com/security>`_.
Tidelift will coordinate the fix and disclosure.
License
-------
Copyright Holger Krekel and others, 2004.
Distributed under the terms of the `MIT`_ license, pytest is free and open source software.
.. _`MIT`: https://github.com/pytest-dev/pytest/blob/main/LICENSE