Contribution getting started¶
Contributions are highly welcomed and appreciated. Every little help counts, so do not hesitate!
Feature requests and feedback¶
Do you like pytest? Share some love on Twitter or in your blog posts!
We’d also like to hear about your propositions and suggestions. Feel free to submit them as issues and:
- Explain in detail how they should work.
- Keep the scope as narrow as possible. This will make it easier to implement.
Report bugs for pytest in the issue tracker.
If you are reporting a bug, please include:
- Your operating system name and version.
- Any details about your local setup that might be helpful in troubleshooting, specifically the Python interpreter version, installed libraries, and pytest version.
- Detailed steps to reproduce the bug.
If you can write a demonstration test that currently fails but should pass (xfail), that is a very useful commit to make as well, even if you cannot fix the bug itself.
Look through the GitHub issues for bugs.
Talk to developers to find out how you can fix specific bugs. To indicate that you are going to work on a particular issue, add a comment to that effect on the specific issue.
Don’t forget to check the issue trackers of your favourite plugins, too!
Look through the GitHub issues for enhancements.
Talk to developers to find out how you can implement specific features.
Pytest could always use more documentation. What exactly is needed?
- More complementary documentation. Have you perhaps found something unclear?
- Documentation translations. We currently have only English.
- Docstrings. There can never be too many of them.
- Blog posts, articles and such – they’re all very appreciated.
You can also edit documentation files directly in the GitHub web interface, without using a local copy. This can be convenient for small fixes.
Build the documentation locally with the following command:
$ tox -e docs
The built documentation should be available in the
Where ‘en’ refers to the documentation language.
Submitting Plugins to pytest-dev¶
Pytest development of the core, some plugins and support code happens
in repositories living under the
All pytest-dev Contributors team members have write access to all contained repositories. Pytest core and plugins are generally developed using pull requests to respective repositories.
The objectives of the
pytest-dev organisation are:
- Having a central location for popular pytest plugins
- Sharing some of the maintenance responsibility (in case a maintainer no longer wishes to maintain a plugin)
You can submit your plugin by subscribing to the pytest-dev mail list and writing a mail pointing to your existing pytest plugin repository which must have the following:
- PyPI presence with a
setup.pythat contains a license,
pytest-prefixed name, version number, authors, short and long description.
tox.inifor running tests using tox.
README.txtdescribing how to use the plugin and on which platforms it runs.
LICENSE.txtfile or equivalent containing the licensing information, with matching info in
- an issue tracker for bug reports and enhancement requests.
- a changelog
If no contributor strongly objects and two agree, the repository can then be
transferred to the
Here’s a rundown of how a repository transfer usually proceeds
(using a repository named
joedoe/pytest-xyz as example):
joedoetransfers repository ownership to
joedoeto both as maintainer.
calvintransfers repository to
pytest-devand configures team access:
pytest-dev/Contributors team has write access to all projects, and
every project administrator is in it. We recommend that each plugin has at least three
people who have the right to release to PyPI.
Repository owners can rest assured that no
pytest-dev administrator will ever make
releases of your repository or take ownership in any way, except in rare cases
where someone becomes unresponsive after months of contact attempts.
As stated, the objective is to share maintenance and avoid “plugin-abandon”.
Preparing Pull Requests¶
Fork the repository.
Enable and install pre-commit to ensure style-guides and code checks are followed.
masterfor bugfixes and doc changes.
featuresfor new features or functionality changes.
Follow PEP-8 for naming and black for formatting.
Tests are run using
tox -e linting,py37
The test environments above are usually enough to cover most cases locally.
changelog/2574.bugfix.rst, use issue id number and one of
trivialfor the issue type.
Unless your change is a trivial or a documentation fix (e.g., a typo or reword of a small section) please add yourself to the
AUTHORSfile, in alphabetical order.
What is a “pull request”? It informs the project’s core developers about the changes you want to review and merge. Pull requests are stored on GitHub servers. Once you send a pull request, we can discuss its potential modifications and even add more commits to it later on. There’s an excellent tutorial on how Pull Requests work in the GitHub Help Center.
Here is a simple overview, with pytest-specific bits:
Fork the pytest GitHub repository. It’s fine to use
pytestas your fork repository name because it will live under your user.
Clone your fork locally using git and create a branch:
$ git clone [email protected]:YOUR_GITHUB_USERNAME/pytest.git $ cd pytest # now, to fix a bug create your own branch off "master": $ git checkout -b your-bugfix-branch-name master # or to instead add a feature create your own branch off "features": $ git checkout -b your-feature-branch-name features
Given we have “major.minor.micro” version numbers, bugfixes will usually be released in micro releases whereas features will be released in minor releases and incompatible changes in major releases.
If you need some help with Git, follow this quick start guide: https://git.wiki.kernel.org/index.php/QuickStart
Install pre-commit and its hook on the pytest repo:
Note: pre-commit must be installed as admin, as it will not function otherwise:
$ pip install --user pre-commit $ pre-commit install
pre-commitwill run whenever you commit.
https://pre-commit.com/ is a framework for managing and maintaining multi-language pre-commit hooks to ensure code-style and code formatting is consistent.
Tox is used to run all the tests and will automatically setup virtualenvs to run the tests in. (will implicitly use http://www.virtualenv.org/en/latest/):
$ pip install tox
Run all the tests
You need to have Python 3.7 available in your system. Now running tests is as simple as issuing this command:
$ tox -e linting,py37
This command will run tests via the “tox” tool against Python 3.7 and also perform “lint” coding-style checks.
You can now edit your local working copy and run the tests again as necessary. Please follow PEP-8 for naming.
You can pass different options to
tox. For example, to run tests on Python 3.7 and pass options to pytest (e.g. enter pdb on failure) to pytest you can do:
$ tox -e py37 -- --pdb
Or to only run tests in a particular test module on Python 3.7:
$ tox -e py37 -- testing/test_config.py
pre-commitwill re-format the files if necessary.
If instead of using
toxyou prefer to run the tests directly, then we suggest to create a virtual environment and use an editable install with the
$ python3 -m venv .venv $ source .venv/bin/activate # Linux $ .venv/Scripts/activate.bat # Windows $ pip install -e ".[testing]"
Afterwards, you can edit the files and run pytest normally:
$ pytest testing/test_config.py
Commit and push once your tests pass and you are happy with your change(s):
$ git commit -a -m "<commit message>" $ git push -u
Create a new changelog entry in
changelog. The file should be named
<issueid>.<type>.rst, where issueid is the number of the issue related to the change and type is one of
trivial. You may not create a changelog entry if the change doesn’t affect the documented behaviour of Pytest.
Add yourself to
AUTHORSfile if not there yet, in alphabetical order.
Finally, submit a pull request through the GitHub website using this data:
head-fork: YOUR_GITHUB_USERNAME/pytest compare: your-branch-name base-fork: pytest-dev/pytest base: master # if it's a bugfix base: features # if it's a feature
Writing tests for plugins or for pytest itself is often done using the testdir fixture, as a “black-box” test.
For example, to ensure a simple test passes you can write:
def test_true_assertion(testdir): testdir.makepyfile( """ def test_foo(): assert True """ ) result = testdir.runpytest() result.assert_outcomes(failed=0, passed=1)
Alternatively, it is possible to make checks based on the actual output of the termal using glob-like expressions:
def test_true_assertion(testdir): testdir.makepyfile( """ def test_foo(): assert False """ ) result = testdir.runpytest() result.stdout.fnmatch_lines(["*assert False*", "*1 failed*"])
When choosing a file where to write a new test, take a look at the existing files and see if there’s
one file which looks like a good fit. For example, a regression test about a bug in the
should go into
test_cacheprovider.py, given that this option is implemented in
If in doubt, go ahead and open a PR with your best guess and we can discuss this over the code.
Joining the Development Team¶
Anyone who has successfully seen through a pull request which did not require any extra work from the development team to merge will themselves gain commit access if they so wish (if we forget to ask please send a friendly reminder). This does not mean your workflow to contribute changes, everyone goes through the same pull-request-and-review process and no-one merges their own pull requests unless already approved. It does however mean you can participate in the development process more fully since you can merge pull requests from other contributors yourself after having reviewed them.