## Technicalities
-Development on the latest version of Python is preferred. As of this writing it's 3.8.
+Development on the latest version of Python is preferred. As of this writing it's 3.9.
You can use any operating system. I am using macOS myself and CentOS at work.
Install all development dependencies using:
-```
+```console
$ pipenv install --dev
$ pipenv shell
$ pre-commit install
`pip install pipenv` in the virtualenv you're already using and invoke the command above
from the cloned _Black_ repo. It will do the correct thing.
-Before submitting pull requests, run tests with:
+Non pipenv install works too:
+
+```console
+$ pip install -r test_requirements
+$ pip install -e .[d]
+```
+
+Before submitting pull requests, run lints and tests with the following commands from
+the root of the black repo:
+
+```console
+# Linting
+$ pre-commit run -a
+
+# Unit tests
+$ tox -e py
+
+# Optional Fuzz testing
+$ tox -e fuzz
+
+# Optional CI run to test your changes on many popular python projects
+$ black-primer [-k -w /tmp/black_test_repos]
+```
+
+### News / Changelog Requirement
+`Black` has CI that will check for an entry corresponding to your PR in `CHANGES.md`. If
+you feel this PR not require a changelog entry please state that in a comment and a
+maintainer can add a `skip news` label to make the CI pass. Otherwise, please ensure you
+have a line in the following format:
+
+```md
+- `Black` is now more awesome (#X)
```
-$ python setup.py test
+
+To workout X, please use
+[Next PR Number](https://ichard26.github.io/next-pr-number/?owner=psf&name=black). This
+is not perfect but saves a lot of release overhead as now the releaser does not need to
+go back and workout what to add to the `CHANGES.md` for each release.
+
+### Style Changes
+
+If a change would affect the advertised code style, please modify the documentation (The
+_Black_ code style) to reflect that change. Patches that fix unintended bugs in
+formatting don't need to be mentioned separately though.
+
+### Docs Testing
+
+If you make changes to docs, you can test they still build locally too.
+
+```console
+$ pip install -r docs/requirements.txt
+$ pip install [-e] .[d]
+$ sphinx-build -a -b html -W docs/ docs/_build/
```
+## black-primer
+
+`black-primer` is used by CI to pull down well-known _Black_ formatted projects and see
+if we get source code changes. It will error on formatting changes or errors. Please run
+before pushing your PR to see if you get the actions you would expect from _Black_ with
+your PR. You may need to change
+[primer.json](https://github.com/psf/black/blob/master/src/black_primer/primer.json)
+configuration for it to pass.
+
+For more `black-primer` information visit the
+[documentation](https://github.com/psf/black/blob/master/docs/black_primer.md).
+
## Hygiene
If you're fixing a bug, add a test. Run it first to confirm it fails, then fix the bug,