## Technicalities
-Development on the latest version of Python is preferred. As of this writing it's 3.9.
-You can use any operating system.
+Development on the latest version of Python is preferred. You can use any operating
+system.
-Install all development dependencies using:
+Install development dependencies inside a virtual environment of your choice, for
+example:
```console
-$ pipenv install --dev
-$ pipenv shell
-$ pre-commit install
-```
-
-If you haven't used `pipenv` before but are comfortable with virtualenvs, just run
-`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.
-
-Non pipenv install works too:
-
-```console
-$ pip install -r test_requirements
-$ pip install -e .[d]
+$ python3 -m venv .venv
+$ source .venv/bin/activate
+(.venv)$ pip install -r test_requirements.txt
+(.venv)$ pip install -e .[d]
+(.venv)$ pre-commit install
```
Before submitting pull requests, run lints and tests with the following commands from
```console
# Linting
-$ pre-commit run -a
+(.venv)$ pre-commit run -a
# Unit tests
-$ tox -e py
+(.venv)$ 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]
+(.venv)$ tox -e fuzz
```
### News / Changelog Requirement
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.
+formatting don't need to be mentioned separately though. If the change is implemented
+with the `--preview` flag, please include the change in the future style document
+instead and write the changelog entry under a dedicated "Preview changes" heading.
### 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/
+(.venv)$ pip install -r docs/requirements.txt
+(.venv)$ pip install [-e] .[d]
+(.venv)$ 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](./gauging_changes.md#black-primer).
-
## Hygiene
If you're fixing a bug, add a test. Run it first to confirm it fails, then fix the bug,