Don’t use pytest plugins by default

Sometimes, when a new version of pytest, flake8 or isort is released, we get
new problems. Sometimes the bug is quickly fixed, sometimes it ends in drama
(I’m looking at you, tholo/pytest-flake8#87).

Pytest, flake8 and isort are robust tools, and we’d like to continue to use
them and to install them as testing dependencies.

Let’s lauch the tools without Pytest. We keep their configuration in
pyproject.toml so that users who want to use them in their editors can benefit
from the default tweaks. We remove the default pytest options so that packagers
don’t have to edit or remove pyproject.toml, and only have to install
pytest (linting is useless for packaging). We install pytest-xdist to launch
our tests in parallel for the CI.

.github/workflows/tests.yml

@@ -42,6 +42,10 @@ jobs:
       - name: Upgrade pip and setuptools
         run: python -m pip install --upgrade pip setuptools
       - name: Install tests’ requirements
-        run: python -m pip install .[test]
+        run: python -m pip install .[test] pytest-xdist
       - name: Launch tests
-        run: python -m pytest
+        run: python -m pytest -n auto
+      - name: Check coding style
+        run: python -m flake8
+      - name: Check imports order
+        run: python -m isort . --check --diff

docs/contribute.rst

@@ -42,13 +42,21 @@ Tests
 -----
 
 Tests are stored in the ``tests`` folder at the top of the repository. They use
-the `pytest`_ library.
+the pytest_ library.
 
-You can launch tests (with code coverage and lint) using the following command::
+You can launch tests using the following command::
 
   venv/bin/python -m pytest
 
+WeasyPrint also uses isort_ to check imports and flake8_ to check the coding
+style::
+
+  venv/bin/python -m isort . --check --diff
+  venv/bin/python -m flake8
+
 .. _pytest: https://docs.pytest.org/
+.. _isort: https://pycqa.github.io/isort/
+.. _flake8: https://flake8.pycqa.org/
 
 
 Documentation

pyproject.toml

@@ -52,18 +52,14 @@ Donation = 'https://opencollective.com/courtbouillon'
 
 [project.optional-dependencies]
 doc = ['sphinx', 'sphinx_rtd_theme']
-# TODO: remove the flake8 dependency when https://github.com/tholo/pytest-flake8/issues/87 is fixed
-test = ['pytest', 'pytest-xdist', 'pytest-flake8', 'pytest-isort', 'pytest-cov', 'coverage[toml]', 'flake8 <5']
+test = ['pytest', 'isort', 'flake8']
 
 [project.scripts]
 weasyprint = 'weasyprint.__main__:main'
 
 [tool.flit.sdist]
 exclude = ['.*']
 
-[tool.pytest.ini_options]
-addopts = '--isort --flake8 --numprocesses=auto'
-
 [tool.coverage.run]
 branch = true
 include = ['tests/*', 'weasyprint/*']