HACKING.md

In this guide:

• Guidance for maintainers of the rules
  • Add test cases for a rule
  • Run all test cases
  • Run selected test cases
• Guidance for maintainers of the testing code

Guidance for maintainers of the rules

See first: Introduction to Vale rule development

Add test cases for a rule

Make sure that the rule has suitable test cases in tests/data/manifest.yml.

Run all test cases

We recommend that you first install uv. To install uv on Ubuntu:

sudo snap install astral-uv --classic

To run the test cases for every rule:

• If uv is installed

  make -C tests run
  

• If uv is not installed

  cd tests
  python3 -m venv .venv
  . .venv/bin/activate
  pip install -e .
  make run
  

Run selected test cases

Behind the scenes, we're using pytest to run each test case.

To run the test cases for a particular rule, such as 003-Ubuntu-names-versions:

• If uv is installed

  uv run --directory tests pytest -vv -k 003
  

• If uv is not installed

  # (Provided the working dir is 'tests' and the virtual environment is active)
  pytest -vv -k 003
  

Guidance for maintainers of the testing code

The code in the tests directory uses Python with pytest. We require the code to be well-formatted and pass static checks.

Our tools of choice are:

• ruff for formatting and checking code conventions
• pyright for checking types

If you've already installed ruff, you should be able to use it in the tests directory with no trouble. pyright is less straightforward, as it needs to be run in a virtual environment that contains the testing code's dependencies.

Instead of manually running these tools, we strongly recommend that you install uv and use make in the tests directory.

Command	Purpose
make format	Use ruff to format the testing code
make lint	Use ruff to check code conventions and pyright to check types
make run	Use pytest to run the test cases for every rule