* [behave test framework](https://behave.readthedocs.io) >= 1.2.5
* [phpunit](https://phpunit.de) >= 7.3
* [PHP CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer)
+* [Pylint](https://pylint.org/)
The documentation is built with mkdocs:
```sh
sudo apt install php-cgi phpunit php-codesniffer \
- python3-pip python3-setuptools python3-dev
+ python3-pip python3-setuptools python3-dev pylint3
pip3 install --user behave mkdocs
```