This is an extension for PHPStan that adds some rules based on the smells in the XUnit Patterns book by Gerard Meszaros.
To use this extension, require it in Composer:
composer require --dev xunitpatterns/xunitpatterns-stan
That is all you need to do if you have phpstan/extension-installer then that's all you need to do.
Otherwise, you will need to include the rules manually in your phpstan.neon file.