The docs for WordPress-Coding-Standards assume that one is installing things globally, but I don’t like my hacking on phpcs to break my usage of it elsewhere, so I wanted to cordon things off in their own little dev area. This is how.
Clone the two required repositories to directories next to each other:
cd ~/public_html/wordpress/
git clone https://github.com/WordPress-Coding-Standards/WordPress-Coding-Standards.git
git clone https://github.com/squizlabs/PHP_CodeSniffer.git
Mostly you’ll be working from the PHP_CodeSniffer side of things. Change into that directory and set up its dependencies:
cd PHP_CodeSniffer
composer install
Set up phpcs so that it can find its tests and the WordPress coding standards:
cp phpunit.xml.dist phpunit.xml
./scripts/phpcs --config-set installed_paths ../WordPress-Coding-Standards/
And now you’re ready to run the tests (still from the PHP_CodeSniffer directory):
./vendor/bin/phpunit --filter WordPress