This is currently a work in progress.
cd /Path/To/CodeIgniter4-Standard
Install dependencies (PHP_Codesniffer).
composer install
Verify PHP_Codesniffer works.
./vendor/bin/phpcs -i
Set installed standard to CodeIgniter4.
./vendor/bin/phpcs --config-set installed_paths /Path/To/CodeIgniter4-Standard/CodeIgniter4
Verify the CodeIgniter4 standard is installed.
./vendor/bin/phpcs -i
Run unit tests.
./vendor/bin/phpunit --debug --filter CodeIgniter4