This is a test environment based on Lando for testing the Pantheon launchcheck WP-CLI command that also powers the Pantheon Status checks in the dashboard.
wp_launch_check is installed as a submodule which -- while yucky -- allows development to be done on launchcheck within the environment.
Composer is used to manage plugins and themes within the WordPress environment (although it may be more desirable to test plugin/theme installation using WP-CLI) but not to manage WordPress core itself. Composer scripts for running wp_launch_check are included in the composer.json file.
Before you are able to run launchcheck you will need to setup your environment. You can run the composer launchcheck:init script to take care of this for you.
launchcheck:init also checks for the existence of jq on your system. Using jq is optional, but it can be helpful to more easily parse JSON output when using the --format=json flag in launchcheck commands, e.g. lando wp launchcheck config --format=json | jq.
You can omit the jq check and just run the install by using composer launchcheck:install instead.
It's possible you might need to install WordPress core before your Lando box will run properly. There's a composer script to help with this as well: composer install:wp. This runs a lando wp core install using the wp-config file in this repository and creates a site with an admin user named admin with the password of admin.
Once the Composer dependencies of wp_launch_check are installed (see the installation steps above), you can run the launchcheck command in this environment normally using lando wp launchcheck. (This is because the wp_launch_check/vendor/autoload.php file is included in the wp-config.php file.) To see a full list of commands, run lando wp help launchcheck.
Some launchcheck commands can output their data in JSON syntax using the --format=json flag. If you have jq installed, you can pipe the output to jq to have the JSON pretty-printed, e.g. lando wp launchcheck config --format=json | jq.