- We have a test instance at https://phab-01.wmflabs.org/ where you can
play as much as you want.
This instance is the puppetized test instance running on the labs puppet master.
It is supposed to be as much like production as possible to allow actual testing before making changes in prod.
Changes here should be made by uploading puppet changes to the role::phabricator::labs. I would not recommend playing manually with it or soon it will have manual hacks that need to be synced with prod again.
It's easy though to spin up phab-02 and how many we like (and there already existed phabricator-test project) where alpha testing can be done manually. you can simply fire up any number of new instances and apply the role, we added it to the wikitech "puppet groups" list you get when configuring an instance.