How do I turn off print at home for the test environment? **self-hosted**

When we were self-hosted we did try setting up test emails (and even the website itself) to only be available on our internal network, but found that it limited the scope of our testing too much (and would have been a nightmare for us during the last year...)  Many of us work remotely now, and when we make big systemic changes or introduce new features we like to recruit community members to assist in our testing and give us feedback.