Patch tests in issue queues?
Patches uploaded on issues are automatically tested if they meet the right conditions which include:


not excluded based on name (described in description on upload field)
project has testing active
patch is again d6-8 banch


For core, testing is enabled; if you upload a patch against Drupal 7, for example, it will automatically be tested. For other projects, it can be enabled if you are a maintainer by looking at the "Issue" settings tab, there is a checkbox to enable testing.