Test versioning provides the ability to save auto-numbered versions of your tests as your team makes changes. Test versioning also includes a roll back function, so you can review your test versions and select any previous version to be used as the current version. Test versioning is controlled by a security setting, so to turn it on, go to > Setup > Security > Security Groups, Manage Security Rights, and enable versioning for the desired team members.
Pass around test runs allows your testers to wrap up test runs started by other team members. You can change the assigned to on the tests within a test set or within the run. When one tester pauses the run, another tester can grab it and continue.