There are a number of ways you can help with Testopia.
If you find bugs you can report them at bugzilla.mozilla.org under product Testopia.
If you fix a bug, please attach a patch on the bug and request review.
We always need help documenting Testopia. Things such as installation (especially on non Linux systems), configuring, and using Testopia can be added to the wiki or submitted for inclusion in the docs.
In general, please follow the Bugzilla contributor guide at http://www.bugzilla.org/contribute/ when contributing to Testopia.
We welcome anyone and everyone who wishes to contribute.