There will be a couple of articles on testing published on Perl.com
shortly. Skud (from e-smith) is using real-world examples from her job. I don't know the exact status, but she expected to have the first one ready sometime this week.
If there are still questions after that, let me know, and I'll work up another article. (If you have specific questions about a chunk of code, drop me a message and I'll take a look at it.)
Update: Here's one article. I promise I'm not Skud; we've been seen in public in the same room.