Hopefully, you've separated your Model code from your View code and your Controller code.

You can test your Model code using Test::* modules.

You can test your View code by simulating your Controller code and matching the web output captured as a string. Hopefully, you're smart enough to return strings rather than "print" everything. {grin}

Once those are verified, you can test your Controller code by firing up your app on a mini-server, and poking at it with WWW::Mechanize, driven by a Test::* script.

Yes, it takes more work to design a web app that is testable, but the consequences of not testing are clearly documented.