We finally have the Mason level tests running. I'm going to consolidate all of our main testing programs into one testing program that will run module, Mason, or Web tests from one simple command line interface. Everything will run transparently except for the need to pass a '-M' switch if I want the Web tests to be driven directly through Mason instead of the Web server. Already we're encountering bugs in the Mason code that were not previously diagnosed due to the lack of tests for them.
I also have a small program that spiders through the Web site and builds tests stubs for every page it finds, thus allowing a shell of a test suite to be built from scratch without the need to manually write them for every page. We already have one other team that is migrating to Perl 5.8.2 and Mason 1.24 and they're anxious to start using the new tools.
With any degree of luck, we'll soon be able to do real performance and code coverage profiling by targeting Mason directly rather than on a module by module basis.