It's also very easy to write some quick C code to chuck out test results in the format that Test::Harness expects. You can then have a normal *.t script fire it off and get your C tests integrated into your Perl test suite.

I wonder if that's more difficult than it sounds. I seem to recall that there's a lot of special case code in the Test:: modules to deal with VMS quirks (and a quick grep confirms this). I suppose I could just forget about VMS, but I don't like that thought. Have you any experience with this?