If you don't test your code, what makes you think it works?!

Here are some of my favourite modules for testing Perl code.

Type::Tiny has been knocking around in some shape or another for almost a year now. It's certainly grown a lot since its first commit. The distribution probably no longer merits the "Tiny" name, though the lead module itself is still fairly lean. There are over 80 distributions that list it as a pre-requisite in some way or another, and more still that depend on those.

So I think it's time to begin planning to stabalize the API. Right now, my plan is:

OK, so you've written your module like this:

package MyUtils;
use strict;
use warnings FATAL => qw( all );
sub frobnicate { ... }
1;

It passes its test suite, and all is fine and dandy. You use the frobnicate function in a long-running data processing script, and after the first 45 minutes it suddenly dies saying Use of uninitialized value $quux in addition at lib/MyUtils.pm line 13. D'oh!