Since Date::Holidays is loading modules I was looking around to find out whether there was a module, which could do this better that I do it in my current implementation.
I fell over Module::Load, but apparently this was also on the TODO list of this module.
So I downloaded the source and had a look at it, after playing around with it for some time and looking at the code behind the Test::More module's use_ok, I actually got it to work, so I have mailed the my patch and tests to the author...