CPAN Testers also test on different operating system versions. And hence also test the Perl binaries, for a lot of different versions, by literally running the

CPAN Testers also test on different operating system versions. And hence also test the Perl binaries, for a lot of different versions, by literally running the combined test suites for all of the (public) Perl code. I really, really don't get why this isn't copied to the rest of the open source language environments. (Masochism? :-) )