From Tim Bunce's Perl 5 Myths talk: Perl 5.10.0 has 78,883 core tests.
Ruby has about 1,400.
So Perl 5 core test suite has about 50 times as many tests as Ruby. So who has the testing culture again? It's not entirely a fair comparison because it's not asserting how many features each language has, but I doubt that Ruby is so feature poor to justify Perl having more than 50 tests for every 1 of Ruby's.
Hello, core Ruby developers! You've got an awesome language there. Could you start testing, please? Your community seems to do OK. Why not you?