Why are a large number of tests a "Bad Thing"(tm)?
They become a bad thing when you have 157732 tests for 2245 lines of code. That is 70 tests per line of code, while of course a lot of lines don't even contain any logic. make test for Regexp::Common takes too long. I've already met a sysadmin who refused to install it because of that and I'm slowly becoming one myself.
if two pieces of code were in front of me and 1 passed 100 unique tests and the other 1000 unique tests, I'd be more confident initially with the latter
Of course, but do you really need thousands of tests for zipcodes? Are these thirty six thousand tests really needed for a palindrome regex?
Plus, don't you install each distribution only once in a while?
Yes, but I dislike this test suite that takes minutes to run for the same reason I dislike compiling from source. I am lazy and impatient and that is exactly why I like Perl.
There's only one thing regarding testing that I dislike more than an exaggerated test suite like Regexp::Common's and that is not having tests at all. I think R::C could do with only, say, a tenth or maybe a hundredth of its current test suite. For development, a huger one might be nice, but 1.5e5 tests on installation is more than I'd like.