Of course! Take a look at the tests for
Excel::Template or
DBM::Deep. It's very common to see a t/common.pm or t/lib/common.pm in CPAN distros or work distros. Even if it's just a bunch of functions that provide useful encapsulation around
File::Temp and similar things.
My criteria for good software:
- Does it work?
- Can someone else come in, make a change, and be reasonably certain no bugs were introduced?