I just read the documentation and I know exactly what this module is for; I can't say that for every module on the CPAN.
This module is for validating the output of your "Test Anything Protocol" script to make sure it adheres to the currently defined specification. Note that the author says it is "experimental", but I am certain if you need to check your TAP, this module will be useful.
This module works exactly as advertised. I'm not sure why someone gave it one star.
Actually, I do know why. People seem to think "I don't understand this, so it must be bad" and then give the module a 1-star rating.
If someone like Ovid releases a testing module, you should probably think twice before giving it one star. Your dislike of the module is probably related to your own ignorance, not that of the author. (Basically, there are a lot people that I've never heard of telling the best Perl developers in the world that their modules suck. While this is true from time to time, you should probably be careful and give these folks the benefit of the doubt. If you're not sure, keep your thoughts to yourself.)