According to that wiki, taps-testing - Testing .NET and Mono software using TAP has a yaml writer :D
Too bad it's .Net and won't help me ;)
See this thread JSON TAP Diagnostics? for some reasons why it probably doesn't exist :)
Well, that's the point I don't really understand. About 3 years ago there were a lot of discussions about adding this cool feature and since then nothing happened? I was under the impression that the whole testing infrastructure is one of Perl strengths with the Test:: and TAP:: modules, but in this area it looks like nothing is going on.
Don't get me wrong. I understand that most people working on CPAN modules are doing this in their free time and of course I'm not in the position to demand a particular module, but I just don't understand why this effort has stalled in the last 3 years. I'm hoping someone who participated in that original discussion will read this post :)