We here at Cat's Eye Technologies have decided to stop building new ad-hoc test suite machinery for every new esolang we implement in Haskell. Instead, we have put together a package that can be used and reused for this purpose, and we have (for reasons obscure even to us) called it Falderal. It doesn't do a lot yet (it's only version 0.1...), but it has promise. We're already using it in Quylthulg. To encourage contributions, its development is hosted on a public repository on Bitbucket. Watch for its use in future projects!
Check it out at http://catseye.tc/projects/falderal/