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There should probably be test suites to cover dependencies to ensure that all libraries are adequately in sync -- I'm not sure how easy this is to do in practice.

Hmmm. It's best done as the library is being written because it could actually help development and because the author likely has a better idea of what a function is supposed to do. But test suites are usually ignored or built long after the fact. Since quickcheck is quite easy to use, I wonder what's missing? Is it infrastructure (a handy driver program and some make targets) or some well-worked examples to cut and paste from? Where do I find examples of how to quickly add quickcheck to my library?

May I plug the GHC testsuite framework here? It's about 1k lines of Python (Makefiles are optional), copes with running tests multiple ways, has concepts of "expected failures" and "unexpected passes", and it generates a nice summary output at the end. It's quite configurable too. Take a look at fptools/testsuite/README in the GHC CVS tree. Cheers, Simon