Which CI solution and testing framework?

I’m looking for a continuous integration solution for my Rails
projects. Need something that works with Subversion, assume that’s

Some projects use RSpec, others Test::Unit. We’ve also been
considering Shoulda. Due to lack of discipline and CI our test suites
tend to suck, and starting over would probably be a good thing for
most of our apps…
I also think that fixtures, which we use extensively, make for lousy
tests, and that mocking is the way to go.

Suggestions? Thoughts about which test/mocking framework to choose?