Rails 3 + RSpec + Speed
Here’s a nice guide to getting RSpec tests running quickly (and automatically) on Rails 3, from Peter Cooper at Ruby Inside. I use RSpec every day and my tests already run pretty quickly, but anything that speeds things up even more is alright by me :)
As an aside, if you’re not using RSpec on Rails you really should look into it. And if you’re not running your tests automatically (and repeatedly) using something like autotest or watchr — both mentioned in Peter’s article — then I highly recommend doing doing just that to keep your code under control.