Rob Olson's blog
I like Autotest because it allows me to stay within my code editor and let my test suite run automatically in the background. After each run I get a nice, unobtrusive, growl notification informing me whether my most recent change caused the tests to fail or pass.
It used to be that setting up and configuring Autotest for the OS X with pretty growl notifications was a nontrivial task. I remember that I spent several hours getting it working a year ago. However, there has been several developments with Autotest in recent months that greatly simplify the process. One of those enhancements is that Autotest can now use FSEvent introduced in OS X Leopard so that it no longer has to continuously poll the filesystem. This has the advantage of vastly reducing Autotest's CPU usage when idle.