[steveklabnik]

You can run cucumber + selenium. I'm pretty sure selenium can run in headless mode (haven't turned it on yet, too fun to watch!)

[jbarnette]

This is useful for tightening the feedback loop. Using something like Autotest gives me near-instant feedback on changes I'm making to client-side libraries.

I'll continue to periodically run my tests inside a "real" browser, but I think this sort of headless testing is a real win.

[Disclaimer: I wrote Johnson, so I'm not exactly a disinterested bystander. Edited for repetition.]