On the Continuous Development blog there's a new post showing how Olek Janiszewski came up with a solution to integrate PHPUnit and the Zend Framework via the watchr Ruby gem.

Whenever working on a Ruby project, I'd run autotest with test_notifier to get immediate feedback on my code. Unfortunately, I don't know a similar utility integrated with Zend Framework and PHPUnit. [...] My solution is not as well designed and portable as test_notifier, and it doesn't play as nicely with my Zend application as autotest does with RSpec and Rails. It’s more of a quick hack to cover my needs 80% of the time.

The watchr gem changes to the correct directory and runs the usual PHPUnit command (to run all tests) and then captures the output to display back to the client. You end up with messages like these: success, warning and fatal errors.