https://github.com/kunalb/PressTest - Unit testing framework for wordpress wrapping phpunit. It mocks out functions (by parsing the existing php files + plugin files you might have and generating stubs) unless you explicitly require them and makes it actually possible to write tests. Alpha a couple of years ago, not sure if it still works.

https://github.com/kunalb/PressTest/blob/master/screenshot-3... https://github.com/kunalb/PressTest/blob/master/screenshot-2... etc.