I do automated testing as much as I can, the main thing standing in my way is the problem of testing GUIs. GUI testing frameworks are inevitably painfully slow, don't test the appear of a GUI and don't test things like responsiveness and the varieties of behaviors of user message loop. I'd like to have the ability to test even more.

That said, I think TDD is trendy-consultant-crap. Writing a test before your write the code only works for simplistic code that doesn't need much testing and probably won't produce the right test for your code once you have written the code.

Also, for code I've just written, a ad-hoc manual test using the GUI is often much faster than writing a full test and I likely wouldn't ever need to run those tests again. The test suit takes quite a while to complete and if I could add every manual test I've ever run, it would take absolutely forever.

Something like "Zen Test", which runs the relevant tests in the background on code being changed sounds good but I don't think there's anything like it for c++. I'm a bit doubtful it could work on complex code in any language. A lot of R-and-R magic sounds like its creators never went code involving one model method, one controller method and one view method.