That's exactly how I work (web development) and I am really happy with it so far. First, I am playing with a throw-away code to understand how I want it to be.

That's exactly how I work (web development) and I am really happy with it so far. First, I am playing with a throw-away code to understand how I want it to be. Then, I write some tests based on the acquired understanding and then finally working code. I can even copy-paste some parts of the throw-away code if they were correct initially. I see my designs being damaged by tests sometimes, though but in tolerable amounts, and I am happy to compromise.