TDD for legacy code, graphics code, and legacy graphics code?
We're currently undergoing a push to do more 'Agile testing' at work. At CCP, we "do" Agile pretty well, but I don't think we "code" Agile really well. A large part (the largest part?) of Agile coding and Agile testing is TDD/Unit Testing, of which I'm a huge fan if not an experienced practitioner.
I know how to do TDD for what I do; that is, side-by-side replacement of an internal legacy codebase in a high-level language. What I don't have experience in is TDD for expansion and maintenance of a huge, high performance, very active, legacy codebase, and specifically the graphics components and the C++ bits.
So if you have experience in these sorts of things, I'd love to hear them.
At this point I'm sticking my neck out as a TDD and unit testing advocate studio-wide, but am reluctant to evangelize too strongly outside of my areas of expertise. I don't think it'd be fair to the very talented people in those areas, and I also don't want to be wrong, even if I know I'm right :) So I'd really like to hear about your experiences with TDD and unit testing in the games and graphics space, and on legacy codebases, because people are coming to me with questions and I don't have good answers. I'd love to give them places to turn, articles to read, people to contact.
Thanks for any help.