Noel Llopis (Games from Within) and Sean Houghton, Backwards Is Forward: Making Better Games with Test-Driven Development:
> One of the questions we had when we jumped into TDD is
> whether it was going to hold for high-level code. We had
> seen in practice from previous projects that we can
> certainly do TDD to create low-level and intermediate-level
> libraries (math, collision, messaging, etc). But would it
> really work for high-level code that would build on
> low-level code?
>
> The answer is an unconditional yes. We have developed a
> full codebase doing TDD from the start, and we had no
> difficulty writing high-level code with TDD. Things like
> character state machines, game flow, or specific game
> entities were done through TDD without any problems, and
> greatly benefited from the TDD approach.
Noel’s blog is great, and this paper is being presented at the 2006 Game Developers Conference.
Noel and High Moon Studios have been a lot of pioneering work using Extreme Programming in the game development space. Game development can definitely make good use of Extreme Programming to manage the development process, dramatically improve the quality of code, and do wonders for scheduling accuracy and schedule predictability.
Extreme Programming in game development also presents special challenges due to the exploratory nature of a lot of the work, as well as the highly-interactive nature of the software itself. As Noel points out, you wind up writing much more finely-factored code when doing TDD, which will be alien to a lot of game developers but will help greatly with maintenance, debugging, and the ever-more-important portability. (Not just between Windows and Mac OS X, but also between Xbox and PlayStation 2 and Nintendo GameCube and Xbox 360 and PlayStation 3 and Nintendo Revolution…)