Something that is very cumbersome (and boring) to do for every developer out there is the software testing. To combat that, you usually develop a number of methods that helps you track down bugs, for example automatic bug-reports and unit-testing.
One of the more interesting ones is automated testing. For games, this usually means that you have a system that simulates the player and automatically generates input for it. For my latest project Hyena. I’ve had the rare opportunity to play around with an application where the controls are so basic that it was actually possible to write a system that played the whole game for me.