Software Testing

Automated testing is as simple as removing the "Manual Effort" and letting the computer do the thinking. This can be done with integrated debug tests, to much more intricate processes. The idea of the tests is to find bugs that are often very challenging or time intensive for human testers to find. This sort of testing can save many man hours and can be more "efficient" in some cases. But it will cost more to ask a developer to write more lines of code into the game (or an external tool) then it does to pay a tester and there is always the chance there is a bug in the bug testing program. Re-usability is another problem; you may not be able to transfer a testing program from one title (or platform) to another. And of course, there is always the "human factor" of testing that can never truly be replaced.
Other successful alternatives or variation: Nothing is infallible. Realistically, a moderate split of human and automated testing can rule out a wider range of possible bugs, rather than relying solely on one or the other. Giving the testers limited access to any automated tools can often help speed up the test cycle.