Quick feedback on development progress is one of the key aspects of running short iterations. We need to know quickly when we are not on track and we need to verify quickly that we are back on track when the problem is solved. We need to be certain that a particular part of the specification is implemented and that later changes have not corrupted the functionality. Manual inspections and and verifications take too much time and resources and inhibit the development process.
We need to make the process of verifying specifications cheap, quick and efficient. Automating the verification of acceptance tests is the key to this. With automated acceptance tests, we can easily verify that the specifications are implemented. We have at our disposal acceptance testing tools that allow us to automate tests but still keep test descriptions human readable so that we can use them for later discussion.