An iterative approach to acceptance-test definition is essential to keeping up on XP iterations. After iteration planning is the time to work on details visible to the customer, but leave those that aren't (how-to items) to test design and execution. Defining details of the acceptance tests is really defining the quality the customer expects of the system. The customer does not always want the highest-quality system. Producing the customer's desired level of quality when the team has a "higher" standard requires the distinction between internal and external quality. External quality is quality as measured by the customer. Internal quality is quality as measured by the programmers. Try these ideas out yourself in the following exercise. |