Using externally defined expected results

For some applications, users can articulate processing rules that describe the software's behavior. In other cases, the job of an analyst or a designer transforms the user's desires into procedural descriptions of the software.

In many cases, it's easier for users to provide concrete examples of expected results. For some business-oriented applications, the users may be more comfortable creating a spreadsheet that shows us sample inputs and expected results. Working from user-supplied, concrete sample data can simplify the developing software.

Whenever possible, have real users produce concrete examples of correct results. Creating procedural descriptions or software specifications is remarkably difficult. Creating concrete examples and generalizing from the examples to a software specification is less fraught with complexity and confusion. Further, it plays into a style of development where the test cases drive the development effort. Given a suite...