The difference between a test case and a requirement is the moment of discovery
There are several straightforward ways to distinguish a test case from a requirement. A test case tells you how to check some kind of thing about the application, a requirement tells you that the application should do some kind of thing. A test case is written by a tester, a requirement by a business analyst. A test case takes the shape of an action and an evaluation of the result, a requirement takes the form of a sentence like “product ABC shall do XYZ.”1
A less straightforward, but more interesting way to distinguish a test case and a requirement, is this:
The difference between a test case and a requirement is the moment of discovery.2
In this post I want to explore the meaning of that statement. In the next post I’ll explore how looking at requirements and test cases in this way, can help us to do better testing. So this post will be a bit more philosophical, the next one more practical.