Every agile story should have a testable completion point, agreed upon by development and the customer. If whether or not the story is "done" is vague and argua

Every agile story should have a testable completion point, agreed upon by development and the customer. If whether or not the story is "done" is vague and arguable, it's not good enough to do. One of the big problems here, and where QA professionals can add real value, is defining that "done" point. Customers are often not very good at it. Their idea of what they want is too vague. They want developers to just build something, and they accept or reject it when they see it (and fault developers for not building it right). But really, all story completion criteria should be testable, and developers should be able to demonstrate the tests. The job of QA shouldn't be to test, but to make sure the developers are actually testing what they claim to test.