There are many places in XP to seek a "step by step". This "Camp" word is reflected in the development process of XP. By testing to stabilize the path (completed function) that has already passed. Of course, this also includes testing for bugs.
However, unfortunately, testing is a violation of programmers; plus habits, therefore often waive testing because it is too lazy or negligent or difficult to find a better test. However, from the perspective of learning, when you encounter a test method, it is often the most advanced progress. Therefore, it is often that the system development is "step by step", and on the other hand, it has also improved the level of production testing.
"A thousand miles, destroyed in the ant hole, if there is a lazy or more difficult but negligent test, those missing tests will slowly spread slowly like the holes on the spider, until all testing efforts are destroyed once.
