Makes sense. But it does seem like a shift in position from the very "test-centric" view of XP. In the above link I don't see anything about "delete your tests

Makes sense. But it does seem like a shift in position from the very "test-centric" view of XP. In the above link I don't see anything about "delete your tests when not needed anymore", or did I miss it? How do you know when some tests are "not needed any more"? Isn't the idea of regression-testing to keep tests around so you know if any new code will break them? That should give you the "agility" to refactor your code, I think, is what the proponents of XP would say.