So far in my experience, good design does far more to help maintain velocity than tests. In most applications I've been stuck on, the tests ended up being an i

So far in my experience, good design does far more to help maintain velocity than tests. In most applications I've been stuck on, the tests ended up being an impediment to development -- because the design was poor. The tests helped to reveal dependencies, so people who were working on bits of code could easily identify what dependencies they had to fix when they made changes, but that also served to underscore how badly coupled the various components were. I guess the moral is that too many mediocre wannabe agilistas try to use testing to cover up bad design.