Extreme Programming (XP)

Extreme Programming, or XP, started out as essentially a thought experiment of what would happen if good things were taken beyond their usual limits. One term for this is to crank the dials to 11, which comes from attempting to turn speakers beyond their regular limits on a one-to-ten scale. Here are a few questions XP asks:

• If shorter delivery timeframes (mini-waterfalls) are good, what if we just organize the work into iterations of two weeks or less, and deploy at least every three iterations? (This goal was later shortened to every iteration.)
• If working closely with customers is good, how about we have an on-site customer as a team member? (For remote teams, this would be an embedded team member who is a customer/decision-maker, as opposed to a requirements document.)
• If code reviews are good, how about we have a continuous code review, with pair programming all the time?
• If testing is good, how about we unit test before we write the...