XP day is here

Just at the start if another XP day. Just had a keynote from google on how they have developed internal tools and infrastructure to run and gather statistics on test runs on all of their projects.
Some interesting points
* Google invest $100m on testing and have calculated that they have saved $160m – I wonder if this scales down.
* Goolge have 10,000 devs and each team manages their own releases which come from HEAD.
* They have used the statistics gathered to develop heuristics for good unit tests and intend to publish these at some point along with tools