Edward Hieatt's blog
At Pivotal Labs we take Continuous Integration (CI) seriously. Every project has a dedicated machine that serves as a CI environment. Each checkin on the project causes a build to be kicked off. A "build" means checking out the code from scratch and running of all the project's tests, which, for a Rails project, means unit and functional tests, JavaScript tests and Selenium tests. For the JavaScript and Selenium tests, we run multiple browsers on multiple OS's (e.g. IE 7 on Windows XP, FF 3 on OS X, etc).
We consider it critically important to keep each project's build green (i.e. successful) at all times. A build is the heartbeat of the project: if it's green, everything is healthy; if it turns red (i.e. fails), the team is encouraged to jump on the problem and get it back to green right away. We want red builds to go away quickly; the longer a build stays red, the longer it takes to track down the problem and the more likely it is that additional tests will be broken (the "broken windows effect").
In order to facilitate this level of discipline, we've learned over the years that making the status of our CI environments obvious and visible to the team is critical. If a team isn't acutely aware of the status of its build, it's unlikely that a red build will get noticed and fixed quickly. You can have the CI server email the team, but that doesn't work very well when the whole team is pairing all day: it might be a few hours before someone notices the email. You can install plugins in your browser or system tray that show build status, which helps, but still, they're not always obvious enough. The best way we've found to keep the team informed is to display the status of the build high on a wall near the team as a big red or green indicator. That way, even when you're busy coding, it's easy to notice the build going red. These days we use 2 wide screen TVs, positioned in the office so that one is easily seen from any developer station.
As Ian just posted, Pivotal Tracker won a Jolt award tonight. Here are some early pictures from the event.
The Jolt award for Pivotal Tracker
Edward with the Jolt award for Pivotal Tracker
Ian with the Jolt award for Pivotal Tracker