One of the new features in the upcoming PHPUnit 3.1 release is the support for distributed testing through the ability to log test result and code coverage data to a database. This way, the same test suite can be run on different platforms with the results being aggregated in the database. For this to work, however, we need a key in the database that identifies test runs from different machines as being related. A Subversion revision number is a perfect candidate for this.
He includes a sample script that helps with the storage of the results in the database by grabbing a unique id for the machine pushing the updates in.