A few days back Thomas Koch posted a timeline he worked up of the release of several popular PHP quality assurance tools:

Since I'm not a contributor to any QA tool I'll center around the user perspective and the process of establishing these tools in a small to middle web company like YMC. As an outline for the first part I thought to give an historical view on QA in PHP and therefor made a timeline of PHP QA milestones.

He includes both an image of the timeline and the dates as text for the releases of things like PHPUnit, eZ Components, Zend Framework, PHP_Depend and PHPUnderControl.