I'm trying to do functional tests on some PHP code which generates iCal output. Is there a smallish library (PHP) or standalone program (any non-heavyweight implementation that is easily runnable on CentOS 5.x) that can do a basic validation of iCal data, a la http://icalvalid.cloudapp.net/ ??
The code that site is based on is .NET dependent, which won't work on our platform.