There are official test suits to go with CSS available from the W3C - here's the latest snapshot of the one for CSS2.1: http://www.w3.org/Style/CSS/Test/CSS2.1

There are official test suits to go with CSS available from the W3C - here's the latest snapshot of the one for CSS2.1: http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/ http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/ This version currently has 8777 tests, covers most areas of the spec but isn't complete.