fyi: there is an archive with a bunch of tests (mostly mine but I occasionally add -adapted- samples from the list):

http://www.pragma-ade.nl/context/latest/cont-tst.7z

Quite some of these can be used for testing, some can also serve as examples of usage. I have a script that can process them and keep track of changes at a rough pixel level but simply have no time to keep up with that.