These are no substitute for xts, rendercheck and cairo-test-suite. They
are intended to exercise corner cases in the batch management of long
drawing commands and more explicit checking of the acceleration paths.

Useful tools:

# Packed YUV Xv tester
gst-launch-1.0 videotestsrc pattern=snow ! 'video/x-raw,format=UYVY,width=640,height=360' ! xvimagesink

# Planar YUV Xv tester
gst-launch-1.0 videotestsrc pattern=snow ! 'video/x-raw,format=I420,width=640,height=360' ! xvimagesink
