Holy mother of complexity! They don't make autopkgtest easy to understand, do they? And no virtual driver for pbuilder/cowdancer, just to put an extra nail in my wrist (if I may use a seasonal metaphor.)
Anyway, I believe the upload I've just pushed has correct autopkgtest support, explicitly testing the installed binary /usr/bin/fossil. If this passes muster, please unblock! And if not, I'd very much appreciate hints as to how I could improve it. Cheers, --Barak.