I have tried to implement it in gem2deb-testrunner (smoke-test branch of gem2deb)
http://anonscm.debian.org/cgit/pkg-ruby-extras/gem2deb.git/commit/?h=smoke-test&id=c4ccfad2fc3962b2cecea96a51206e469d6a8853 Can someone review it? May be using sprockets directly is better, but I could not get that to work. I thought a heavier test is better than no test.
