This is a bug I found in both Minecraft 1.8.9 and 15w51a (originally, still happens in 16w02a), in which hoppers don't respond to redstone changes. In the imgur album, Pictures 1+2 are using a similar setup: power torch, manually update the hopper, remove power source, take screenshot using Print Screen, save it in Paint (since that's what I have on hand), move on to the next picture. For Picture 3, I just directly powered the hopper and it didn't work.

http://imgur.com/gallery/xxgXf/