I loaded up the new snapshot, very excited, spawned some llamas in, browsed a woodland mansion, then decided to go ride a llama. I saddled a llama I spawned in (with carpets), gave it a chest, then got on. I found that I could not control the llama using my movement keys (I use up arrow, down arrow, left arrow & right arrow). I tried to use a carrot on a stick, then changed my controls to wasd, but I still couldn't move it.

How to do this:
Spawn a llama
Saddle it
Ride It
Then you can't control it