You can't use /testforblock x y -0 wooden_button, it says then that its searching for a block at x y 0
MC-42494
You cant detect a block thats is at x y -0
Resolved
Invalid
0
Correct, because testfor adds +0.5 which would be -0+0.5=0.5 which rounds to 0.
A little math will fix your problem.