"/testfor" Coordinate Output Always True

Whenever I put in a command block "/testfor @p{x,y,z}" (x, y, and z being the coords) and I put a comparator next to it, the signal is always true. I have tested different parameters, and the other parameters work. It is just the x, the y, and the z coordinates that are broken. The Previous Output box gives the output: "{14:32:28} Unknown command. Try /help for a list of commands."

I am using the curly brackets instead of the regular brackets due to the bug tracker auto-fixing the brackets.