Whenever use the "/testforblock" command in a command block, it won't let me test for a pressed button.  Whenever I try to, it comes up with the message "The block at X,Y,Z did not match the expected state".

Steps: In a repeating command block, I typed in the command, "/testforblock (Position of stone button) stone_button ["button_pressed_bit"=true]".  Then I set the repeating command block to "always active" to constantly test for a pressed button at the specified location. 

Observed results: When I press the button at the location the command block specifies to test if it works, it doesn't.  So I check the output to see why it doesn't work and it says "The block at X,Y,Z did not match the expected state".

Expected Results: The command block testing for a pressed button at the specified location should work and activate any redstone/command block contraption attached when the button is pressed.