Testfor command not working with radius

Solution 1:

Had just the same problem but did some testing on it! it seems that the old stupid north south east west bug still apply to this! I simply switched sides that I had my comparator hooked up to and it worked!

Solution 2:

First, you need 2 hoppers facing each other. Place any item in the hopper. The item should be going back and forth between the hoppers. Now grab a redstone comparator. Stand on top of any hopper and place the comparator outwards. The two redstone torches on the comparator should blink while the bottom one should not light up. Now grab a command block. Type in: testfor @p[r=6] Now place another comparator while standing on top of the command block facing a block with a redstone torch on one side. The redstone torch should turn off. Now run redstone wire to yet another redstone torch on another block. Connect the torch to an iron door. Then the door will open when a player gets close!