is my cas bad?

Ok so im pretty sure my cas is bad jus want confirmation before I buy one. So I'm not getting spark so I take out the cas set it upside-down plug it in turn the ignition on an with a sparkplug connected to the coil spin the cas. I get no spark, then when I take the plug off the cas and test the wires it is getting perfect voltage. So I ask the masses have I most likely found my problem?