With the advent of AF, facilities such as microprisms and split images that used to be standard in viewfinders for determining optimal focus have been eliminated. Unfortuately, success in your test would only mean that the AF was no worse than trying to focus manually using a viewfinder and focusing screen not engineered with that in mind. Then try to see if you can manually focus it any sharper than the AF system does.
Just put the camera on a tripod and take a picture of an iso chart straight in front of the camera ( NOT AT AN ANGLE! ) using AF.
