Quote Originally Posted by iMUSTbeTHEdevil
I really wonder if Itachi was gauging his own strength against his own clan, or really trying to figure out how he would do against another opponent, and this was the way to find out
Isn't that the same thing. If he wanted to gauge his own strength and see how he would fare against another Uchiha in battle then its pretty much the same isn't it. He probably killed his clan to test his own capacity as he said and there would be no need for him to test himself against the clan unless he knew that there was someone more powerful out there which is why he needed to know just how strong he was.