Did Clemenza really pass the loyalty test? though or
Perhaps Clemenza was just lucky! by sitting tight and doing nothing because he was not losing his territories, got away with it?
ie: Clemenza's loyalty was not tested?
Choosing to do nothing is an active, conscious decision. Michael asked both to be patient. Clem was patient, so he did what Michael told him to do. That showed loyalty.
I also saw in that scene a hint, perhaps, of things to come. Vito finally intervenes and says to Clem and Tess: "Do you trust my judgment?" "Always, Godfather," Clem replies, fervently. Tess hisses, "Yessss...." And, if I'm not mistaken, as they leave, Tess gives Michael a left-handed handshake--a sure sign of perfidy to come.
