Sirius takes his makeshift exam, crafted for him specifically because no one else’s resume consists only of 7 NEWTS (with four Os), unfinished Auror training, and guerrilla warfare and field healing. It also has a five year gap due to wrongful imprisonment, which Sirius knows can only have happened a handful of times in the history of Azkaban. It probably helps, too, that Sirius is related to Phineas Nigellus Black, and that Sirius himself is the only Black of his generation, now that Regulus is gone and his cousins all married. But Sirius doesn’t care