I wouldn’t call someone a friend until we’ve hung out [for purely social purposes; not school projects] a few times. Typically though, if that person in question had a previous “role” in my life before becoming a friend, I would call them by that role instead of friend. Example being, my housemates. They’re awesome guys, fun to hang out with, but I won’t refer to them as friends, only housemates, because I lived with them before we had any kind of bond.