I wonder if this kind of "advice" has always been prevalent, or if it's an artifact of the Internet that everyone thinks they're smarter than everyone else and feels like coming up with "tests" like this. In a real friendship you'll have months or years of context on how a person acts that you'll use to actually have a decent picture of their personality, their strengths and weaknesses, any reactionary tendencies, etc and you won't need to "test" if they're a real ally because you'll have an idea of what's going on.