In American English when something "doesn't pass the sniff test" it means that it is quite obviously bullshit. As in, something that might look nice but obvious

In American English when something "doesn't pass the sniff test" it means that it is quite obviously bullshit. As in, something that might look nice but obviously smells of shit. Less crudely, you might describe milk that way: spoiled milk looks like good milk but it definitely does not smell like good milk. It doesn't really have anything to do with a person in particular, unless historic usage was different from modern usage. I don't know about other languages, but I don't think there's any connection in English.