A sniff test is deciding whether food has gone off by smelling it. Give it the sniff test, failed the sniff test, the usual sniff test.
It catches spoilage and misses the bacteria that actually poison people, since salmonella has no smell at all. The figurative use is common, and something that fails the sniff test is suspicious rather than merely wrong.
1nounsniff testDeciding whether food has gone off by smelling it.
“The milk was a day past its date, so I gave it the sniff test before pouring.”
sniff test is a test.
Sniff plus test, with sniff an imitative word for drawing air sharply through the nose.
From sniff + test.
Etymology from Wiktionary, CC BY-SA
Practised in Smell & Taste