Wiktionary
smell test
n. 1 (context idiomatic English) An informal method for determining whether something is authentic, credible, or ethical, by using one's common sense or sense of propriety. 2 An inspection of an object using the sense of smell, as for freshness of food. 3 (context physiology English) An assessment of a subject's ability to detect and distinguish odors.
Usage examples of "smell test".
If I did a smell test I could find a hospital with my eyes closed: disinfectant, medicine, bad cafeteria food, and recycled air through old vents, stale and artificial.
A little smell test is all that was needed to disgust me with school for all time.