sniff test

Etymology 1
By metaphorical extension from an actual test one might perform with one's sense of smell, as for freshness of food or cleanness of clothes.

Noun

 * 1)  An informal check of an idea or proposal, using one's common sense or sense of propriety.

Noun

 * 1) A fluoroscopic medical test during which the examinee is asked to "sniff" (quickly breathe in through the nose); diaphragm fluoroscopy.