a litmus test

something that shows clearly what someone's opinions or intentions are

Usage notes: Litmus is a substance used in chemical tests because it changes colour.

His views on abortion are effectively a litmus test of his views on women's rights.

Name	Pronounced	Usage
Sachairi	-	Scottish
Danica	-	Serbian, Croatian, Slovene, Slovak, Czech, Macedonian, English
Olayinka	-	Western African, Yoruba
Lyla	LIE-lə	English
GÖKhan	-	Turkish
Paolo	POW-lo	Italian