Litmus test

Exams, not interviews, have become the litmus test for entry to university.

Temple, under its new coach, Ray Morrison, formerly of Vanderbilt, will be put to the blue litmus test Friday night when it takes on Georgetown.

For good reasons or bad, early membership of the currency union has become the litmus test of being a "good European."

He opposes a constitutional amendment to ban same-sex marriage—a litmus test for many social conservatives

For years, quoting lines from “Manhattan” or another film by Mr. Allen on a date could be a romantic litmus test, a way to find out if a potential partner also loved E. E. Cummings, Paris, 1930s jazz and the sophisticated, cultured world the films often came to represent.

"[…] I don't know National Rail numbers, but I do know that after the pandemic I used to go round a lot of the London stations, and they had far more locations shut than I did at St Pancras. That was very much my litmus test."