litmus test

There are no political, religious or secularist orthodoxies or litmus tests.

Some also see cryptocurrency as increasingly a litmus test for where stocks will go.

The proposals would be a “litmus test for the fight against red tape in Brussels and Strasbourg,” German Chancellor Friedrich Merz told a joint summit on digital sovereignty with French President Emmanuel Macron.

And the popular tech YouTuber Marques Brownlee said it was a "litmus test" for fans who "buy or defend anything Apple releases".

The all-volunteer organization sends applicants a lengthy questionnaire with dozens of litmus test questions: Do they support diverting funds away from law enforcement?