acid test

Finally, a word about the acid test in all of this.

They say the program has failed the acid test of science.

"The acid test for us will be how well our students are doing in the classroom."

"The acid test is to talk to consumers and find out what they think."

In brief, a real acid test is yet to come.

This will be the acid test of an effective European common foreign and security policy.

An acid test, considering what last happened between us two.

Well, does that represent some kind of acid test to the Church?

The acid test is whether Presidents gave more than they got.

Today this is the acid test for the present and future construction of Europe.