acid tests

/AE1 S AH0 D T EH0 S T S/
noun
  1. 1

    A rigorous test or appraisal of the quality or worth of something.

  2. 2

    In the 1960s, a party based around the use and advocacy of the psychedelic drug LSD ("acid").

Source: https://en.wiktionary.org/wiki/acid%20test, https://en.wiktionary.org/wiki/acid%20tests