test (as a noun, relating to a measure or an indicator of evaluation or judgment)

6. N-COUNT : usu sing, oft N of n

If an event or situation is a test of a person or thing, it reveals their qualities or effectiveness.

• It is a commonplace fact that holidays are a major test of any relationship.

... Cobuild

3. A basis for evaluation or judgment:

• "A test of democratic government is how Congress and the president work together" (Haynes Johnson).

... Am-Heritage, http://www.thefreedictionary.com/test