IQ test vs mental testing

IQ test and mental testing both are nouns.

Word	Noun	Adjective	Verb	Adverb
IQ test	Yes	No	No	No
mental testing	Yes	No	No	No

As nouns, mental testing is a hypernym of IQ test; that is, mental testing is a word with a broader meaning than IQ test:

IQ test: a psychometric test of intelligence
mental testing: any standardized procedure for measuring sensitivity or memory or intelligence or aptitude or personality etc

Other hypernyms of IQ test include mental test, psychometric test, test.

IQ test (noun)	mental testing (noun)
a psychometric test of intelligence	any standardized procedure for measuring sensitivity or memory or intelligence or aptitude or personality etc