testament vs testimony

testament and testimony both are nouns.

Word	Noun	Adjective	Verb	Adverb
testament	Yes	No	No	No
testimony	Yes	No	No	No

As nouns, testimony is a hypernym of testament; that is, testimony is a word with a broader meaning than testament:

Other hypernyms of testament include testimonial.

testament (noun)	testimony (noun)
a profession of belief	a solemn statement made under oath
a legal document declaring a person's wishes regarding the disposal of their property when they die	an assertion offering firsthand authentication of a fact
strong evidence for something	something that serves as evidence