testimony vs testimonial

testimony and testimonial both are nouns.

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

As nouns, testimony and testimonial are synonyms defined as:

testimony (noun)	testimonial (noun)
a solemn statement made under oath	something that recommends (or expresses commendation of) a person or thing as worthy or desirable
an assertion offering firsthand authentication of a fact	something given or done as an expression of esteem
something that serves as evidence	something that serves as evidence

testimony (adjective)	testimonial (adjective)
	of or relating to or constituting testimony
	expressing admiration or appreciation