test period vs trial period

test period and trial period both are nouns.

Word	Noun	Adjective	Verb	Adverb
test period	Yes	No	No	No
trial period	Yes	No	No	No

As nouns, test period and trial period are synonyms defined as:

test period and trial period: a period of time during which someone or something is tested

test period (noun)	trial period (noun)
a period of time during which someone or something is tested	a period of time during which someone or something is tested