testify vs declare

testify and declare both are verbs.

Word	Noun	Adjective	Verb	Adverb
testify	No	No	Yes	No
declare	No	No	Yes	No

As verbs, declare is a hypernym of testify; that is, declare is a word with a broader meaning than testify:

testify (verb)	declare (verb)
give testimony in a court of law	state emphatically and authoritatively
provide evidence for	state firmly
	make a declaration (of dutiable goods) to a customs official
	declare to be
	announce publicly or officially
	proclaim one's support, sympathy, or opinion for or against
	designate (a trump suit or no-trump) with the final bid of a hand
	authorize payments of