at·test 
(ə-tĕst)
(ə-tĕst)v. at·test·ed, at·test·ing, at·tests
v.tr.
1. To affirm to be correct, true, or genuine: The date of the painting was attested by the appraiser.
2.
a. To certify by signature or oath: attest a will.
b. To certify in an official capacity.
3.
a. To supply or be evidence of: Her fine work attests her ability. See Synonyms at indicate.
b. Linguistics To confirm the existence, usage, or currency of (a word, for example), as by being recorded in writing.
4. To put under oath.
v.intr.
To bear witness; give testimony: attested to their good faith.
n.
Archaic Attestation.
[Latin attestārī : ad-, ad- + testārī, to be witness (from testis, witness; see trei- in the Appendix of Indo-European roots).]
at·testant n.
at′tes·tation (ăt′ĕs-tāshən, ăt′ə-stā-) n.
at·tester, at·testor n.