Both Uses

testament
in
As You Like It
(Auto-generated)

...therefore, allow me such exercises as may become a gentleman, or give me the poor allottery my father left me by testament; with that I will go buy my fortunes.
Scene 1.1 *

testament = written instructions expressing how somebody wants their property distributed after they die
First, for his weeping into the needless stream; 'Poor deer,' quoth he 'thou mak'st a testament As worldlings do, giving thy sum of more To that which had too much:' then, being there alone, Left and abandoned of his velvet friends; "Tis right'; quoth he; 'thus misery doth part The flux of company:' anon, a careless herd, Full of the pasture, jumps along by him And never stays to greet him; 'Ay,' quoth Jaques, 'Sweep on, you fat and greasy citizens; 'Tis just the fashion; wherefore do you look Upon that poor and broken bankrupt there?'†
Scene 2.1

testament = strong proof of something, or a formal written statement

Definitions:

(1) (testament)
evidence or proof of something, or a formal written statement — such as a will or one of the two main parts of the Christian Bible

Most commonly, you can substitute "evidence" or "proof" for testament. But see the first exemplary sample sentences for other common word substitutions.
(2) (meaning too rare to warrant focus)