The Collaborative International Dictionary of English v.0.48:

Testate \Tes"tate\, a. [L. testatus, p. p. of testari. See
   Testament.] (Law)
   Having made and left a will; as, a person is said to die
   testate. --Ayliffe.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Testate \Tes"tate\, n. (Law)
   One who leaves a valid will at death; a testate person. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

testate
    adj 1: having made a legally valid will before death [ant:
           intestate]
    n 1: a person who makes a will [syn: testator, testate]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

TESTATE. One who dies having made a testament; a testator. This word is used
in this sense, in the act of the legislature of Pennsylvania, entitled "An
act relative to dower and for other purposes." Sect. 2, 5 Sm. Laws, 257.