Lewis & Short

testātor, ōris, m. [testor].

  1. I. One who bears witness or testifies to a thing, a witness (very rare), Prud. Cath. 12, 85.
  2. II. One who makes a will or testament, a testator (the predom. jurid. signif. of the word, but not in Cic.), Dig. 28, 3, 17; 31, 1, 89; Suet. Ner. 17; Lact. 4, 20 al.