Giving testimony is a legal process in which a witness provides evidence in a court of law. Attesting, deposing, swearing, and avowing are all forms of giving testimony. Attesting is the act of signing or affirming a document as a witness. Deposing is the act of testifying under oath in a legal proceeding. Swearing is the act of making a solemn promise or affirmation to tell the truth. Avowing is the act of declaring something to be true.