public void Unify_after_assignment()
        {
            AbstractTerm term = new AbstractTerm();
            ConstantTerm con  = new ConstantTerm("test");

            term.Assign(con);

            Assert.AreEqual(term.Unify(con), con.Unify(term));
        }
        public void Unify_con_ref()
        {
            AbstractTerm term = new AbstractTerm();

            ConstantTerm con = new ConstantTerm("ali");

            Assert.IsTrue(con.Unify(term));

            Assert.AreSame(term.Data(), con.Data());
        }