public void Unify_list_ref_lis()
{
ListTerm list1 = new ListTerm();
list1.Next = new AbstractTerm();
list1.Next.Next = new ConstantTerm("[]");
ListTerm list2 = new ListTerm();
list2.Next = new ConstantTerm("ali");
list2.Next.Next = new ConstantTerm("[]");
Assert.IsTrue(list1.Unify(list2));
Assert.AreEqual(list1.Head.Data(), list2.Head.Data());
}