public void Assign()
{
AbstractTerm term = new AbstractTerm();
ConstantTerm con = new ConstantTerm("ali");
term.Assign(con);
Assert.AreSame(term.Dereference(), con);
Assert.AreSame(term.Dereference(), con.Dereference());
Assert.AreEqual(term.Data(), con.Data());
Assert.AreSame(term.Reference(), con.Reference());
Assert.IsFalse(term.IsList);
Assert.IsFalse(term.IsObject);
Assert.IsFalse(term.IsReference);
Assert.IsFalse(term.IsStructure);
Assert.IsTrue(term.IsConstant);
}