public void SetUp()
{
_dir = new Mock <Director>();
_dir.CallBase = true;
_director = _dir.Object;
_vice = new Mock <VicePresident>();
_vice.CallBase = true;
_vicepresident = _vice.Object;
_presi = new Mock <President>();
_presi.CallBase = true;
_president = _presi.Object;
_director.SetSuccessor(_vicepresident);
_vicepresident.SetSuccessor(_president);
}