public RoomReservation(
     IHotel hotel,
     IFindRoom findFreeRoom)
 {
     _hotel        = hotel;
     _findFreeRoom = findFreeRoom;
 }
 public RoomReservavtionTests()
 {
     _hotel           = Substitute.For <IHotel>();
     _hotel.Rooms     = HotelRooms();
     _findFreeRoom    = Substitute.For <IFindRoom>();
     _roomReservation = new RoomReservation(_hotel, _findFreeRoom);
 }