public void DeleteTest() { Mock <IDataFiller> mockRepository = new Mock <IDataFiller>(); mockRepository.Setup(x => x.Fill()).Returns(data); Repository repository = new Repository(mockRepository.Object); List <Burger> Burgers = (List <Burger>)repository.GetAllBurgers(); List <Customer> customers = (List <Customer>)repository.GetAllCustomers(); List <Employee> employees = (List <Employee>)repository.GetAllEmployees(); List <Order> orders = (List <Order>)repository.GetAllOrders(); Burger Burger = Burgers[0]; Customer customer = customers[0]; Employee employee = employees[1]; Order order1 = new Order(customer, Burgers, employee, 10); Order order2 = new Order(customer, Burgers, employee, 20); repository.AddOrder(order1); repository.AddOrder(order2); Burgers.Count.Should().Be(3); customers.Count.Should().Be(4); employees.Count.Should().Be(3); orders.Count.Should().Be(2); repository.DeleteCustomer(customer); repository.DeleteBurger(Burger); repository.DeleteOrderHead(); repository.DeleteOrder(0); repository.DeleteEmployee(employee); Burgers.Count.Should().Be(2); customers.Count.Should().Be(3); employees.Count.Should().Be(2); orders.Count.Should().Be(0); }