public void GetSingleOrderCallsTheCorrectMethodFromTheUnderlyingCore() { //Arrange const int orderId = 999; _mockOrderQuery.Expect(x => x.GetSingleOrder(orderId)) .Return(new GetOrderResponseDTO()); //Act var response = _orderService.GetSingleOrder(orderId); //Assert Assert.IsInstanceOfType(typeof(GetOrderResponseDTO), response); _mockOrderQuery.VerifyAllExpectations(); }