public void GetOrderTotalPrice_LoggerShouldBeCalled()
        {
            // arrange
            articleCatalogService.RegisterArticle(butterArticle);
            articleCatalogService.RegisterArticle(milkArticle);
            articleCatalogService.RegisterArticle(breadArticle);
            // orderService
            var loggerMock      = new Mock <ILogger <OrderService> >();
            var moqOrderService = new OrderService(loggerMock.Object, articleCatalogService, orderRepository);
            var orderId         = orderService.CreateNewOrder();

            moqOrderService.RegisterDiscount(orderId, new MilkDiscountService(articleCatalogService));
            moqOrderService.RegisterDiscount(orderId, new BreadDiscountService(articleCatalogService));
            moqOrderService.AddArticleToOrder(orderId, milkArticle.Id, 8);
            moqOrderService.AddArticleToOrder(orderId, butterArticle.Id, 2);
            moqOrderService.AddArticleToOrder(orderId, breadArticle.Id, 1);
            // act
            var price = moqOrderService.GetOrderTotalPrice(orderId);

            // assert
            loggerMock.Verify(
                x => x.Log(
                    LogLevel.Information,
                    It.IsAny <EventId>(),
                    It.IsAny <It.IsAnyType>(),
                    It.IsAny <Exception>(),
                    (Func <It.IsAnyType, Exception, string>)It.IsAny <object>()),
                Times.Once);
        }