public async Task GetStockItem_Returns_OkObjectResult()
        {
            //Arrange
            var id = 2;

            _fixture.MockStockItemRepository.Setup(x => x.GetStockItemAsync(It.IsAny <long>()))
            .ReturnsAsync(_fixture.StockItems.Single(d => d.Id == id));

            var controller = new StockItemController(_fixture.MockStockItemRepository.Object);

            //Act
            var result = await controller.GetStockItem(id);

            //Assert
            var okResult  = result.Should().BeOfType <OkObjectResult>().Subject;
            var stockItem = okResult.Value.Should().BeAssignableTo <GetStockItemDto>().Subject;

            okResult.StatusCode.Should().Be(200);
            stockItem.Id.Should().Be(id);
            stockItem.StockType.Should().Be("Beverage");
            stockItem.UnitOfMeasureCode.Should().Be("ml");
            stockItem.Name.Should().Be("Coca-Cola");
        }