public void CanInsertSalesIntoDatabase()
        {
            Mock <IDatabaseService>  mockDatabaseService = new Mock <IDatabaseService>();
            Mock <IDateService>      mockDateService     = new Mock <IDateService>();
            Mock <IInventoryService> mockInvServ         = new Mock <IInventoryService>();
            Mock <ISaleFactory>      mockSaleFactory     = new Mock <ISaleFactory>();

            CreateSaleCommand createSaleCommand =
                new CreateSaleCommand(
                    mockDatabaseService.Object,
                    mockDateService.Object,
                    mockInvServ.Object,
                    mockSaleFactory.Object
                    );

            createSaleCommand.Execute(new CreateSaleModel()
            {
                CustomerId = 1,
                EmployeeId = 1,
                ProductId  = 1,
                Quantity   = 3
            });
        }