public void Clear_ExistingGuidPassed()
        {
            var cartID          = "9b3df90a-1007-4778-b614-91df990e0c95";
            var mockHttpContext = MockHttpSession.setSessionKey(cartID);

            _controller.ControllerContext.HttpContext = mockHttpContext.Object;
            // Act
            _controller.ClearCart();
            var okResult = _controller.Get();
            var items    = Assert.IsType <List <ShoppingCartItemDto> >(okResult.Result);

            // Assert
            Assert.Empty(items);
        }