public void TestDecreaseAmountOnProductLine()
{
// Arrange
var context = new Mock <ControllerContext>();
var session = new MockHttpSession();
List <ProductLine> productLineList = new List <ProductLine>();
ShoppingCartController cartController = new ShoppingCartController();
cartController.ControllerContext = context.Object;
Product product = new Product();
product.ProductId = 1;
product.Price = 100;
ProductLine productLine = new ProductLine();
productLine.Amount = 1;
productLine.Product = product;
productLineList.Add(productLine);
session.insertIntoDictionary("shoppingCart", productLineList);
context.Setup(m => m.HttpContext.Session).Returns(session);
// Act
cartController.Add(product);
cartController.DecreaseAmount(productLine.Product.ProductId);
// Assert
Assert.AreEqual(1, productLine.Amount);
}