Resizing an array within a class

I have an issue that's been bothering me.

I have an assignment to do which involves creating a program that does several tasks, using OOP.

The assignment is creating a shopping cart using separate classes and one of the tasks is to eliminate one item from the class.

I have it set it up like this.

Product class is:

class Product
{
    private string name;
    private decimal price;

    public Product(string name, decimal price)
    {
        this.name = name;
        this.price = price;
    }

Shopping cart class is:

class ShoppingCart
{
    private Product[] products;

    public ShoppingCart(Product[] products)
    {
        this.products = products;
    }

To remove the last item, I'm trying this within the ShoppingCart class.

public void RemoveLastProductFromCart()
{
   Array.Resize(ref products, products.Length - 1);
}

But it's not resizing the Product[] products and I cannot find another way to do so. I have to use arrays because we haven't gotten to lists yet.

EDIT: This is the test I have to check if the resizing works, and the function is called:

        [TestMethod]
    public void ShouldRemoveLastProductInCart()
    {
        Product[] products =
        {
          new Product("Milk", 12.10m),
          new Product("Meat", 14.15m)
        };

        ShoppingCart cart = new ShoppingCart(products);
        cart.RemoveLastProductFromCart();
        Assert.AreEqual(1, products.Length);
    }