ShippingAddressPage.Asserter.cs

public partial class ShippingAddressPage
{
    public void AssertPurchaseOrders(List<PurchaseOrder> purchaseOrders)
    {
        for (int i = 0; i < purchaseOrders.Count; i++)
        {
            Assert.AreEqual(GetFormattedPurchaseOrder(purchaseOrders[i]), PurchaseOrderRows[i].Text);
        }
    }

    private string GetFormattedPurchaseOrder(PurchaseOrder purchaseOrder)
    {
        return $"Your product: {purchaseOrder.ProductName} costs {purchaseOrder.Price}";
    }
}