Some approvals fiddling

JsonApprovals.cs

public static class JsonApprovals
{
    public static void VerifyAsJson<T>(T item)
    {
        VerifyJson(item.ToJson()); //Using extension method ToJson from ServiceStack.Text
    }

    public static void VerifyJson(string json)
    {
        Approvals.Verify(new ApprovalTextWriter(json.Dump(), "txt")); //Using extension method Dump from ServiceStack.Text
    }
}

StupiedSample.cs

public class ShoppingCart
{
    public Dictionary<string, int> Contents = new Dictionary<string, int>();

    public void Put(string article, int qty)
    {
        if (Contents.ContainsKey(article))
            Contents[article] += qty;
        else
            Contents.Add(article, qty);
    }
}

public class Order
{
    public string OrderNo { get; set; }
    public DateTime Date { get; set; }
    public Dictionary<string, OrderLine> Lines { get; set; }

    public Order()
    {
        Lines = new Dictionary<string, OrderLine>();
    }
}

public class OrderLine
{
    public string ArticleNo { get; set; }
    public int Qty { get; set; }
    public int UnitPrice { get; set; }
}

public class OrderService
{
    public Order Initiate(ShoppingCart cart)
    {
        var order = new Order();
        order.Date = DateTime.Now;
        order.OrderNo = Guid.NewGuid().ToString();
        order.Lines = cart.Contents.Select(pair => new OrderLine { ArticleNo = pair.Key, Qty = pair.Value }).ToDictionary(pair => pair.ArticleNo, pair => pair);

        return order;
    }
}

Tests.cs

[TestFixture]
[UseReporter(typeof(DiffReporter))]
public class When_adding_bananas_and_milk_to_a_cart
{
    [Test]
    public void It_should_have_bananas_and_milk()
    {
        var cart = new ShoppingCart();
        cart.Put("Bananas", 2);
        cart.Put("Milk", 1);

        JsonApprovals.VerifyAsJson(cart.Contents);
    }
}

[TestFixture]
[UseReporter(typeof(DiffReporter))]
public class When_turning_a_cart_with_bananas_and_milk_to_an_order
{
    [Test]
    public void It_should_also_have_bananas_and_milk()
    {
        var cart = new ShoppingCart();
        cart.Put("Bananas", 2);
        cart.Put("Milk", 1);

        var order = new OrderService().Initiate(cart);

        JsonApprovals.VerifyAsJson(order.Lines);
    }
}