public void AddProduct_AddsAProductToTheList()
{
var item = fixture.Create <PurchaseItem>();
order = fixture.Create <PurchaseOrder>();
order.AddProduct(item);
Assert.Equal(item, order.GetList.Single());
}
public void AddProduct_WhenNulThrows()
{
order = fixture.Create <PurchaseOrder>();
Assert.Throws <ArgumentNullException>(() => order.AddProduct(null));
}