
PASS Must have a .shippingOption IDL attribute. 
PASS .shippingOption attribute must default to null. 
PASS If there is a single shipping option, but selected is false, then .shippingOption must be null. 
PASS If there are multiple shipping options all with `selected` set to false, then .shippingOption is null. 
PASS Given multiple shipping options, it must use the selected shipping option for .shippingOption value. 
PASS If there are multiple of the shipping options with selected true, then .shippingOption is the last selected shipping option in order.