Added extra null tests and TODO's to complete

TODO: add a test for setting the item description
TODO: add a test for setting the item code
TODO: add a test for setting the buyer name
TODO: add a test for setting the buyer address1
TODO: add a test for setting the buyer address2
TODO: add a test for setting the buyer city
TODO: add a test for setting the buyer state
TODO: add a test for setting the buyer zip
TODO: add a test for setting the buyer country
TODO: add a test for setting the buyer email
TODO: add a test for setting the buyer phone