def test_get_present_item(self):
item_list = IdList()
item1 = Item('id1')
item2 = Item('id2')
item_list.add(item1)
item_list.add(item2)
assert item_list.get('id1') is item1
assert item_list.get('id2') is item2
def test_get_not_present_item(self):
item_list = IdList()
assert item_list.get('id') is None