def test_invoice_arithmetics(self):
item = Item('line item', 12, 2, 19)
assert item.get_price() == 12.00
assert item.get_total_price_net() == 24.00
assert item.get_total_price() == 28.56
def test_item_with_no_tax(self):
item = Item('line item', 12, 2, 0)
assert item.get_total_price_net() == 24.00
assert item.get_total_price() == 24.00