def test_write_bills(self):
bills = read_bills()
write_bills(bills)
bills = read_bills()
self.assertEqual(20, len(bills))
self.assertEqual('Electric Ireland', bills[0][0])
self.assertEqual('credit', bills[19][6])
def test_read_bills(self):
bills = read_bills()
self.assertEqual(49, len(bills))
self.assertEqual('Electric Ireland', bills[1][0])
self.assertEqual('credit', bills[20][6])
self.assertEqual('credit', bills[23][6])