def test_right_value(self):
for key, value in MAPPING.items():
self.assertEqual(digit2word(key), value)
self.assertEqual(digit2word_2nd(key), value)
self.assertEqual(digit2word_3rd(key), value)
def test_wrong_value(self):
"""Return 'unknown' in case of wrong value"""
self.assertEqual(digit2word('pippo'), 'unknown')
self.assertEqual(digit2word_2nd(5), 'unknown')
self.assertEqual(digit2word_3rd(5), 'unknown')