import unittest from django.core.exceptions import ValidationError class TestValidationError(unittest.TestCase): def test_messages_concatenates_error_dict_values(self): message_dict = {} exception = ValidationError(message_dict) self.assertEqual(sorted(exception.messages), []) message_dict['field1'] = ['E1', 'E2'] exception = ValidationError(message_dict) self.assertEqual(sorted(exception.messages), ['E1', 'E2']) message_dict['field2'] = ['E3', 'E4'] exception = ValidationError(message_dict) self.assertEqual(sorted(exception.messages), ['E1', 'E2', 'E3', 'E4'])