import unittest from pixelated.register import validate_username class TestRegister(unittest.TestCase): def test_username_raises_error_when_it_contains_uppercase_letters(self): with self.assertRaises(ValueError): validate_username('INVALIDUSERNAME') def test_username_raises_error_when_it_contains_special_characters(self): with self.assertRaises(ValueError): validate_username('invalid@username') def test_username_pass_when_valid(self): try: validate_username('a.valid_username-123') except: self.fail('Valid username should not raise an exception')