unittest.py

import unittest


def square_items(list_of_number):
    return [item ** 2 for item in list_of_number]


class TestUnitTest(unittest.TestCase):
    def test_square_items(self):
        self.assertEqual(square_items([1, 2, 3, 4]), [1, 4, 9, 16])


if __name__ == "__main__":
    unittest.main()