unit test in Python

import unittest
import main

class TestMain(unittest.TestCase):
    def setUp(self):
        print("About to test a function")

    def test_sum(self):
        test_param = 10
        result = main.sum(test_param)
        self.assertEqual(result, 15)

    def test_sum2(self):
        test_param = "abc"
        result = main.sum(test_param)
        self.assertIsInstance(result, ValueError)

    def test_sum3(self):
        test_param = None
        result = main.sum(test_param)
        self.assertIsInstance(result, TypeError)

     def tearDown(self):
        print("cleaning up")


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


# testing in main.py
# def sum(num):
    #try:
     #return int(num) + 5

    #except (ValueError, TypeError) as error:
        #return error