unit test 2 in Python

import unittest
import main

class TestMain(unittest.TestCase):
    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.assertEqual(result, "Please, enter a number!")

    def test_sum3(self):
        test_param = None
        result = main.sum(test_param)
        self.assertEqual(result, "Please, enter a number!")

    def test_sum4(self):
        test_param = ''
        result = main.sum(test_param)
        self.assertEqual(result, "Please, enter a number!")


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

# testing in main.py
# def sum(num):
   # try:
      # return int(num) + 5
   # except (ValueError, TypeError) as error:
      #  return ("Please, enter a number!")