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Python unittest – assertIsNotNone() function

  • Last Updated : 29 Aug, 2020

assertIsNotNone() in Python is a unittest library function that is used in unit testing to check that input value is not None. This function will take two parameters as input and return a boolean value depending upon assert condition. If input value is not equal to None assertIsNotNone() will return true else return false.

Syntax: assertIsNotNone(testValue, message)

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Parameters: assertIsNotNone() accept two parameters which are listed below with explanation:



  • testValue:  test variable as the input value to check equality with None
  • message: a string sentence as a message which got displayed when the test case got failed.

Listed below are two different examples illustrating the positive and negative test case for given assert function:

Example 1: Negative Test case

Python3




# unit test case
import unittest
  
class TestMethods(unittest.TestCase):
    # test function 
    def test_negative(self):
        firstValue = None
        # error message in case if test case got failed
        message = "Test value is none."
        # assertIsNotNone() to check that if input value is not none
        self.assertIsNotNone(firstValue, message)
  
if __name__ == '__main__':
    unittest.main()

Output:

F
======================================================================
FAIL: test_negative (__main__.TestMethods)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "p1.py", line 11, in test_negative
    self.assertIsNotNone(firstValue, message)
AssertionError: unexpectedly None : Test value is none.

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)


Example 2: Positive Test case

Python3




# unit test case
import unittest
  
class TestMethods(unittest.TestCase):
    # test function 
    def test_positive(self):
        firstValue = "geeks"
        # error message in case if test case got failed
        message = "Test value is  none."
        # assertIsNotNone() to check that if input value is not none
        self.assertIsNotNone(firstValue, message)
  
if __name__ == '__main__':
    unittest.main()

Output:

.
----------------------------------------------------------------------
Ran 1 test in 0.000s

OK

Reference: https://docs.python.org/3/library/unittest.html




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