Software Testing Unit Testing

Software Testing Unit Testing#

Unit Testing#

  • Definition: Unit testing involves testing individual components or units of code in isolation. These units could be functions, methods, or classes.

  • Purpose: To verify that each unit works as expected and meets its specific requirements.

  • Benefits:

    • Early detection of defects

    • Improved code quality

    • Increased code maintainability

    • Supports regression testing

Integration Testing#

  • Definition: Integration testing combines multiple units or components to test their interactions and communication.

  • Purpose: To verify that different parts of the software work together as expected.

  • Benefits:

    • Identifies interface-related defects

    • Ensures data integrity and flow

    • Improves system stability

UnitTest#

Unittest is Python’s standard library for writing and running unit tests. It provides a structured approach to testing individual units of code (functions, methods, classes) to ensure they behave as expected.

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

Key Features:#

  • Test Cases: Define individual test scenarios using the TestCase class.

  • Test Suites: Organize test cases into collections for efficient execution.

  • Assertions: Verify expected outcomes using methods like assertEqual, assertTrue, etc.

  • Fixtures: Set up and tear down test environments using setUp() and tearDown() methods.

UnitTest Examples#

Basic Example: Testing a Simple Function#

Python

"""
Unit Testing is for the testing of functions
and methods
"""

import unittest

def add(x, y):
    return x + y

class TestAdd(unittest.TestCase):


    def test_add_positive_true(self):
        result = add(2, 3)
        self.assertEqual(result, 5)

    def test_add_positive_true_bad(self):
        result = add(2, 3)
        self.assertEqual(result, 100) 

    def test_add_negative(self):
        result = add(-1, 2)
        self.assertEqual(result, 1)
        
# ------ Examples of comparitive values
        
    def test_3_gt_2(self):
        self.assertGreater(3,2);

    def test_2_gt_3(self):
        self.assertGreater(2,3);
    
if __name__ == '__main__':
    # Setting the verbosity to 2
    # Gives details on what tests 
    # were ran and the outcomes
    unittest.main(verbosity=2)


"""
output:


test_2_gt_3 (__main__.TestAdd.test_2_gt_3) ... FAIL
test_3_gt_2 (__main__.TestAdd.test_3_gt_2) ... ok
test_add_negative (__main__.TestAdd.test_add_negative) ... ok
test_add_positive_true (__main__.TestAdd.test_add_positive_true) ... ok
test_add_positive_true_bad (__main__.TestAdd.test_add_positive_true_bad) ... FAIL    

======================================================================
FAIL: test_2_gt_3 (__main__.TestAdd.test_2_gt_3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "e:\My Drive\0_CSCI_127_JBD\Teaching_Modules\Module_Testing\unitTesting_example1.py", line 30, in test_2_gt_3
    self.assertGreater(2,3);
    ^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 2 not greater than 3

======================================================================
FAIL: test_add_positive_true_bad (__main__.TestAdd.test_add_positive_true_bad)       
----------------------------------------------------------------------
Traceback (most recent call last):
  File "e:\My Drive\0_CSCI_127_JBD\Teaching_Modules\Module_Testing\unitTesting_example1.py", line 20, in test_add_positive_true_bad
    self.assertEqual(result, 100)
AssertionError: 5 != 100

----------------------------------------------------------------------
Ran 5 tests in 0.004s

FAILED (failures=2)

"""

Testing a Class Method#

Python

"""
Unit Testing is for the testing of functions
and methods
"""

import unittest


class AddCaclulator:

    def __init__(self) -> None:
        pass

    def add(x, y):
        return x + y

class TestAdd(unittest.TestCase):

    def test_add_positive_true(self):
        result = myCalculator.add(2, 3)
        self.assertEqual(result, 5)

    def test_add_positive_true_bad(self):
        result = myCalculator.add(2, 3)
        self.assertEqual(result, 100) 

    def test_add_negative(self):
        result = myCalculator.add(-1, 2)
        self.assertEqual(result, 1)

    # ------ Examples of comparitive values
    def test_3_gt_2(self):
        self.assertGreater(3,2);

    def test_2_gt_3(self):
        self.assertGreater(2,3);

# global object
myCalculator = AddCaclulator

if __name__ == '__main__':
    # Setting the verbosity to 2
    # Gives details on what tests 
    # were ran and the outcomes
    unittest.main(verbosity=2)


'''
Output
# -------------------
test_2_gt_3 (__main__.TestAdd.test_2_gt_3) ... FAIL
test_3_gt_2 (__main__.TestAdd.test_3_gt_2) ... ok
test_add_negative (__main__.TestAdd.test_add_negative) ... ok    
test_add_positive_true (__main__.TestAdd.test_add_positive_true) 
... ok
test_add_positive_true_bad (__main__.TestAdd.test_add_positive_true_bad) ... FAIL

======================================================================
FAIL: test_2_gt_3 (__main__.TestAdd.test_2_gt_3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "e:\My Drive\0_CSCI_127_JBD\Teaching_Modules\Module_Testing\unitTesting_example2.py", line 36, in test_2_gt_3
    self.assertGreater(2,3);
    ^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 2 not greater than 3

======================================================================
FAIL: test_add_positive_true_bad (__main__.TestAdd.test_add_positive_true_bad)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "e:\My Drive\0_CSCI_127_JBD\Teaching_Modules\Module_Testing\unitTesting_example2.py", line 25, in test_add_positive_true_bad
    self.assertEqual(result, 100)
AssertionError: 5 != 100

----------------------------------------------------------------------
Ran 5 tests in 0.004s

FAILED (failures=2)

'''

Using Assertions#

Unittest provides several assertion methods to check different conditions:

Method

Checks that

assertEqual(a, b)

a == b

assertNotEqual(a, b)

a != b

assertTrue(x)

bool(x) is True

assertFalse(x)

bool(x) is False

assertIs(a, b)

a is b

assertIsNot(a, b)

a is not b

assertIsNone(x)

x is None

assertIsNotNone(x)

x is not None

assertIn(a, b)

a in b

assertNotIn(a, b)

a not in b

assertIsInstance(a, b)

isinstance(a, b)

assertNotIsInstance(a, b)

not isinstance(a, b)

There are also other methods used to perform more specific checks, such as:

assertAlmostEqual(a, b)

round(a-b, 7) == 0

assertNotAlmostEqual(a, b)

round(a-b, 7) != 0

assertGreater(a, b)

a > b

assertGreaterEqual(a, b)

a >= b

assertLess(a, b)

a < b

assertLessEqual(a, b)

a <= b

assertRegex(s, r)

r.search(s)

assertNotRegex(s, r)

not r.search(s)

assertCountEqual(a, b)

a and b have the same elements in the same number, regardless of their order.

Test Fixtures#

Unittest provides setUp() and tearDown() methods to set up and clean up resources before and after each test case:

Python

import unittest

class TestDatabase(unittest.TestCase):
    def setUp(self):
        # Connect to database

    def tearDown(self):
        # Close database connection

    def test_query(self):
        # Perform database query

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

Running Tests#

To run the tests, you can use the following command in your terminal:

Cmd

python test_file.py

For more detailed output, use the -v flag:

Cmd

python -m unittest -v test_file.py

Remember:

  • Each test case should be independent.

  • Test cases should cover different scenarios and edge cases.

  • Use clear and descriptive test case names.

  • Strive for high test coverage.

Contents