Rework unittest content and tests. Add mock testing to the demo

Author: IshaanDesai

05_testing_and_ci/examples/python_testing/test_operations_unittests.py

@@ -1,9 +1,10 @@
 """
 Tests for mathematical operations functions.
 """
-from operations import find_max, find_mean
+from operations import MathOperations
 import unittest
 from unittest import TestCase
+from unittest.mock import MagicMock
 import csv
 
 
@@ -13,8 +14,8 @@ class TestOperations(TestCase):
     """
     def setUp(self):
         # Fixture
-        self.data1 = [43, 32, 167, 18, 1, 209]
-        self.data2 = [3, 13, 33, 23, 498]
+        self._data = [43, 32, 167, 18, 1, 209, 17]
+        self._math_ops = MathOperations(self._data)
 
     # Unit test
     def test_find_max(self):
@@ -25,7 +26,7 @@ def test_find_max(self):
         expected_max = 209
 
         # Actual result
-        actual_max = find_max(self.data1)
+        actual_max = self._math_ops.find_max()
 
         # Test
         self.assertEqual(actual_max, expected_max)
@@ -36,49 +37,62 @@ def test_find_mean(self):
         Test operations.find_mean
         """
         # Expected result
-        expected_mean = 78.33
+        expected_mean = 69.57
 
         # Actual result
-        actual_mean = find_mean(self.data1)
+        actual_mean = self._math_ops.find_mean()
 
         # Test
         self.assertAlmostEqual(actual_mean, expected_mean, 2)
 
-    # Integration test
-    def test_mean_of_max(self):
+    # Unit test
+    def test_unit_find_median(self):
         """
-        Test operations.find_max and operations.find_mean
+        Test operations.find_median
         """
         # Expected result
-        expected_mean_of_max = 353.5
+        expected_median = 32
 
-        maximum1 = find_max(self.data1)
-        maximum2 = find_max(self.data2)
+        # Mock reorder_data to isolate the test
+        self._math_ops.reorder_data = MagicMock(return_value=[1, 17, 18, 32, 43, 167, 209])
 
         # Actual result
-        actual_mean_of_max = find_mean([maximum1, maximum2])
-        
+        actual_median = self._math_ops.find_median()
+
+        # Test
+        self.assertEqual(actual_median, expected_median)
+
+    # Integration test
+    def test_median(self):
+        """
+        Test operations.find_median
+        """
+        # Expected result
+        expected_median = 32
+
+        # Actual result
+        actual_median = self._math_ops.find_median()
+
         # Test
-        self.assertEqual(actual_mean_of_max, expected_mean_of_max)
+        self.assertEqual(actual_median, expected_median)
 
     # Regression test
-    def test_regression_mean(self):
+    def test_reg_reorder_data(self):
         """
-        Test operations.find_mean on a previously generated dataset
+        Test operations.reorder_data with data from CSV file
         """
-        with open("mean_data.csv") as f:
+        with open("reordered_data.csv") as f:
             rows = csv.reader(f, quoting=csv.QUOTE_NONNUMERIC)
-            # Fixture
-            data = next(rows)
-            
-            # Expected result
-            reference_mean = next(rows)
+        
+            for row in rows:
+                expected_reordered_data = row
 
         # Actual result
-        actual_mean = find_mean(data)
+        self._math_ops.reorder_data()
+        actual_reordered_data = self._math_ops._data
 
         # Test
-        self.assertAlmostEqual(actual_mean, reference_mean[0], 2)
+        self.assertEqual(actual_reordered_data, expected_reordered_data)
 
 if __name__ == "__main__":
     # Run the tests

05_testing_and_ci/python_testing_demo.md

@@ -49,8 +49,8 @@ tests/
 - `unittest.main()` provides an option to run the tests from a command-line interface and also from a file.
 - `setUp` function is executed before all the tests. Similar a clean up function `tearDown` exists.
 - The intention is to group together sets of similar tests in an instant of `unittest.TestCase` and have multiple such instances.
+- A unit test for the function `find_median` is written by mocking the function `reorder_data` using [MagicMock](https://docs.python.org/3/library/unittest.mock.html#magic-mock) from unittest. The function `reorder_data` is mocked so that the function `find_median` can be tested in isolation.
 - Decorators such as `@unittest.skip`, `@unittest.skipIf`, `@unittest.expectedFailure` can be used to gain flexibility over working of tests.
-- `unittest.TestCase.subTest` can be used to distinguish parameters inside the body of a test.
 
 ## coverage
 

05_testing_and_ci/python_testing_slides.md

@@ -47,6 +47,7 @@ slideOptions:
 - Python framework specifically designed to run, monitor and automate unit tests.
 - Many features like test automation, sharing of setup and shutdown of tests, etc.
 - Use the base class `unittest.TestCase` to create a test suite.
+- `MagicMock` from `unittest.mock` used for mock testing.
 - Command-line interface: `python -m unittest test_module1 test_module2 ...`.
 - Part of the Python standard library.
 

timetable.md

@@ -120,4 +120,4 @@
 
 ## 12.2 – Wed, January 14, 2025
 
-- **90** min.: [Exercise: Testing Python Code](https://github.com/Simulation-Software-Engineering/Lecture-Material/blob/main/05_testing_and_ci/python_testing_exercise.md)
+- **90** min.: [Exercise: Testing Python Code](https://github.com/Simulation-Software-Engineering/Lecture-Material/blob/main/05_testing_and_ci/python_testing_exercise.md)