Integration testing in Testing Fundamentals - Test Execution Trace

Test Overview

This test checks if two parts of a simple calculator app work well together. It verifies that adding two numbers through the combined modules returns the correct result.

Test Code - unittest

Testing Fundamentals

import unittest

# Module A: simple adder function
def add(a, b):
    return a + b

# Module B: calculator uses add function
def calculate_sum(x, y):
    return add(x, y)

class TestIntegrationCalculator(unittest.TestCase):
    def test_addition_integration(self):
        result = calculate_sum(3, 4)
        self.assertEqual(result, 7, "Sum should be 7")

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

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Test runner initialized, test class loaded	-	PASS
2	Calls calculate_sum(3, 4)	Calculator module ready to use add function	-	PASS
3	calculate_sum calls add(3, 4)	Adder module receives inputs 3 and 4	-	PASS
4	add returns 7	Adder module returns result 7	-	PASS
5	calculate_sum returns 7 to test	Calculator module returns final result	-	PASS
6	Test asserts result == 7	Test compares actual result with expected 7	assertEqual(7, 7)	PASS
7	Test ends successfully	Test runner reports test passed	-	PASS

Failure Scenario

Failing Condition: Adder function returns wrong sum or calculate_sum does not call add correctly

Execution Trace Quiz - 3 Questions

What does the integration test verify?

A That the add function alone returns correct sums

B That two modules work together to add numbers correctly

C That the test framework runs without errors

D That the calculator UI displays results

Key Result

Integration testing ensures that separate parts of a system work together correctly, catching issues that unit tests alone might miss.