Path coverage in Testing Fundamentals - Test Execution Trace

Test Overview

This test checks that all possible paths in a simple decision function are executed and verified. It ensures the function behaves correctly for different input values, covering every branch.

Test Code - unittest

Testing Fundamentals

def classify_number(num):
    if num > 0:
        return "Positive"
    elif num == 0:
        return "Zero"
    else:
        return "Negative"

import unittest

class TestClassifyNumber(unittest.TestCase):
    def test_positive(self):
        self.assertEqual(classify_number(5), "Positive")

    def test_zero(self):
        self.assertEqual(classify_number(0), "Zero")

    def test_negative(self):
        self.assertEqual(classify_number(-3), "Negative")

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

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Test runner initialized, tests ready to execute	-	PASS
2	Runs test_positive: calls classify_number(5)	Function receives input 5	Return value is 'Positive'	PASS
3	Runs test_zero: calls classify_number(0)	Function receives input 0	Return value is 'Zero'	PASS
4	Runs test_negative: calls classify_number(-3)	Function receives input -3	Return value is 'Negative'	PASS
5	All tests complete	All paths in classify_number covered	All assertions passed	PASS

Failure Scenario

Failing Condition: Function returns wrong classification for any input path

Execution Trace Quiz - 3 Questions

What does the test_positive method verify?

A That classify_number returns 'Zero' for input zero

B That classify_number returns 'Positive' for input greater than zero

C That classify_number returns 'Negative' for input less than zero

D That classify_number raises an error for negative input

Key Result

Path coverage testing ensures every possible route through the code is tested, catching errors in all decision branches.