Defect density and detection rate in Testing Fundamentals - Test Execution Trace

Test Overview

This test calculates defect density and detection rate for a software module. It verifies that the calculations match expected values based on given defect counts and lines of code.

Test Code - unittest

Testing Fundamentals

import unittest

class TestDefectMetrics(unittest.TestCase):
    def test_defect_density_and_detection_rate(self):
        total_defects_found = 25
        total_lines_of_code = 5000
        total_defects_reported = 30

        # Calculate defect density (defects per 1000 lines of code)
        defect_density = total_defects_found / (total_lines_of_code / 1000)

        # Calculate detection rate (percentage of defects found vs reported)
        detection_rate = (total_defects_found / total_defects_reported) * 100

        # Assert defect density is as expected
        self.assertAlmostEqual(defect_density, 5.0, places=2)

        # Assert detection rate is as expected
        self.assertAlmostEqual(detection_rate, 83.33, places=2)

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

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Test framework initializes and prepares to run test_defect_density_and_detection_rate	-	PASS
2	Assign total_defects_found = 25, total_lines_of_code = 5000, total_defects_reported = 30	Variables set with given values	-	PASS
3	Calculate defect_density = 25 / (5000 / 1000) = 5.0	defect_density calculated as 5.0 defects per 1000 lines	-	PASS
4	Calculate detection_rate = (25 / 30) * 100 = 83.33	detection_rate calculated as 83.33%	-	PASS
5	Assert defect_density equals 5.0 within 2 decimal places	defect_density is 5.0	defect_density == 5.0	PASS
6	Assert detection_rate equals 83.33 within 2 decimal places	detection_rate is 83.33	detection_rate == 83.33	PASS
7	Test ends successfully	All assertions passed, test completes	-	PASS

Failure Scenario

Failing Condition: If defect_density or detection_rate calculations do not match expected values

Execution Trace Quiz - 3 Questions

What does the test verify about defect density?

A It checks defect density equals 5 defects per 1000 lines of code

B It checks defect density is less than 10

C It checks defect density is a whole number

D It checks defect density equals total defects found

Key Result

Always verify calculations of quality metrics like defect density and detection rate with precise assertions to catch errors early.