Understanding What Code Coverage Shows

Code coverage is a metric that helps Developers and teams understand how much of the source code has been exercised by automated tests. It is a crucial measure for ensuring that the codebase is thoroughly tested, which can reduce the likelihood of undetected defects.

Exam Question

What does Code Coverage show?
(choose the best answer)
A. The absence of defects in code.
B. When a feature is done.
C. The quality of unit tests being written.
D. The ratio of the number of tests to lines of code in the system being tested.
E. Code being exercised by tests.

Correct Answer

E. Code being exercised by tests.

Explanation

Correct Answer

E. Code being exercised by tests:
Code coverage measures the extent to which the source code is executed during testing. It provides insight into which parts of the codebase have been tested, ensuring that critical paths in the code are exercised by tests. This helps identify areas of the code that may not be covered by existing tests, highlighting potential risks or areas that need additional testing.

Why the Other Options Are Incorrect

A. The absence of defects in code:
Code coverage does not guarantee that the code is defect-free. High code coverage means that a large portion of the code has been tested, but it does not ensure that the tests are effective in catching all potential defects.

B. When a feature is done:
Code coverage is not a measure of feature completion. It only indicates the extent to which the code has been tested, not whether a feature is fully implemented or ready for release.

C. The quality of unit tests being written:
While code coverage can indicate which parts of the code are being tested, it does not directly measure the quality of those tests. Quality of tests is determined by how well they validate the correctness and robustness of the code, not just by their presence.

D. The ratio of the number of tests to lines of code in the system being tested:
Code coverage does not measure the ratio of tests to lines of code. Instead, it measures how much of the code has been executed by the tests, regardless of the number of tests.

Relevance to the PSD Exam

Understanding what code coverage measures is crucial for the PSD exam. It emphasizes the importance of ensuring that your codebase is thoroughly tested, which helps maintain high quality and reduces the risk of defects.

Key Takeaways

• Code Coverage: Indicates which parts of the code are being tested, ensuring that key paths in the codebase are exercised by tests.
• Testing Effectiveness: While code coverage is important, it must be complemented with effective test cases to ensure comprehensive quality assurance.

Conclusion

Code coverage is a valuable metric that shows the extent to which your code has been tested, helping to identify untested areas that may be risky. However, high code coverage alone does not guarantee code quality; it must be paired with well-designed tests. For more information on preparing for the PSD exam, visit our Professional Scrum Developer PSD™ Exam Prep.