What does test coverage measure in a software project?

• A. The percentage of code exercised by tests
• B. The number of test cases written
• C. The duration of the test suite
• D. The frequency of test runs

Answer: (A)

Test coverage measures how much of the codebase is exercised by the test suite. It’s usually shown as a percentage and can apply to different levels like statements, branches, or paths that are executed when tests run. This helps you see which parts of the code aren’t being touched by tests, guiding you to add or improve tests in those areas. Keep in mind that high coverage doesn’t guarantee bugs won’t slip through, since tests also need meaningful assertions and to cover real edge cases. The other options describe different aspects—how many tests exist, how long the tests take, or how often you run them—not how much of the code is exercised. So the measure of test coverage is the percentage of code exercised by tests.