Explore essential concepts of code coverage, including coverage types, metrics interpretation, benefits, and limitations. This quiz helps you assess your understanding of how code coverage informs software quality and software testing strategies.
Which type of code coverage measures whether each individual line of code has been executed during testing?
Explanation: Line coverage specifically tracks the execution of each line in the source code, providing a basic metric of which lines have been tested. Function coverage, by contrast, examines if each function is called during tests. Path coverage deals with all possible routes through the code and is more complex. Integration coverage is focused on interactions between components rather than individual code lines.
A team reports 85% branch coverage on their codebase; what does this percentage represent?
Explanation: Branch coverage measures the extent to which test cases execute all possible branches, such as 'if' or 'else' paths, in the code. It does not mean that 85% of code lines or modules are covered, nor does it imply the code is 85% defect-free. The primary focus is on testing all decision points, which helps uncover logical errors.
Why can a codebase with 100% code coverage still contain undetected bugs?
Explanation: Even if every line or branch is executed during tests, the tests may not assert the correct behavior or cover unusual inputs. Code coverage only measures which code runs, not whether the outcomes are correct. It does not guarantee code perfection or bug-free status. Additionally, code coverage can be measured for many language types, not just compiled ones.
If a function has an 'if-else' block and your tests only trigger the 'if' condition, what aspect of coverage are you missing?
Explanation: Without tests that trigger both the 'if' and 'else' branches, not all decision branches are tested, so branch coverage is incomplete. Line coverage might still be considered adequate if both branches are on separate lines and only one is executed. Syntax and performance coverage are not standard code coverage types relevant to this scenario.
Which is a primary benefit of monitoring code coverage metrics throughout a project's lifecycle?
Explanation: Tracking coverage over time enables teams to identify areas of the codebase not exercised by tests, especially as the code evolves. While useful, code coverage does not guarantee the absence of bugs, replace the need for code reviews, or generate test cases. It supports quality by highlighting gaps, but does not by itself ensure comprehensive testing.