What is Test Coverage?

Test coverage is a metric used in software quality assurance to measure the extent to which a software system has been tested. It refers to the percentage of code or functionality that has been exercised by a set of test cases. Test coverage helps in determining the effectiveness and thoroughness of the testing process by identifying areas of the software that have not been adequately tested.

There are different types of test coverage, including statement coverage, branch coverage, path coverage, and condition coverage. Statement coverage measures the percentage of code statements that have been executed during testing. Branch coverage measures the percentage of decision points (branches) that have been taken during testing. Path coverage measures the percentage of unique paths through the code that have been executed. Condition coverage measures the percentage of Boolean conditions that have been evaluated to both true and false during testing.

Test coverage is important because it helps in identifying areas of the software that have not been tested, allowing testers to focus on those areas and improve the overall quality of the software. It also helps in identifying potential defects and vulnerabilities that may exist in untested parts of the code. Test coverage can be used as a measure of the testing effort and can help in determining when to stop testing.

However, it is important to note that achieving 100% test coverage does not guarantee that the software is defect-free. It is possible to have high test coverage but still have undiscovered defects. Test coverage should be used in conjunction with other testing techniques and metrics to ensure comprehensive testing and improve the overall quality of the software.