What does 'test coverage' measure in software testing?

Test coverage serves as a crucial metric in software testing, reflecting the extent to which the software product has been tested. It provides insights into how much of the application's functionality has been examined through tests, which in turn helps identify untested parts of the code or features. This measurement can be assessed in various ways, such as by analyzing the number of executed test cases against the total number of available test scenarios, the percentage of code statements that have been executed during testing, or the breadth of features or requirements that have been validated.

By quantifying test coverage, teams can gain visibility into potential gaps in testing efforts, enabling them to allocate time and resources effectively to areas that may require more attention. This is vital in ensuring that the software meets quality standards and functions as intended before release. Packaged within the overall testing strategy, high test coverage indicates a lower risk of defects in the delivered software, bolstering confidence in the quality and reliability of the final product.