What does integration testing evaluate?

Integration testing specifically focuses on how well different components or systems work together. As systems are built from various modules or external interfaces, it is crucial to verify that these components collaborate correctly during their interactions. This form of testing helps identify issues related to the interfaces between the integrated parts, such as data handling, communication protocols, and how each module passes data or control to another.

In this phase, test cases are designed to ensure that components which have been individually tested successfully can function properly when combined. This evaluation may uncover problems that do not appear during unit testing, as those tests typically evaluate individual parts in isolation. By confirming that integrated systems cooperate effectively and yield the expected outcomes, integration testing plays a critical role in ensuring the overall system integrity and functionality.

The other options address different aspects of software testing. Usability testing, for example, focuses on how user-friendly and intuitive the application is for its intended audience. Security testing is concerned with identifying vulnerabilities that may lead to breaches or unauthorized access, while performance testing examines how well the application functions under various loads and stress conditions. Each of these areas is essential in the software development lifecycle, but they pertain to distinct testing methodologies compared to integration testing.