What does non-functional testing assess in a system?

Non-functional testing plays a crucial role in evaluating the quality attributes of a system beyond its basic functionalities. It focuses on various aspects, such as usability, reliability, performance, and security, among others. This type of testing helps ensure that the system not only works as intended but also meets the necessary standards for efficiency and user experience, significantly impacting user satisfaction and system performance in real-world scenarios.

For instance, while functional testing would confirm that a feature works (like logging into an application), non-functional testing would assess how quickly that login occurs under various load conditions, how intuitive the login interface is for users, and whether the application remains reliable under stress. Overall, non-functional testing is essential for delivering a well-rounded, high-quality product that performs well in diverse situations.