Which testing technique focuses on evaluating the internal workings of an application?

The focus of white box testing is on evaluating the internal workings of an application. This approach allows testers to have full knowledge of the source code, architecture, and implementation details, enabling them to design test cases that thoroughly examine the logic, structure, and flow of the application. Testers can check for vulnerabilities, coding errors, and other issues that could compromise security or performance by having access to the internal operations.

White box testing is particularly useful for ensuring that individual components function as intended and that the overall software behaves correctly under various operating conditions. It provides a solid understanding of how different components interact, making it easier to identify areas that require improvements or where potential vulnerabilities may exist.

In contrast, black box testing evaluates an application based purely on its functionality without any knowledge of the internal workings. Unit testing focuses on testing individual components or functions independently, while functional testing assesses the system against defined specifications without delving into the internal code logic. Thus, while all these testing methods are important in a comprehensive testing strategy, only white box testing provides the detailed examination of an application's inner workings.