Which framework is primarily concerned with testing each component in isolation?

The Unit Test Framework is primarily concerned with testing individual components or units of code in isolation from the rest of the application. This approach allows testers and developers to focus on verifying that each component behaves as expected, without the influence of other parts of the system.

By isolating components, unit testing can identify and address bugs at an early stage of development, contributing to more robust and reliable software. Unit tests typically involve testing functions, methods, or classes to ensure that they perform correctly under various conditions, which helps to confirm that the underlying logic is sound before integrating these components into larger systems.

In contrast, other frameworks like the integration testing framework focus on how multiple components work together, system testing framework assesses the overall system behavior and performance, and end-to-end testing framework evaluates the entire application flow from start to finish. Each of these frameworks has its own objectives and scope but does not center solely on the isolated testing of individual components like the unit test framework does.