How does end-to-end testing differ from unit testing?

End-to-end testing is a comprehensive testing approach that evaluates the overall application workflow to ensure that all components work together as expected in a real-world scenario. This type of testing simulates user interactions and tests the entire system from start to finish, effectively validating that the business processes function correctly across various systems and interfaces.

In contrast to unit testing, which focuses on individual units or components of the software to verify that each part performs as intended in isolation, end-to-end testing verifies that the integrated components function correctly together, reflecting a complete and realistic environment. This holistic perspective is essential for ensuring that the application delivers the intended user experience and meets the business requirements.

The other options provide limited or inaccurate aspects of what end-to-end testing entails. For instance, it does not focus solely on specific modules nor is it confined to automated testing of user interfaces only. Furthermore, while some end-to-end tests may require manual interaction, many can also be automated, so this statement does not define the methodology clearly. Therefore, focusing on the overall application workflow encapsulates the fundamental essence of end-to-end testing accurately.