If you are testing a complex user flow involving multiple widgets and backend interactions, what type of test would be most appropriate?

End-to-End Testing would be the most appropriate type of test in this situation. End-to-End Testing involves testing the entire application flow, including interactions between widgets and backend services. It provides a comprehensive assessment of the system's behavior in a real-world scenario. This type of testing is crucial for ensuring that the entire application stack, from the user interface to backend services, works seamlessly together and delivers the expected user experience.