What type of testing is Susan planning to conduct to verify communications and error handling in her e-commerce application?

Susan is planning to conduct interface testing to verify communications and error handling in her e-commerce application. Interface testing specifically focuses on the interactions between different components of the application. This type of testing checks how well the various modules and subsystems communicate with each other, ensuring that data is correctly transmitted and received. It evaluates the correctness of APIs, user interfaces, and data exchange formats, making it essential for detecting issues related to communication between systems and components.

In the context of an e-commerce application, effective interface testing is crucial for confirming that user inputs are properly handled and that errors are reported accurately. This provides a seamless experience for users, which is particularly important in a commercial environment where trust and reliability are key.

While other testing types like unit testing, stress testing, and integration testing have their own specific purposes, they do not primarily focus on the communication between components in the same way that interface testing does. Unit testing deals with individual parts or functions, stress testing evaluates how the system performs under extreme conditions, and integration testing checks how different modules work together. Therefore, interface testing is most aligned with Susan's intention to verify communications and error handling in her application.