What is the method called that tests an application without internal knowledge of the code?

The method that tests an application without knowledge of its internal code is known as black-box testing. This approach focuses on the inputs and outputs of the application, evaluating the functionality based on specified requirements and use cases, rather than delving into the underlying workings of the code itself.

Black-box testing is advantageous because it simulates how an end user would interact with the application, ensuring that the software behaves as expected in real-world situations. Testers design test cases based on specifications and requirements, allowing them to verify the user experience and the application's response to various inputs without needing to understand the implementation details. This method is essential in validating the functionality of an application from the user's perspective, uncovering issues that might not be evident through code inspections or analysis.

The other methods, such as white-box testing, are based on knowledge of the internal code and logic of the application, focusing on testing the paths, branches, and internal structures. Integration testing and system testing also include different aspects of testing, primarily focusing on evaluating the interaction of components and the entire system's operation, respectively, rather than the black-box perspective of user interaction.