Which process is described as testing with knowledge of the internal structure of the software?

White Box Testing is a methodology in software testing that involves testing the internal structures or workings of an application, as opposed to its functionality (which is what Black Box Testing would focus on). In White Box Testing, testers have access to the internal code and logic of the software, enabling them to create test cases based on the internal workings and to ensure that specific paths through the code are properly executed.

This type of testing allows for more thorough examination, including coverage of the various loops, branches, and conditions in the software. It is particularly beneficial for evaluating the correctness of algorithms, data flow, and overall code quality. The understanding of the internal structure helps testers identify logical errors and inefficiencies that may not be evident through functional testing alone.

In contrast, User Acceptance Testing focuses on validating the software against user requirements without any insight into the code itself. Regression Testing is conducted to confirm that recent changes haven't adversely affected existing functionality, typically without requiring knowledge of the internal structure. Beta Testing involves releasing the software to a limited audience outside the development team to gather feedback before the final release, which again does not involve an understanding of the internal workings of the software.