Which testing approach focuses on the internal workings of an application?

The testing approach that focuses on the internal workings of an application is white box testing. This method requires a thorough understanding of the internal logic and structure of the code. Testers use their knowledge of the internal mechanisms to design test cases that explore different paths through the application, evaluate the flow of inputs and outputs, and assess how well the code is structured and implemented.

White box testing allows for more detailed testing of individual functions and algorithms, as it involves looking at the code itself. It is commonly used for unit testing and helps identify issues such as logic errors, code branching conditions, and security vulnerabilities. Since this testing approach examines the internal state and structure of the application, it is essential for ensuring that specific parts of the software behave as expected under various conditions.