What distinguishes white-box testing from black-box testing?

White-box testing is characterized by its focus on the internal workings of an application, requiring knowledge of the code, architecture, and logic behind the software. Testers understand how the application is structured and can create test cases that verify the accurate functioning of specific paths and logic branches within the code. This approach allows for detailed examination of the software, such as checking for proper variable handling, control flow, and data manipulation.

In contrast, white-box testing is fundamentally different from black-box testing, where testers do not have access to the internal structure or implementation details of the software. Instead, black-box testing evaluates the software solely based on its input and output, emphasizing functionality from a user perspective rather than internal mechanisms. By focusing on the internal components, white-box testing provides a more in-depth assessment of the software's reliability, security, and performance, particularly in areas that might be invisible to end-users during black-box testing.