Which testing approach is characterized by using full internal knowledge of code and architecture?

• A. Black-box testing.
• B. Gray-box testing.
• C. Limited-scope testing with partial knowledge.
• D. White-box testing.

Answer: (D)

White-box testing is defined by having full access to the code and system design. When testers know the internal structure, they can design tests that traverse specific paths, exercise every branch, and monitor how data moves through the program. This lets them verify that the implementation behaves correctly under particular conditions, ensure security checks and input validations work, and measure code coverage to avoid missed critical areas. This level of internal visibility contrasts with external-only testing and partial-knowledge testing. So using full internal knowledge of code and architecture aligns with white-box testing.