What testing approach uses complete access to the target system, including internal details?

• A. White-Box Testing
• B. Black-Box Testing
• C. Grey-Box Testing
• D. Penetration Testing

Answer: (A)

The concept being tested is white-box testing: testing with full visibility into the system’s internals. When testers have complete access to internal details—such as source code, architecture, data structures, and internal workflows—they can design tests that exercise specific code paths, validate logic, and verify how components interact under different states. This level of access makes it possible to perform thorough coverage, catch path-specific defects, and locate the exact points of failure quickly. It’s the ideal approach when the goal is to validate internal correctness and ensure that the implementation behaves as intended from inside out. In contrast, black-box testing uses no internal visibility and focuses on external behavior, grey-box testing provides partial knowledge, and penetration testing concentrates on security through simulated attacks rather than exhaustive code-level verification.