Which of the following is NOT a white-box test design technique?

• A. Control flow testing
• B. Path testing
• C. Boundary value testing
• D. Branch testing

Answer: (C)

White-box testing designs rely on the program’s internal structure, guiding tests to exercise specific code paths, decision points, and branches. Control flow testing aims to cover the sequence of statements as dictated by the code. Path testing pushes coverage toward as many distinct execution paths as possible. Branch testing ensures every conditional outcome is exercised, so both true and false branches are validated.

Boundary value testing, by contrast, derives test cases from the edges of input domains—min, max, and just-inside/just-outside values—focusing on how the software behaves at limits rather than how the code is structured. It targets external behavior dictated by input ranges and is typically considered black-box. Therefore, boundary value testing is not a white-box test design technique. For example, if a function accepts 1 to 100, boundary value testing would examine values like 1, 100, 0, 2, 99, and 101 to catch edge-case issues.