Learn in the textbookTest Techniques and Integration/Performance Verification
DefinitionBlack-box testing (ブラックボックステスト) is a test technique that ignores the program's internal structure and checks, against the external specification (外部仕様), whether each input produces the correct output.
ExplanationBecause testers build the cases from the specification alone, someone other than the person who wrote the code can design them. A typical method, equivalence partitioning (同値分割), splits the inputs into groups that each lead to the same result and picks a representative value from each group. Boundary value analysis (境界値分析), which focuses on the edges of each range and the values right beside them, can also be built from the specification alone.
AnalogyIt is like testing a calculator by pressing keys and seeing whether the displayed answer is right, without ever opening the case.
Memory hookA black box is painted black so you cannot see inside; all you can watch is what goes in and what comes out.