問42
頻出度★★★
入力と出力だけに着目して様々な入力に対して仕様書どおりの出力が得られるかどうかを確認していく, システムの内部構造とは無関係に外部から見た機能について検証するテスト方法はどれか。
平成21年度 春期 ITパスポート試験 問42
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 42
Incorrectア
Operational testing is the name of a testing stage (phase) in which the system is run under the actual operating environment and operating procedures, and the users themselves make the final check that it can be used for their work. It sits at the end of the development flow of unit testing → integration testing → system testing → operational testing, and it is not a term that classifies testing techniques by whether they focus only on inputs and outputs or also look at the internal structure. It therefore does not match the definition given in the question.
Incorrectイ
Integration testing is the name of a testing stage in which several modules (program parts) that have finished unit testing are combined, and the data passed between them and their interfaces are checked to confirm that they work together correctly. This too is a division into stages, not a classification based on whether you look at the internal structure or only at inputs and outputs from the outside. In fact, black-box testing techniques can be used inside integration testing, so the two are not concepts that line up on the same axis.
- ウ
正解 The correct answer is ウ. Black-box testing treats the inside of a program as a black box that cannot be seen into. It does not go into the internal logic or the source code at all, and only checks from the outside whether the output returned for a given input matches what the specification states. The three conditions in the question — focusing only on inputs and outputs, being independent of the system's internal structure, and verifying the functionality as seen from the outside — are all restatements of the very definition of black-box testing, and no other choice can satisfy them. The basis for the judgement is the specification (the external specification), and test cases are also created from the specification. Typical design techniques are equivalence partitioning, which divides input values into groups that produce the same result and tries one representative value from each group, and limit-value analysis (boundary value analysis), which concentrates on values at the borders between those groups.
Incorrectエ
White-box testing treats the internal structure of a program (its control flow, branches, and statements) as a white box that can be seen into, and verifies the logic of the source code, creating test cases according to coverage criteria such as statement coverage and branch coverage. It directly contradicts the condition stated in the question, namely that the method is independent of the system's internal structure, so it is wrong. It is exactly the counterpart of black-box testing.
ここがポイント
- Black-box testing = a technique that does not look at the internal structure and verifies from the outside whether inputs and outputs match the specification. Test cases are created from the specification, and typical design techniques are equivalence partitioning and limit-value analysis (boundary value analysis). Its counterpart, white-box testing, focuses on the internal logical structure and verifies it with criteria such as statement coverage and branch coverage.
- Do not confuse a testing technique (what you focus on when checking) with a testing stage (at which point in development it is carried out). Black-box and white-box are a classification of techniques, while unit testing, integration testing, system testing, and operational testing are a classification of stages, so they are terms on a different axis.
用語