Why Regression Tests Need Updates
1. Introduction
In iterative and incremental development, regression testing is essential. If regression tests never change and suddenly stop finding defects, this can be a warning sign. This question explores which testing principle explains why a tester might feel skeptical even though all tests passed.
[한국어 요약]
반복적·증분 개발에서 회귀 테스트가 늘 동일하고 결함이 계속 발견되지 않는다면 문제일 수 있습니다.
본 문제는 어떤 테스트 원리가 이러한 의심을 설명하는지 묻습니다.
2. Sample Question
You have been assigned as a tester to a team producing a new system incrementally. You noticed that regression test cases have not changed for several iterations, and no new regression defects were found. Your manager is happy, but you are not. Which testing principle explains your skepticism?
- a) Tests wear out
- b) Absence-of-defects fallacy
- c) Defects cluster together
- d) Exhaustive testing is impossible
3. Correct Answer
✔ Correct Answer: a)
The principle "tests wear out" states that if the same tests are repeated many times, they eventually stop detecting new defects. This happens because the tests no longer reflect new system changes or new risk areas. Your skepticism is justified — the regression suite may simply be outdated.
[한국어 요약]
정답은 a)입니다. 동일한 테스트를 반복하면 더 이상 새로운 결함을 찾지 못하는 현상을 설명하는 원리가 바로 “Tests wear out”입니다.
4. Why the Other Options Are Not Correct
b) Absence-of-defects fallacy
Not correct. This principle warns against the belief that fixing many defects means the system will succeed. It does not explain why unchanged tests stop finding issues.
[한국어 요약]
b는 틀렸습니다. “결함이 없다고 성공이 보장되지 않는다”는 의미이지, 반복 테스트와 관련된 원리는 아닙니다.
c) Defects cluster together
Not correct. This principle means that defects tend to concentrate in a few components. It is unrelated to regression tests becoming ineffective with repetition.
[한국어 요약]
c는 틀렸습니다. 결함이 특정 부분에 몰리는 경향을 말할 뿐, 회귀 테스트 반복 문제와 연결되지 않습니다.
d) Exhaustive testing is impossible
Not correct. This principle states that testing every combination of inputs and conditions is impossible. It does not relate to why repeated tests no longer find new defects.
[한국어 요약]
d는 틀렸습니다. 모든 입력 조합을 테스트하는 것은 불가능하다는 뜻이지만, 본 시나리오와는 무관합니다.
5. Summary
If regression tests never change, they eventually lose their effectiveness. This reflects the principle "tests wear out". To improve coverage, teams should regularly update regression tests to match new features and risks. refer to FL-1.3.1
[한국어 요약]
회귀 테스트가 오래도록 동일하면 효율이 떨어집니다.
“Tests wear out” 원리에 따라 테스트 케이스를 주기적으로 갱신해야 합니다.
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