Shift-Left Testing
1. Introduction
Shift-left is a key concept in modern software testing and DevOps. It focuses on performing test activities earlier in the software development lifecycle (SDLC) to reduce risk and overall cost.
Shift-left는 현대 소프트웨어 테스팅과 DevOps에서 매우 중요한 개념입니다. 테스트 활동을 SDLC의 앞단계로 이동시켜 결함을 조기에 발견하고 비용을 줄이는 것을 목표로 합니다.
2. Key Concept: What Does Shift-Left Mean?
Shift-left means:
- Starting testing activities earlier in the SDLC
- Detecting defects sooner, when they are cheaper to fix
- Reducing the number of defects found late in development
Although shift-left may require more effort and cost early, it usually results in greater savings overall.
Shift-left의 핵심은 다음과 같습니다.
- 테스트를 개발 생명주기 초기에 시작
- 수정 비용이 적은 시점에 결함 발견
- 후반 단계에서 발견되는 결함 수 감소
3. Practice Question
❓ Question
Which of the following provides the BEST description of shift-left?
- a) When agreed by the developers, manual activities on the left-hand side of the test process are automated to support the principle of ‘early testing saves time and money’
- b) Where cost-effective, test activities are moved earlier in the software development lifecycle (SDLC) to reduce the total cost of quality by reducing the number of defects found later in the SDLC
- c) When they have spare time available, testers are required to automate tests for regression testing, starting with component tests and component integration tests
- d) When available, testers are trained to perform tasks early in the SDLC to allow more test activities to be automated later in the SDLC
✅ Correct Answer: b)
4. Explanation (EN / KR)
✔ b) Moving test activities earlier in the SDLC — Correct
This option accurately describes shift-left. Testing is intentionally started earlier in the SDLC to:
- find defects sooner
- reduce rework
- lower the total cost of quality
Although this may require additional training and effort early on, the overall project cost is usually reduced.
이 선택지는 shift-left의 정의를 가장 정확하게 설명합니다. 테스트 활동을 SDLC 앞단계로 이동시켜 결함을 조기에 발견하고, 재작업과 전체 품질 비용을 줄이는 것이 핵심입니다.
❌ a) Automating the “left-hand side of the test process” — Incorrect
Shift-left refers to the SDLC timeline, not to a “left-hand side” of the test process. There is no formal concept of a left-hand side of the test process.
Shift-left는 SDLC의 시간 흐름(왼쪽 → 오른쪽)을 의미합니다. ‘테스트 프로세스의 왼쪽’이라는 개념은 ISTQB에서 정의된 용어가 아닙니다.
❌ c) Testers automating regression tests in spare time — Incorrect
Automated component and integration tests are valuable, but they are usually created by developers and integrated into CI/CD pipelines.
This activity alone does not define shift-left.
회귀 테스트 자동화는 중요하지만, 이는 보통 개발자 책임이며 CI/CD의 일부입니다. 이 자체가 shift-left의 정의는 아닙니다.
❌ d) Training testers early to automate later — Incorrect
Training testers early can support shift-left, but the goal of shift-left is not to automate more tests later in the SDLC.
테스터를 조기에 교육하는 것은 shift-left를 지원할 수는 있지만, shift-left의 목적은 후반 자동화를 늘리는 것이 아닙니다.
5. Summary Table
| Option | Result | Key Idea | 한글 요약 |
|---|---|---|---|
| b | ✔ Correct | Move testing earlier to reduce cost and risk | 테스트를 앞당겨 비용·리스크 감소 |
| a | ✖ | Incorrect concept of “left-hand side” | 잘못된 용어 사용 |
| c | ✖ | Regression automation ≠ shift-left | 회귀 자동화는 shift-left 아님 |
| d | ✖ | Focuses on later automation, not early testing | 후반 자동화 중심 설명 |
6. Final Takeaway
For ISTQB exams, remember:
Shift-left means starting testing earlier in the SDLC to reduce overall cost and risk.
시험에서는 다음 한 문장으로 정리하세요.
Shift-left는 테스트를 SDLC 앞단계로 이동시켜 전체 비용과 리스크를 줄이는 것이다.
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