4.1 Test Techniques Overview
Purpose of Test Techniques
Test techniques are used to:
- Design effective test cases
- Reduce the number of test cases
- Increase test coverage
- Detect defects efficiently
Categories of Test Techniques (★★★★★ MUST MEMORIZE)
- Black-box (Specification-based): Focus on inputs and outputs
- White-box (Structure-based): Focus on the internal code
- Experience-based : Focus on the tester's knowledge
시험에서는 이 3개를 섞어서 물어봅니다.
4.2 Black-Box Test Techniques (★★★★★ )
Black-box techniques:
- Based on requirements / specifications
- No knowledge of internal code structure
1. Equivalence Partitioning (EP)
Idea
- Divide input data into equivalence partitions
- Test one value per partition
Types
Example
Input: Age 18–65
- Valid: 18–65
- Invalid: <18, >65
시험 포인트
“Reduces number of test cases” → EP
2. Boundary Value Analysis (BVA)
Idea
- Defects often occur at boundaries
- Test values at the edges
Typical values
Example
Range: 1–100 => Test: 1, 2, 99, 100
Exam favorite
“MOST effective for boundary defects” → BVA
EP vs BVA (시험 단골 비교)
| EP | BVA |
|---|---|
| Any value in partition | Boundary values |
| Fewer test cases | More defect-focused |
| General reduction | Edge-focused |
3. Decision Table Testing
Used when
- Business rules
- Multiple conditions and actions
Key point
- Tests combinations of conditions
Exam phrase
“Complex business logic” → Decision table
4. State Transition Testing
Used when
- System behavior depends on states
- Valid/invalid transitions matter
Examples
- ATM
- Login system
- Traffic light
Watch for words: state, transition, event
5. Use Case Testing
Focus
- End-to-end user scenarios
- User interactions
Based on
4.3 White-Box Test Techniques (★★★ Important)
White-box techniques:
- Based on internal structure
- Require code knowledge
Statement Coverage
Goal
- Each executable statement executed at least once
- High coverage ≠ defect-free (exam trap)
Branch (Decision) Coverage
Goal
- Each decision outcome (true/false) executed
- Branch coverage is stronger than statement coverage
Coverage Key Trap
100% coverage does NOT guarantee no defects
4.4 Experience-Based Test Techniques (★★★)
Based on:
Error Guessing
- Based on intuition and past defects
- No formal rules
Exploratory Testing
- Test design and execution occur simultaneously
- Often time-boxed
- Useful when documentation is limited
Exam phrase
“Simultaneous learning, test design, and execution”
Chapter 4 – 시험 직전 암기 포인트 (★★★★★)
무조건 기억:
- EP → partitions
- BVA → boundaries
- Decision table → business rules
- State transition → states/events
- Statement vs Branch coverage
- Exploratory testing = simultaneous
VERY COMMON EXAM TRAPS
- “Black-box needs code knowledge” ❌
- “100% coverage = no defects” ❌
- “Exploratory testing is unstructured” ❌ (it is structured, but flexible)
- “EP focuses on boundaries” ❌
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