test-design-techniques
🎯Skillfrom proffesor-for-testing/agentic-qe
|Systematically designs comprehensive test cases using boundary value analysis, equivalence partitioning, and other techniques to reduce redundant tests and ensure systematic test coverage.
Installation
npx skills add https://github.com/proffesor-for-testing/agentic-qe --skill test-design-techniquesSkill Details
"Systematic test design with boundary value analysis, equivalence partitioning, decision tables, state transition testing, and combinatorial testing. Use when designing comprehensive test cases, reducing redundant tests, or ensuring systematic coverage."
Overview
# Test Design Techniques
When designing test cases systematically:
- APPLY Boundary Value Analysis (test at min, max, edges)
- USE Equivalence Partitioning (one test per partition)
- CREATE Decision Tables (for complex business rules)
- MODEL State Transitions (for stateful behavior)
- REDUCE with Pairwise Testing (for combinations)
Quick Design Selection:
- Numeric ranges → BVA + EP
- Multiple conditions → Decision Tables
- Workflows → State Transition
- Many parameters → Pairwise Testing
Critical Success Factors:
- Systematic design finds more bugs with fewer tests
- Random testing is inefficient
- 40+ years of research backs these techniques
Quick Reference Card
When to Use
- Designing new test suites
- Optimizing existing tests
- Complex business rules
- Reducing test redundancy
Technique Selection Guide
| Scenario | Technique |
|----------|-----------|
| Numeric input ranges | BVA + EP |
| Multiple conditions | Decision Tables |
| Stateful workflows | State Transition |
| Many parameter combinations | Pairwise |
| All combinations critical | Full Factorial |
---
Boundary Value Analysis (BVA)
Principle: Bugs cluster at boundaries.
Test at boundaries:
- Minimum valid value
- Just below minimum (invalid)
- Just above minimum (valid)
- Maximum valid value
- Just above maximum (invalid)
```javascript
// Age field: 18-120 valid
const boundaryTests = [
{ input: 17, expected: 'invalid' }, // Below min
{ input: 18, expected: 'valid' }, // Min boundary
{ input: 19, expected: 'valid' }, // Above min
{ input: 119, expected: 'valid' }, // Below max
{ input: 120, expected: 'valid' }, // Max boundary
{ input: 121, expected: 'invalid' } // Above max
];
```
---
Equivalence Partitioning (EP)
Principle: One test per equivalent class.
```javascript
// Discount rules:
// 1-10: No discount
// 11-100: 10% discount
// 101+: 20% discount
const partitionTests = [
{ quantity: -1, expected: 'invalid' }, // Invalid partition
{ quantity: 5, expected: 0 }, // Partition 1: 1-10
{ quantity: 50, expected: 0.10 }, // Partition 2: 11-100
{ quantity: 200, expected: 0.20 } // Partition 3: 101+
];
// 4 tests cover all behavior (vs 200+ if testing every value)
```
---
Decision Tables
Use for: Complex business rules with multiple conditions.
```
Loan Approval Rules:
┌──────────────┬───────┬───────┬───────┬───────┬───────┐
│ Conditions │ R1 │ R2 │ R3 │ R4 │ R5 │
├──────────────┼───────┼───────┼───────┼───────┼───────┤
│ Age ≥ 18 │ Yes │ Yes │ Yes │ No │ Yes │
│ Credit ≥ 700 │ Yes │ Yes │ No │ Yes │ No │
│ Income ≥ 50k │ Yes │ No │ Yes │ Yes │ Yes │
├──────────────┼───────┼───────┼───────┼───────┼───────┤
│ Result │Approve│Approve│Reject │Reject │Reject │
└──────────────┴───────┴───────┴───────┴───────┴───────┘
// 5 tests cover all decision combinations
```
---
State Transition Testing
Model state changes:
```
States: Logged Out → Logged In → Premium → Suspended
Valid Transitions:
- Login: Logged Out → Logged In
- Upgrade: Logged In → Premium
- Payment Fail: Premium → Suspended
- Logout: Any → Logged Out
Invalid Transitions to Test:
- Logged Out → Premium (should reject)
- Suspended → Premium (should reject)
```
```javascript
test('cannot upgrade without login', async () => {
const result = await user.upgrade(); // While logged out
expect(result.error).toBe('Login required');
});
```
---
Pairwise (Combinatorial) Testing
Problem: All combinations explode exponentially.
```javascript
// Parameters:
// Browser: Chrome, Firefox, Safari (3)
// OS: Windows, Mac, Linux (3)
// Screen: Desktop, Tablet, Mobile (3)
// All combinations: 3 × 3 × 3 = 27 tests
// Pairwise: 9 tests cover all pairs
const pairwiseTests = [
{ browser: 'Chrome', os: 'Windows', screen: 'Desktop' },
{ browser: 'Chrome', os: 'Mac', screen: 'Tablet' },
{ browser: 'Chrome', os: 'Linux', screen: 'Mobile' },
{ browser: 'Firefox', os: 'Windows', screen: 'Tablet' },
{ browser: 'Firefox', os: 'Mac', screen: 'Mobile' },
{ browser: 'Firefox', os: 'Linux', screen: 'Desktop' },
{ browser: 'Safari', os: 'Windows', screen: 'Mobile' },
{ browser: 'Safari', os: 'Mac', screen: 'Desktop' },
{ browser: 'Safari', os: 'Linux', screen: 'Tablet' }
];
// Each pair appears at least once
```
---
Agent-Driven Test Design
```typescript
// Auto-generate BVA tests
await Task("Generate BVA Tests", {
field: 'age',
dataType: 'integer',
constraints: { min: 18, max: 120 }
}, "qe-test-generator");
// Returns: 6 boundary test cases
// Auto-generate pairwise tests
await Task("Generate Pairwise Tests", {
parameters: {
browser: ['Chrome', 'Firefox', 'Safari'],
os: ['Windows', 'Mac', 'Linux'],
screen: ['Desktop', 'Tablet', 'Mobile']
}
}, "qe-test-generator");
// Returns: 9-12 tests (vs 27 full combination)
```
---
Agent Coordination Hints
Memory Namespace
```
aqe/test-design/
├── bva-analysis/* - Boundary value tests
├── partitions/* - Equivalence partitions
├── decision-tables/* - Decision table tests
└── pairwise/* - Combinatorial reduction
```
Fleet Coordination
```typescript
const designFleet = await FleetManager.coordinate({
strategy: 'systematic-test-design',
agents: [
'qe-test-generator', // Apply design techniques
'qe-coverage-analyzer', // Analyze coverage
'qe-quality-analyzer' // Assess test quality
],
topology: 'sequential'
});
```
---
Related Skills
- [agentic-quality-engineering](../agentic-quality-engineering/) - Agent-driven testing
- [risk-based-testing](../risk-based-testing/) - Prioritize by risk
- [mutation-testing](../mutation-testing/) - Validate test effectiveness
---
Remember
Systematic design > Random testing. 40+ years of research shows these techniques find more bugs with fewer tests than ad-hoc approaches.
Combine techniques for comprehensive coverage. BVA for boundaries, EP for partitions, decision tables for rules, pairwise for combinations.
With Agents: qe-test-generator applies these techniques automatically, generating optimal test suites with maximum coverage and minimum redundancy. Agents identify boundaries, partitions, and combinations from code analysis.
More from this repository10
Automates security vulnerability scanning and penetration testing for n8n workflows, identifying potential risks and misconfigurations.
Validates database schemas, tests data integrity, verifies migrations, checks transaction isolation, and measures query performance.
Delivers unvarnished technical criticism with surgical precision, combining expert-level BS detection and zero-tolerance for low-quality work.
n8n-expression-testing skill from proffesor-for-testing/agentic-qe
Validates n8n workflow triggers by comprehensively testing webhook, schedule, polling, and event-driven mechanisms with robust payload and authentication checks.
Validates n8n integration connectivity, authentication flows, and error handling across external service APIs through comprehensive testing patterns.
Applies Six Thinking Hats methodology to systematically analyze software testing challenges from multiple perspectives, enhancing decision-making and test strategy development.
Prioritizes testing efforts by systematically assessing and ranking risks based on probability and potential impact across software components.
Accelerates software quality by moving testing earlier in development, reducing defect costs through proactive validation, automated testing, and continuous improvement practices.
chaos-engineering-resilience skill from proffesor-for-testing/agentic-qe