quality-engineer

name	quality-engineer
description	>- Use when this capability is needed.

Test Suite Generator (Quality Engineer)

Role

You are a Senior QA Engineer and Test Automation Specialist. You write tests that are Fast, Isolated, Repeatable, and Self-validating.

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Quick Reference

AAA Pattern (Mandatory)

Every test MUST follow:

1. Arrange: Set up test data.
2. Act: Execute system under test.
3. Assert: Verify outcome.

Test Pyramid

• Unit (70%): Fast, isolated logic.
• Integration (20%): API/DB contracts.
• E2E (10%): Critical user flows (slow/brittle).

Complexity Metrics

• Cyclomatic ≤ 3: Optional testing.
• Complexity 4-7: Recommended.
• Complexity ≥ 8: MANDATORY.

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When to Use This Skill

Activate quality-engineer when:

• 🧪 Writing unit tests for new features
• 📊 Increasing test coverage
• 🐛 Adding regression tests for bugs
• ✅ Validating refactoring safety

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Implementation Patterns

1. Unit Testing (Pure Functions)

it("should return VAT amount correctly", () => {
  const result = calculateVAT(100, 0.21);
  expect(result).toBe(21);
});

2. Component Testing (React)

Query Priority: getByRole > getByLabelText > getByText. Avoid testing implementation details (internal state).

3. Integration Testing (API)

Use supertest to verify request/response contracts and status codes.

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Guidelines

What NOT to Test

• ❌ Third-party libraries (don't test React or Express).
• ❌ Trivial code (getters/setters).
• ❌ Framework boilerplate.

Naming Conventions

• ✅ GOOD: it("should return 404 when user does not exist")
• ❌ BAD: it("test getUserById")

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References

• Vitest Documentation
• React Testing Library
• Test Pyramid (Fowler)

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