claude-code-skills-reference/qa-expert/references/google_testing_standards.md

Google Testing Standards Reference

Comprehensive guide to Google's testing best practices and standards.

---

AAA Pattern (Arrange-Act-Assert)

Every test should follow this structure:

1. Arrange (Setup)

**Prerequisites**:
- System in known state
- Test data prepared
- Dependencies mocked/configured

2. Act (Execute)

**Test Steps**:
1. Perform action
2. Trigger behavior
3. Execute operation

3. Assert (Verify)

**Expected Result**:
✅ Verification criteria
✅ Observable outcomes
✅ System state validation

---

Test Case Design Principles

1. Test Case ID Convention

TC-[CATEGORY]-[NUMBER]

Examples:
- TC-CLI-001 (CLI tests)
- TC-WEB-042 (Web tests)
- TC-API-103 (API tests)
- TC-SEC-007 (Security tests)

2. Priority Classification

P0 (Blocker) - Must fix before release

• Prevents core functionality
• Security vulnerabilities (SQL injection, XSS)
• Data corruption/loss
• System crashes

P1 (Critical) - Fix within 2 weeks

• Major feature broken with workaround
• Significant UX degradation
• Performance issues

P2 (High) - Fix within 4 weeks

• Minor feature issues
• Edge cases
• Non-critical bugs

P3 (Medium) - Fix when possible

• Cosmetic issues
• Rare edge cases
• Nice-to-have improvements

P4 (Low) - Optional

• Documentation typos
• Minor UI alignment

3. Test Types

Unit Tests:

• Test individual functions/methods
• No external dependencies
• Fast execution (<100ms)
• Coverage: ≥80% statements, 75% branches

Integration Tests:

• Test component interactions
• Real dependencies (database, APIs)
• Moderate execution time
• Coverage: Critical user journeys

E2E Tests:

• Test complete user workflows
• Real browser/environment
• Slow execution
• Coverage: Happy paths + critical failures

Security Tests:

• OWASP Top 10 coverage
• Input validation
• Authentication/authorization
• Data protection

---

Coverage Thresholds

Code Coverage Targets

• ✅ Statements: ≥80%
• ✅ Branches: ≥75%
• ✅ Functions: ≥85%
• ✅ Lines: ≥80%

Test Distribution (Recommended)

• Unit Tests: 70%
• Integration Tests: 20%
• E2E Tests: 10%

---

Test Isolation

Mandatory Principles

1. No Shared State

   ❌ BAD: Tests share global variables
   ✅ GOOD: Each test has independent data
   

2. Fresh Data Per Test

   beforeEach(() => {
     database.seed(freshData);
   });
   

3. Cleanup After Tests

   afterEach(() => {
     database.cleanup();
     mockServer.reset();
   });
   

---

Fail-Fast Validation

Critical Security Pattern

// ❌ BAD: Fallback to mock data
if (error) {
  return getMockData(); // WRONG - hides issues
}

// ✅ GOOD: Fail immediately
if (error || !data) {
  throw new Error(error?.message || 'Operation failed');
}

Input Validation

// Validate BEFORE any operations
function processSkillName(input: string): void {
  // Security checks first
  if (input.includes('..')) {
    throw new ValidationError('Path traversal detected');
  }

  if (input.startsWith('/')) {
    throw new ValidationError('Absolute paths not allowed');
  }

  // Then business logic
  return performOperation(input);
}

---

Test Documentation Standards

Test Case Template

### TC-XXX-YYY: Descriptive Title

**Priority**: P0/P1/P2/P3/P4
**Type**: Unit/Integration/E2E/Security
**Estimated Time**: X minutes

**Prerequisites**:
- Specific, verifiable conditions

**Test Steps**:
1. Exact command or action
2. Specific input data
3. Verification step

**Expected Result**:
✅ Measurable outcome
✅ Specific verification criteria

**Pass/Fail Criteria**:
- ✅ PASS: All verification steps succeed
- ❌ FAIL: Any error or deviation

**Potential Bugs**:
- Known edge cases
- Security concerns

---

Quality Gates

Release Criteria

Gate	Threshold	Blocker
Test Execution	100%	Yes
Pass Rate	≥80%	Yes
P0 Bugs	0	Yes
P1 Bugs	≤5	Yes
Code Coverage	≥80%	Yes
Security	90% OWASP	Yes

Daily Checkpoints

Morning Standup:

• Yesterday's progress
• Today's plan
• Blockers

End-of-Day:

• Tests executed
• Pass rate
• Bugs filed
• Tomorrow's plan

Weekly Review

Friday Report:

• Week summary
• Baseline comparison
• Quality gates status
• Next week plan

---

Best Practices Summary

DO:

• ✅ Write reproducible test cases
• ✅ Update tracking after EACH test
• ✅ File bugs immediately on failure
• ✅ Follow AAA pattern
• ✅ Maintain test isolation
• ✅ Document environment details

DON'T:

• ❌ Skip test documentation
• ❌ Batch CSV updates
• ❌ Ignore security tests
• ❌ Use production data in tests
• ❌ Skip cleanup
• ❌ Hard-code test data

---

References:

• Google Testing Blog
• Google SWE Book - Testing
• Test Pyramid Concept