Frontend PR-3: Integration Tests & Developer Documentation (Closes Epic)

[kevalyq]

📦 Sub-Issue of Epic #208

Part of: #208 (httpOnly Cookie Authentication Migration)
Priority: High
Area: Frontend, Testing, Documentation
Repository: frontend

Goal

Add comprehensive integration tests for the complete httpOnly cookie authentication flow and create developer documentation for the new authentication mechanism.

Acceptance Criteria

• Integration tests for login flow with cookies
• Integration tests for CSRF token handling
• Integration tests for authenticated requests
• Integration tests for logout flow
• Integration tests for CSRF token refresh (419 retry)
• Tests verify no token in localStorage
• Tests verify cookies sent with requests
• Developer migration guide documented
• Code coverage ≥80% for new code
• TypeScript strict mode passes
• ESLint passes
• All tests pass

Implementation Details

New test files:

• tests/integration/auth/cookieAuth.test.ts
• tests/integration/auth/csrfProtection.test.ts

Test scenarios:

1. Login flow with CSRF token fetch
2. Authenticated request with cookies
3. Request without cookies fails (401)
4. CSRF token included in POST/PUT/PATCH/DELETE
5. 419 response triggers CSRF refresh and retry
6. Logout clears session
7. No token accessible via JavaScript
8. Cookies have correct attributes in dev tools

Documentation updates:

• Create docs/authentication-migration.md
• Update README.md with new auth flow
• Add migration guide in CHANGELOG.md
• Update developer setup guide

Migration Guide Content:

• Overview of changes (localStorage → httpOnly cookies)
• Security benefits
• Local development setup
• API changes for developers
• Troubleshooting common issues

Dependencies

• Depends on: Frontend PR-1, Frontend PR-2 (implementation must be complete)
• Blocks: None (closes Epic [EPIC] Security: Migrate authentication from localStorage to httpOnly cookies #208)

Testing

npm test -- --coverage
npm run typecheck
npm run lint
npm run build

References

• React Testing Library
• Vitest
• Epic: [EPIC] Security: Migrate authentication from localStorage to httpOnly cookies #208 (this PR closes the epic with Closes #208)

[github-actions]

✅ This issue has been added to the SecPal Feature Roadmap with status: 💡 Ideas

New idea - needs discussion and evaluation

Status Flow:
💡 Ideas → 💬 Discussion → 📥 Backlog → 📋 Planned → 🚧 In Progress → 👀 In Review → ✅ Done

Note: Ideas that won't be implemented should be moved to 🚫 Won't Do with a reason.