Test/consolidate test suite

[ademboukabes]

Note

Context
This PR introduces a robust testing infrastructure to ensure the reliability of our core services. It adds extensive Unit, Integration, and End-to-End (E2E) tests tailored to the new asynchronous OTP authentication flow and the AI photo processing pipeline.

Test Coverage & Scope

1. Unit Tests (tests/unit/)

• Auth & Security: Validates the two-step mobile registration flow (OTP), login intent, JWT token validation, and rate-limiting limits.
• Photo Approval Service: Tests the decision-making lifecycle for photos (Approve/Reject/Pending) and verifies audit logging behaviors.
• AI Worker Messaging: Verifies that NATS messages for single faces and group photos are properly processed and that notifications are correctly dispatched.
• Data Privacy: Ensures strict GDPR compliance by confirming no plaintext emails or sensitive data leak into the server logs.

2. Integration Tests (tests/integration/)

• Database Interactions: Uses a real PostgreSQL database to verify that AI-generated face embeddings (vectors) are correctly persisted upon user enrollment without dimension errors.
• Flow state: Ensures that OTP sessions are successfully stored and cleaned up in Redis during the registration cycle.

3. End-to-End (E2E) Tests (tests/e2e/)

• Full Authentication Pipeline: Simulates a complete user journey: hitting the /register endpoint, retrieving the OTP directly from Redis, validating via /register/verify, and successfully logging in.
• AI Load & Edge Cases: Simulates real-world traffic by uploading multiple photos (empty photos, group photos, and massive batches of 20+ photos) to ensure the API and AI Worker can handle concurrent load without crashing.

Verification

All tests are passing successfully (140/140) across the entire suite.

• Unit tests passed locally
• Integration tests passed locally
• E2E tests passed locally