Unit Tests for AuthService

[Josue19-08]

🔖 Title

Unit Tests for AuthService

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📄 Description

Write comprehensive unit tests for the AuthService covering nonce generation, signature verification, and JWT token issuance. Mock all external dependencies including Supabase client and Stellar SDK. This issue can be completed independently once issues #49 and #50 are implemented.

Related to: Meta-issue #67

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✅ Tasks to complete

• Test nonce generation produces unique cryptographic nonces
• Test nonce storage in database with correct TTL
• Test signature verification with valid Stellar Ed25519 signatures
• Test signature verification rejects invalid signatures
• Test JWT access token generation with correct payload and expiry
• Test JWT refresh token generation and storage
• Test error handling for expired nonces
• Test error handling for already-used nonces
• Mock Supabase client for all database operations
• Mock Stellar SDK for signature verification
• Achieve 80%+ coverage for AuthService

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📚 Documentation/context for AI

(This link never should removed)
https://github.com/TrustUp-app/TrustUp-API/tree/main/docs

Relevant documentation:

• https://github.com/TrustUp-app/TrustUp-API/blob/main/docs/development/testing-structure.md
• https://github.com/TrustUp-app/TrustUp-API/blob/main/docs/development/services-structure.md

Dependencies:

• Issue Complete JWT Authentication Guard Implementation #49 (JWT Guard) should be implemented
• Issue User Registration Endpoint with Profile Image Upload #50 (Registration) should be implemented

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🗒️ Additional notes

Acceptance Criteria:

• All test cases pass
• Code coverage for AuthService is at least 80%
• All external dependencies are mocked
• Tests run in isolation without database or network calls
• Edge cases are covered (null inputs, invalid formats, expired data)