Write integration tests for reward calculation endpoints

[AbdulSnk]

Overview

The StreamForge API needs integration tests to ensure reward calculation endpoints behave correctly end-to-end before any payout logic is triggered on the Stellar blockchain.

What needs to be done

• Set up a testing environment using NestJS testing utilities
• Write integration tests for the following scenarios:
  • Valid contributor with calculated rewards returns correct payout amount
  • Contributor with zero score returns zero reward
  • Missing or invalid contributor ID returns proper error
  • Unauthorized request returns 401
• Place all test files under the existing test/ directory
• Use supertest for HTTP-level integration testing

Acceptance Criteria

• At least 4 integration tests covering the scenarios above
• Tests live under test/ directory
• All tests pass with npm run test:e2e
• No hardcoded values — use test fixtures or factories
• CI pipeline runs these tests automatically on every PR

Notes

This is critical before connecting real Stellar payout logic. A broken reward calculation that reaches the blockchain cannot be reversed. Test coverage here protects contributors from incorrect payouts.