Add test coverage for the global error handler, 413 payload limit, and 404 fallback

[mikewheeleer]

Test the error handler, payload limit, and 404 fallback

Description

The final error handler in src/index.ts special-cases entity.too.large into a 413 payload_too_large and otherwise returns a uniform 500 internal_error; the unknown-route middleware returns a structured 404. Only the 404 case is tested in src/health.test.ts. This issue covers the error and limit paths.

Requirements and context

• Repository scope: Agentpay-Org/Agentpay-backend only.
• Test that a body exceeding the 100 KiB express.json limit returns 413 payload_too_large with a requestId.
• Test malformed JSON bodies are handled with a structured error (verify the actual status/shape produced).
• Test the unknown-route 404 not_found echoes method + path and a requestId.
• Assert every error response includes error, message, and requestId keys consistently.

Suggested execution

• Fork the repo and create a branch
• git checkout -b test/testing-17-error-handler
• Implement changes
  • Write comprehensive tests in: new src/errors.test.ts using supertest (send an oversized/malformed body).
  • Write code in: if malformed-JSON handling is inconsistent, fix it and document the change.
  • Add documentation: none beyond test descriptions.
  • Add clear test titles.
  • Validate security assumptions: error messages do not leak stack traces or internal paths.
• Test and commit

Test and commit

• Run npm run build, npm test, and npm run lint.
• Cover edge cases: oversized body, invalid JSON, unknown route for several methods.
• Include the full npm test output in the PR description.

Example commit message

test: cover error handler, payload limit, and 404 fallback

Guidelines

• Minimum 95 percent test coverage for impacted modules.
• Clear, reviewer-focused documentation.
• Timeframe: 96 hours.

Community & contribution rewards

• 💬 Join the AgentPay community on Discord for questions, reviews, and faster merges: https://discord.gg/eXvRKkgcv
• ⭐ This is a GrantFox OSS / Official Campaign task and may be rewarded. When your PR is merged you'll be prompted to rate the project — if this issue and the maintainers helped you ship, we'd be grateful for a 5-star rating. Clear questions in Discord and tidy, well-tested PRs are the fastest path to a merge and a reward.

[BojayL]

/claim

[BojayL]

/attempt #70

[gloskull]

Hello, I have 4 years of experience delivering solutions for projects like this, covering backend, frontend, and smart contract development. After carefully reviewing your requirements, I have a clear understanding of the task and am confident in my ability to deliver a clean, efficient, and thoroughly tested solution on time. I prioritize code quality, maintainability, and industry best practices throughout the development process. My PR will be submitted in under 10hours.

[pq198363-ops]

/claim