Description

Develop stricter invoice upload checks for verified businesses, amount boundaries, due dates, and list indexes.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Prevent invalid invoice state insertion into indexes

Suggested execution

• Fork the repo and create a branch
• git checkout -b feature/invoice-upload-hardening
• Implement changes
• Write contract: src/invoice.rs and src/lib.rs
• Write comprehensive tests: src/test_invoice.rs and src/test_lifecycle.rs
• Add documentation: docs/contracts/invoice.md
• Include NatSpec-style comments
• Validate security assumptions

Test and commit

• Run tests
• Cover edge cases
• Include test output and security notes

Example commit message

feat: harden invoice upload validation and indexing

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours