Validate invoice paid-state transitions from cumulative partial payments

[Baskarayelu]

Description

Develop cumulative partial payment tests validating exact transition to paid status at threshold amount.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Prevent early or delayed paid transitions

Suggested execution

• Fork the repo and create a branch
• git checkout -b feature/cumulative-partial-paid-transition
• Implement changes
• Write contract: src/settlement.rs and src/invoice.rs
• Write comprehensive tests: src/test_partial_payments.rs and src/test_settlement.rs
• Add documentation: docs/contracts/settlement.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: validate paid transitions from cumulative partial payments

Guidelines

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

[Eniola3321]

please can i work on the issue

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[EmmyKay0026]

@EmmyKay0026 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hi, I’d like to take this on. Implementing cumulative partial payment tests to validate exact transitions to paid status will help prevent premature or delayed state changes, improving reliability and correctness in payment handling. It also strengthens confidence in edge-case scenarios around thresholds. Please let me know if I can proceed or if there are any guidelines to follow. Thanks!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @EmmyKay0026 to this issue.

[Properprogress1]

@Properprogress1 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hey maintainer

I'd like to take on the cumulative partial payment validation task for QuickLendX.

Right now, there's no reliable guarantee that an invoice moves to "Paid" at exactly the right moment — not too early, not too late. For a lending protocol, that's a real trust problem. A borrower who underpays shouldn't be able to claim settlement, and a borrower who has fully paid shouldn't stay marked as in arrears.

I'll fix that by building solid settlement logic that tracks running payment totals and triggers the state change at precisely the right threshold — with no edge cases left open.

My deliverable will be clean, well-structured code across the relevant contract files, a thorough test suite covering normal flows and tricky edge cases, and clear documentation that makes the logic easy to follow for anyone reviewing or auditing the codebase. I'm targeting 95%+ test coverage as required.

The PR will be self-contained and ready to merge — no loose ends, no open questions for maintainers to chase down. If there's feedback, I'll turn it around within 24 hours.

Looking forward to contributing to the protocol. Let me know if you have any questions before I get started.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Properprogress1 to this issue.

[fairbid01]

@fairbid01 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

I would like to work on this issue. My plan:

Implement logic to track cumulative partial payments and enforce correct paid-state transitions
Write comprehensive tests covering threshold accuracy, edge cases, and invalid transitions
Add documentation with NatSpec-style comments and validate security assumptions

Tests will confirm that invoices transition to paid only when the exact threshold is reached, prevent early or delayed transitions, and ensure no regressions in settlement and payment flows.

Branch: feature/cumulative-partial-paid-transition
Commit: feat validate paid transitions from cumulative partial payments
PR will include: Closes issue #618, ready within the 96 hours.

Please assign, happy to start immediately.

Thanks!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @fairbid01 to this issue.