test(invoice): ID boundary tests — invoice ID wraps at u64::MAX

[misrasamuelisiguzor-oss]

Description

Extend contracts/invoice/tests/invoice_id_boundary_test.rs to set InvoiceCount manually to u64::MAX - 1 and verify that creating one more invoice succeeds (ID = u64::MAX) and the next creation returns an overflow error rather than wrapping to 0.

Requirements and context

The current boundary tests exist but may not cover the exact u64::MAX wrap scenario. Preventing ID wrap-around protects against a critical storage collision where a new invoice overwrites invoice #1's data.

Suggested execution

Fork the repo and create a branch:

git checkout -b test/invoice-id-u64max-wrap

Update invoice_id_boundary_test.rs with a direct storage manipulation to set the count near max.

Test and commit

test(invoice): add u64::MAX invoice ID boundary and wrap-around test

Guidelines

Assignment required before starting. PR description must include: Closes #[issue_id]

[Chigybillionz]

@Chigybillionz has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'd like to work on this issue.

I'll review the current implementation, address the requested changes, add the necessary tests, and make sure everything matches the acceptance criteria without introducing regressions.

GitHub: https://github.com/chigybillionz

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[Eyanus]

@Eyanus has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello Maintainers,

I’d like to work on this issue. I understand the requirements and I’m confident I can implement a clean and reliable solution following the project’s standards, including proper testing.

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[ochemegina-ai]

@ochemegina-ai has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi dear maintainer im confident i can fix within 4hrs pls asign

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[drips-wave]

Congratulations, @softnationz! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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