Add security-focused test cases

[ISTIFANUS-N]

Description

Security-focused test cases are missing.

Acceptance Criteria

• Test access control
• Validate input sanitization
• Test reentrancy protection
• Check overflow protection

[nanaf6203-bit]

@nanaf6203-bit has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Can i take this please

ℹ️ Repo Maintainers: To accept this application, review their application or assign @nanaf6203-bit to this issue.

[drips-wave]

Congratulations, @nanaf6203-bit! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

🧑‍💻 @nanaf6203-bit: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

This issue has been completed by @nanaf6203-bit as part of the Stellar Wave Program's 4th Wave 🥳

😎 @nanaf6203-bit: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.