[contract] Write comprehensive unit tests for core contract logic (Part 2)

[starTecchie]

Description

Implement and refine the following task: Write comprehensive unit tests for core contract logic within the contract environment.

Requirements and context

• Code must follow project guidelines and existing design patterns.
• Ensure all edge cases are considered.
• Refer to the issueTemplate.md for quality standards.

Suggested execution

1. Fork the repo and create a branch feature/test-task-30
2. Implement the necessary code changes in the contract directory.
3. Write associated tests to prove your solution works.
4. Document any new functions or architecture changes.

Guidelines

• Assignment required before starting.
• Complexity Level: Medium (150 points)

[Emelie-Dev]

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

Hi, I would love to work on this issue

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

[nursetechie]

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

Good day maintainer, I would love to jump on this Asap

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

[wavyboy-build]

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

Please assign me this issue

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

[drips-wave]

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

🧑‍💻 @nursetechie: 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 🌊