[CT-19] Write Access Control Test Suite (10+ tests) in Rust

[devwums]

Problem

The access_control contract functions have minimal test coverage. Role granting, revocation, and multi-role scenarios are entirely untested.

Proposed Solution

Create contracts/cntr/tests/access_control_tests.rs. Write at least 10 unit tests covering: grant role to new address, grant same role twice (idempotent — must not duplicate), grant two different roles to the same address, revoke existing role, revoke non-existent role (must not panic), check role for unknown address, get all roles for multi-role holder, has_role with empty registry. All implementation must live inside contracts/cntr/.

Acceptance Criteria

• File at contracts/cntr/tests/access_control_tests.rs
• At least 10 test functions with descriptive names
• Idempotent grant is explicitly tested (same role granted twice does not appear twice in results)
• Tests import and use role_checker.rs peer module
• All tests pass with cargo test

[Jujukoder]

@Jujukoder has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Good Morning Ser, I'm an experienced rust dev, and I can solve this issue. Please assign it to me.

Thank you as you grant my request.

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

[authenticeasy-sys]

@authenticeasy-sys has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

can i take this

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

[drips-wave]

Congratulations, @authenticeasy-sys! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @authenticeasy-sys: 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.

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