[Test] Add unit, integration, and e2e tests for existing features

[marcomoi395]

Objective:

Add unit, integration, and e2e test coverage for the current features.

To-do:

• Identify current features lacking tests
• Implement unit tests for core logic
• Implement integration tests for interacting modules
• Implement e2e tests for end-to-end flows
• Ensure tests run reliably in CI and update documentation/scripts if needed