Implement E2E tests - Githubissues

Currently, tests are implemented only for the service layer. It would be beneficial to implement E2E tests as well.

Benefits of the feature

User Perspective: Ensures that the API and all connected components function correctly from the user's point of view.
Comprehensive Coverage: Tests the full workflow, including interactions between different application layers.
Early Detection: Catches issues early in the development process, reducing the risk of defects in production.
Documentation: Provides executable documentation of how the entire application is expected to work.
Confidence: Increases confidence in the stability of the application, especially when making changes or adding new features.