Implement Unit Tests for Core Components

**Description**
The project currently does not include unit tests, which are essential for ensuring code reliability and simplifying future development.

**Suggested Action**
Create unit tests for key components including:

- FastAPI endpoints: verify that API routes return the expected responses.
- Data processing functions: validate data handling and transformations.
- Integration points: ensure proper integration with Prometheus and Grafana.

**Benefit**
Adding unit tests will improve code quality, make debugging easier, and allow safer modifications in the future.