Add Testing Infrastructure and Test Coverage

## Problem
Currently, the repository does not include any tests or test configuration files. This makes it difficult to ensure code reliability, prevent regressions, and increase contributor confidence.

## Proposal
- Set up a testing framework (such as Vitest, Testing Library, or another appropriate tool).
- Add sample test cases to validate core functionality.
- Include configuration files and instructions for running tests.

## Benefits
- Improved reliability and maintainability of the codebase.
- Easier onboarding for contributors.
- Ability to catch bugs and regressions early.

## Additional Notes
Please discuss and suggest preferred testing frameworks, if any, for alignment with project goals.