Write Unit Tests for backend

---

## Tasks
1. **Set Up Testing Framework:**
- Install and configure `pytest` and `pytest-flask` for testing the application.

2. **Write Unit Tests for Routes:**
- Test each endpoint for expected behavior (e.g., HTTP status codes, JSON response structure, query parameters, and path parameters).

3. **Test Dependencies:**
- Mock external dependencies (e.g., databases, third-party APIs) using `unittest.mock` or `pytest-mock`.

4. **Test Application Context:**
- Ensure proper testing of the Flask app context and configurations.

5. **Organize Tests:**
- Place test files in the `tests/` directory.
- Use meaningful test function names and group related tests into separate files.

6. **Document Test Instructions:**
- Update the project README or contributing guide with steps to run tests locally.

---

## Acceptance Criteria
- [ ] All routes have at least one unit test.
- [ ] External dependencies are mocked and tested effectively.
- [ ] Tests are structured, organized, and easy to maintain.
- [ ] All tests pass when executed using `pytest`.

---

## References
- [Flask Testing Documentation](https://flask.palletsprojects.com/en/latest/testing/)
- [pytest Documentation](https://docs.pytest.org/en/latest/)
- [pytest-flask Documentation](https://pytest-flask.readthedocs.io/en/latest/)