Add Unit and Integration Tests for Core Modules

The project currently lacks sufficient test coverage, which increases the risk of introducing bugs and makes it harder to ensure the stability of the system. Unit and integration tests should be added to validate the functionality of core modules and ensure that future changes do not break existing features.

#### Proposed Solution:
1. **Identify Core Modules**:
- Focus on critical modules such as:
- `config` (configuration management)
- `chat` (chat agent logic)
- `service` (service interface)
- `context` (context management)

2. **Write Unit Tests**:
- Test individual functions and classes in isolation.
- Mock dependencies where necessary to ensure tests are focused and reliable.

3. **Write Integration Tests**:
- Test interactions between modules to ensure they work together as expected.
- Include end-to-end tests for key workflows, such as initializing the chat agent and processing a user query.

4. **Set Up Test Framework**:
- Use a testing framework like `pytest` for writing and running tests.
- Add a test coverage tool (e.g., `pytest-cov`) to measure and improve coverage.

5. **Automate Testing**:
- Integrate tests into the CI/CD pipeline to ensure they run automatically on every commit.

#### Benefits:
- Improved code quality and reliability.
- Easier detection of bugs and regressions.
- Increased confidence in making changes to the codebase.

#### Tasks:
- [ ] Set up the tests directory structure.
- [ ] Write unit tests for the `config` module.
- [ ] Write unit tests for the `chat` module.
- [ ] Write integration tests for the `service` module.
- [ ] Add test coverage reporting.
- [ ] Update documentation to include testing instructions.

#### References:
- [`pytest`](https://docs.pytest.org/)
- [`pytest-cov`](https://pytest-cov.readthedocs.io/)

#### Priority:
Medium

#### Additional Notes:
Ensure that tests are written for both expected behavior and edge cases. Mock external dependencies (e.g., APIs or databases) to avoid flaky tests.