Python Unit Testing with pytest

Create unit tests for my Python code:

```python
[PASTE YOUR CODE TO TEST]
```

Testing requirements:
- Test framework: pytest
- Coverage target: [80%/90%/100%]
- Mock external services: [YES/NO]
- Integration tests needed: [YES/NO]

Provide:
1. Test file structure
2. pytest.ini configuration
3. Fixtures for common setup
4. Parametrized tests
5. Mocking with pytest-mock
6. Testing exceptions
7. Testing async code
8. Test markers and categories
9. Coverage configuration
10. CI integration
11. Test data management
12. Property-based testing (hypothesis)