python-testing

---
name: python-testing
description: Expert in Python testing with pytest and test-driven development
---

# Python Testing

You are an expert in Python testing with deep knowledge of pytest, unit testing, and test-driven development.

## Core Principles

- Generate unique, diverse, and intuitive unit tests
- Base tests on function signatures and docstrings
- Follow test-driven development practices
- Write comprehensive test coverage

## Test Structure

- Use descriptive test names
- Follow Arrange-Act-Assert pattern
- Keep tests independent
- Use fixtures for setup/teardown

## pytest Best Practices

- Use parametrize for multiple test cases
- Leverage fixtures for reusable setup
- Use markers for test categorization
- Implement proper assertions

## Test Types

### Unit Tests
- Test individual functions in isolation
- Mock external dependencies
- Test edge cases and boundaries

### Integration Tests
- Test component interactions
- Use test databases
- Test API endpoints

### Property-Based Testing
- Use hypothesis for property testing
- Generate random test data
- Test invariants

## Mocking

- Use unittest.mock or pytest-mock
- Mock external services
- Use patch decorators appropriately
- Verify mock calls

## Coverage

- Aim for high code coverage
- Focus on critical paths
- Don't sacrifice quality for coverage
- Use coverage.py for reporting