feat: Add comprehensive Python testing infrastructure

[llbbl]

Add Complete Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the Python project, providing all necessary tooling and configuration for developers to immediately start writing and running tests.

Key Components Added

• Package Management: Poetry configuration with pyproject.toml
• Testing Framework: pytest with coverage reporting and mocking capabilities
• Directory Structure: Organized test directories (tests/, tests/unit/, tests/integration/)
• Shared Fixtures: Common test utilities in conftest.py
• Configuration: Comprehensive pytest and coverage settings

Dependencies Added

• pytest ^7.4.0 - Main testing framework
• pytest-cov ^4.1.0 - Coverage reporting
• pytest-mock ^3.11.0 - Enhanced mocking utilities

Configuration Features

pytest Configuration

• Test Discovery: Automatic discovery of test files and functions
• Custom Markers: unit, integration, and slow test categorization
• Coverage: 80% minimum coverage threshold with HTML and XML reports
• Strict Mode: Enforces proper test configuration and markers

Coverage Configuration

• Source Tracking: Monitors all Python files except test files and build artifacts
• Multiple Report Formats: Terminal, HTML (htmlcov/), and XML (coverage.xml)
• Exclusions: Properly excludes test files, build artifacts, and common patterns

Directory Structure

tests/
├── __init__.py
├── conftest.py              # Shared fixtures and test utilities
├── unit/
│   └── __init__.py
├── integration/
│   └── __init__.py
└── test_infrastructure_validation.py  # Validation tests

Running Tests

# Install dependencies
poetry install

# Run all tests
poetry run pytest

# Run specific test types
poetry run pytest -m unit          # Unit tests only
poetry run pytest -m integration   # Integration tests only
poetry run pytest -m slow          # Slow tests only

# Run with specific coverage options
poetry run pytest --cov-fail-under=90  # Require 90% coverage

Shared Fixtures Available

The conftest.py provides ready-to-use fixtures for common testing scenarios:

• temp_dir - Temporary directory for file operations
• temp_file - Temporary file creation and cleanup
• mock_subprocess - Mock subprocess.run calls
• mock_git - Mock git command execution
• sample_config - Sample configuration data
• mock_file_operations - Mock file read/write operations
• mock_environment - Mock environment variables
• capture_output - Capture stdout/stderr
• mock_network - Mock network requests
• mock_logger - Mock logging functionality
• cleanup_test_files - Automatic test file cleanup

Validation

All infrastructure has been validated with comprehensive tests that verify:

• ✅ pytest functionality and configuration
• ✅ Custom markers working correctly
• ✅ All shared fixtures operational
• ✅ Coverage reporting functional
• ✅ Project structure properly set up
• ✅ Python version compatibility
• ✅ Mock and patching capabilities

Files Modified

• New: pyproject.toml - Poetry and pytest configuration
• New: tests/ directory structure with __init__.py files
• New: tests/conftest.py - Comprehensive shared fixtures
• New: tests/test_infrastructure_validation.py - Infrastructure validation
• Modified: .gitignore - Added Python and testing exclusions

Next Steps

Developers can now:

1. Write unit tests in tests/unit/
2. Write integration tests in tests/integration/
3. Use any of the pre-configured fixtures from conftest.py
4. Run tests with poetry run pytest
5. Generate coverage reports automatically
6. Use custom markers to categorize and filter tests

The infrastructure is ready for immediate use and follows Python testing best practices.