feat: Set up Python testing infrastructure with Poetry and pytest

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a complete testing infrastructure for the XXMI Launcher project, migrating from traditional requirements.txt to modern Poetry package management and setting up pytest as the testing framework.

Changes Made

Package Management

• Created pyproject.toml with Poetry configuration
• Migrated all 27 dependencies from requirements.txt to Poetry
• Properly marked Windows-specific dependencies (pywin32, WMI, winshell)
• Added development dependencies for testing

Testing Framework

• pytest - Main testing framework with comprehensive configuration
• pytest-cov - Coverage reporting with HTML and XML output formats
• pytest-mock - Mocking utilities for unit tests

Project Structure

tests/
├── __init__.py
├── conftest.py          # Shared pytest fixtures
├── test_infrastructure_validation.py  # Validation tests
├── unit/               # Unit tests directory
│   └── __init__.py
└── integration/        # Integration tests directory
    └── __init__.py

Testing Configuration (pyproject.toml)

• Test discovery patterns for flexible naming conventions
• Coverage settings with reports in multiple formats
• Custom test markers: @pytest.mark.unit, @pytest.mark.integration, @pytest.mark.slow
• Strict mode enabled for better error detection
• Coverage threshold set to 0% temporarily (with TODO to increase to 80%)

Shared Fixtures (conftest.py)

• temp_dir - Temporary directory management
• mock_config_dir - Mock configuration directory
• mock_app_config - Application configuration mocks
• mock_game_info - Game information mocks
• mock_mod_info - Mod information mocks
• mock_requests_get - Network request mocking
• mock_subprocess - Subprocess execution mocking
• mock_logger - Logger mocking
• mock_window - GUI window mocking
• clean_environment - Environment variable isolation
• mock_platform_system - Platform detection mocking

Development Commands

# Install dependencies
poetry install

# Run all tests
poetry run test
# or
poetry run tests

# Run tests with specific markers
poetry run pytest -m unit
poetry run pytest -m integration

# Run with verbose output
poetry run pytest -v

# Run specific test file
poetry run pytest tests/test_infrastructure_validation.py

Updated .gitignore

Added entries for:

• Testing artifacts (.pytest_cache/, .coverage, htmlcov/, etc.)
• Poetry artifacts (dist/, *.egg-info/)
• Virtual environments
• IDE files
• Claude settings (.claude/*)

Testing the Infrastructure

The validation test suite (test_infrastructure_validation.py) verifies:

• Python path configuration
• Project structure existence
• Fixture availability and functionality
• Test markers working correctly
• Import capabilities

All 12 validation tests pass successfully, confirming the infrastructure is properly configured.

Next Steps

1. Developers can now write unit tests in tests/unit/
2. Integration tests go in tests/integration/
3. Coverage threshold should be increased from 0% to 80% as tests are added
4. The TODO comments in pyproject.toml indicate where to update the coverage threshold

Notes

• Poetry lock file (poetry.lock) is intentionally not gitignored and should be committed
• Coverage reports show 0% because no actual unit tests for the codebase were written (only infrastructure validation)
• Some Python files couldn't be parsed by coverage due to syntax specific to newer Python versions, but this doesn't affect the testing infrastructure
• The project uses Windows-specific dependencies which are properly marked with platform markers