feat: Set up Python testing infrastructure with Poetry and pytest

[llbbl]

Add Python Testing Infrastructure

Summary

This PR sets up a comprehensive testing infrastructure for the reinforcement learning project using Poetry and pytest. The setup provides a solid foundation for writing unit and integration tests, with proper coverage reporting and modern Python tooling.

Changes Made

Package Management

• ✅ Configured Poetry as the package manager
• ✅ Created pyproject.toml with project metadata and dependencies
• ✅ Added testing dependencies as development dependencies

Testing Framework

• ✅ Added pytest as the primary testing framework
• ✅ Added pytest-cov for coverage reporting
• ✅ Added pytest-mock for mocking utilities

Configuration

• ✅ Comprehensive pytest configuration in pyproject.toml:
  • Test discovery patterns
  • Coverage settings with HTML and XML reports
  • Custom test markers (unit, integration, slow)
  • Strict mode for better error detection

Directory Structure

tests/
├── __init__.py
├── conftest.py          # Shared fixtures
├── test_setup_validation.py  # Validation tests
├── unit/
│   └── __init__.py
└── integration/
    └── __init__.py

Shared Fixtures

Created comprehensive fixtures in conftest.py:

• project_root - Project root directory path
• temp_dir - Temporary directory with automatic cleanup
• mock_config - Mock configuration for testing
• sample_game_state - Sample game state data
• mock_network - Mock neural network
• mock_env - Mock environment
• reset_random_seed - Automatic random seed reset
• capture_stdout - Stdout capture for testing print statements
• mock_model_save/load - Model persistence mocking

Developer Experience

• ✅ Poetry scripts configured: poetry run test or poetry run tests
• ✅ All standard pytest options available
• ✅ Coverage reports generated in multiple formats

Version Control

• ✅ Updated .gitignore with:
  • Python artifacts (__pycache__, *.pyc, etc.)
  • Testing artifacts (.pytest_cache, .coverage, htmlcov/)
  • Virtual environments
  • IDE files
  • Claude settings (.claude/*)

How to Use

1. Install dependencies:

   poetry install

2. Run all tests:

   poetry run test
   # or
   poetry run tests

3. Run specific test markers:

   poetry run pytest -m unit        # Run only unit tests
   poetry run pytest -m integration # Run only integration tests
   poetry run pytest -m "not slow"  # Skip slow tests

4. Run with coverage report:

   poetry run pytest --cov

5. View HTML coverage report:

   open htmlcov/index.html

Notes

• Coverage threshold is currently set to 0% to allow initial development. This should be increased as tests are added.
• The infrastructure handles optional dependencies (numpy, torch, tensorflow) gracefully in fixtures.
• Validation tests are included to verify the setup works correctly.
• Poetry lock file (poetry.lock) is tracked in git for reproducible builds.

Next Steps

With this infrastructure in place, developers can now:

1. Write unit tests for individual components
2. Create integration tests for game logic
3. Add performance tests for training algorithms
4. Implement mocking strategies for external dependencies