feat: Set up comprehensive Python testing infrastructure with Poetry

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the batch-ppo project using Poetry as the package manager and pytest as the testing framework. The setup provides a solid foundation for writing and maintaining tests with proper coverage reporting and development tooling.

Changes Made

Package Management

• ✅ Added Poetry configuration in pyproject.toml
• ✅ Migrated existing dependencies from setup.py
• ✅ Added development dependencies for testing

Testing Configuration

• ✅ Configured pytest with:
  • Test discovery patterns for test_*.py and *_test.py
  • Coverage reporting with 80% threshold
  • HTML and XML coverage output formats
  • Custom test markers: @pytest.mark.unit, @pytest.mark.integration, @pytest.mark.slow
  • Strict marker enforcement

Directory Structure

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

Shared Fixtures (in conftest.py)

• temp_dir: Temporary directory with automatic cleanup
• mock_config: Sample configuration dictionary
• mock_config_file: Temporary YAML config file
• tf_session: TensorFlow session management
• mock_environment: Mock Gym environment
• sample_trajectory: Sample training data
• cleanup_tensorflow: Automatic TF state cleanup
• capture_stdout: Stdout capture for testing print statements

Development Commands

Both commands are configured to run the test suite:

• poetry run test
• poetry run tests

Additional Updates

• Updated .gitignore with:
  • Testing artifacts (.pytest_cache/, .coverage, htmlcov/, etc.)
  • Claude settings (.claude/*)
  • Virtual environments and IDE files
  • Note: poetry.lock is NOT ignored (should be committed)

How to Use

1. Install Poetry (if not already installed):

   curl -sSL https://install.python-poetry.org | python3 -

2. Install dependencies:

   poetry install

3. Run tests:

   poetry run test
   # or
   poetry run tests

4. Run specific test categories:

   # Unit tests only
   poetry run pytest -m unit
   
   # Integration tests only
   poetry run pytest -m integration
   
   # Exclude slow tests
   poetry run pytest -m "not slow"

5. View coverage report:

   • Terminal: Automatically shown after test run
   • HTML: Open htmlcov/index.html in browser
   • XML: Available at coverage.xml for CI integration

Notes

• The validation test suite confirms all infrastructure components are working correctly
• Coverage threshold is set to 80% - tests will fail if coverage drops below this
• The codebase has TensorFlow 1.x compatibility issues that need to be addressed separately
• All pytest options remain available (e.g., -v for verbose, -x to stop on first failure)

Next Steps

With this infrastructure in place, developers can now:

1. Write unit tests in tests/unit/
2. Write integration tests in tests/integration/
3. Use the provided fixtures for common testing needs
4. Monitor test coverage to maintain code quality