feat: Set up Python testing infrastructure with Poetry

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a complete Python testing infrastructure for the project using Poetry as the package manager and pytest as the testing framework.

Changes Made

• Package Management: Added pyproject.toml with Poetry configuration set to package-mode disabled (appropriate for non-Python package projects)
• Testing Dependencies: Installed core testing packages as development dependencies:
  • pytest (v7.4.0+) - Main testing framework
  • pytest-cov (v4.1.0+) - Coverage reporting
  • pytest-mock (v3.11.1+) - Mocking utilities
• Testing Configuration: Comprehensive pytest and coverage settings including:
  • Test discovery patterns
  • Coverage thresholds and reporting formats (HTML, XML, terminal)
  • Custom markers for unit, integration, and slow tests
  • Strict options and warning filters
• Directory Structure: Created proper testing hierarchy:

  tests/
  ├── __init__.py
  ├── conftest.py
  ├── test_infrastructure.py
  ├── unit/
  │   └── __init__.py
  └── integration/
      └── __init__.py
  

• Shared Fixtures: Added comprehensive fixtures in conftest.py:
  • temp_dir and temp_file for file system testing
  • mock_env_vars for environment variable mocking
  • sample_config, sample_yaml_content, sample_json_content for test data
  • Project structure helpers (project_root, charts_dir, manifests_dir)
• Validation Tests: Created test_infrastructure.py to verify the setup works correctly
• Development Scripts: Poetry commands for running tests (poetry run pytest)
• .gitignore Updates: Added testing artifacts, build files, and Claude Code entries

Testing Infrastructure Components

Running Tests

# Install dependencies
poetry install

# Run all tests
poetry run pytest

# Run with coverage
poetry run pytest --cov

# Run specific test types
poetry run pytest -m unit
poetry run pytest -m integration
poetry run pytest -m slow

# Run tests in specific directories
poetry run pytest tests/unit/
poetry run pytest tests/integration/

Coverage Reporting

• Terminal output with missing line indicators
• HTML report generated in htmlcov/
• XML report for CI/CD integration (coverage.xml)
• Configurable coverage thresholds (currently set to 0% for initial setup)

Custom Test Markers

• @pytest.mark.unit - Unit tests
• @pytest.mark.integration - Integration tests
• @pytest.mark.slow - Long-running tests

Validation

✅ All validation tests pass (14/14)
✅ Poetry dependencies install successfully
✅ pytest configuration loads without errors
✅ Coverage reporting generates properly
✅ Project structure fixtures work correctly
✅ Custom markers are recognized

Next Steps

Developers can now immediately start writing tests using the established infrastructure:

1. Unit Tests: Add to tests/unit/ directory
2. Integration Tests: Add to tests/integration/ directory
3. Shared Test Utilities: Add to tests/conftest.py
4. Adjust Coverage Thresholds: Update --cov-fail-under in pyproject.toml as codebase grows

The infrastructure is ready for immediate use with comprehensive fixtures, proper configuration, and validation that ensures everything works correctly.