feat: Set up comprehensive Python testing infrastructure

[llbbl]

Set up comprehensive Python testing infrastructure

Summary

This PR establishes a complete testing infrastructure for the SciGLM project, providing a robust foundation for test-driven development and quality assurance.

🔧 Infrastructure Components Added

• Poetry Package Manager: Configured with pyproject.toml including proper Python version constraints for Streamlit compatibility
• Testing Framework: pytest with comprehensive configuration including coverage, markers, and strict options
• Coverage Reporting: 80% coverage threshold with HTML and XML report generation
• Testing Dependencies: pytest, pytest-cov, pytest-mock added to development group
• Directory Structure: Organized testing hierarchy with unit and integration test separation

📁 Files Created/Modified

• pyproject.toml - New Poetry configuration with dependencies and testing setup
• tests/ directory structure with proper __init__.py files
• tests/conftest.py - Comprehensive shared fixtures for common testing scenarios
• tests/test_infrastructure.py - Validation test suite to verify setup functionality
• .gitignore - Updated with Claude Code entries

🧪 Testing Features

• Custom Test Markers: unit, integration, and slow markers for selective test execution
• Shared Fixtures: Common testing utilities including temp directories, mock configurations, sample data
• Coverage Configuration: Source tracking with appropriate exclusions and detailed reporting
• Environment Management: Automatic cleanup and warning suppression for cleaner test output

🚀 Usage Instructions

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 "not slow"    # Exclude slow tests

# Run with verbose output
poetry run pytest -v

# Generate coverage reports
poetry run pytest --cov-report=html

Test Organization

• tests/unit/ - Unit tests for individual components
• tests/integration/ - Integration tests for component interactions
• tests/conftest.py - Shared fixtures and configuration
• Mark tests with @pytest.mark.unit, @pytest.mark.integration, or @pytest.mark.slow

📊 Configuration Details

• Python Version: Configured for >=3.9,<3.9.7 || >3.9.7,<4.0 (Streamlit compatibility)
• Coverage Threshold: 80% minimum coverage required
• Test Discovery: Automatic discovery of test_*.py and *_test.py files
• Reporting: Terminal, HTML (htmlcov/), and XML (coverage.xml) formats

✅ Validation

The infrastructure has been validated with:

• 13 passing infrastructure tests covering all major components
• Successful dependency installation and resolution
• Working test markers and fixture system
• Coverage reporting functionality
• Environment cleanup and isolation

📝 Notes

• The existing requirements.txt dependencies have been migrated to Poetry format
• Poetry lock file is intentionally not in .gitignore for reproducible builds
• Infrastructure is ready for immediate use - no additional setup required
• Comprehensive fixtures in conftest.py provide common testing utilities

This setup provides a solid foundation for test-driven development and ensures code quality through automated testing and coverage reporting.