feat: Add comprehensive Python testing infrastructure with Poetry

[llbbl]

Add Python Testing Infrastructure

Summary

This PR sets up a comprehensive testing infrastructure for the MSDAT project using Poetry as the package manager and pytest as the testing framework. The setup provides a solid foundation for writing and running tests with coverage reporting.

Changes Made

Package Management

• Poetry Setup: Added pyproject.toml with Poetry configuration
• Dependency Migration: Migrated all dependencies from requirements.txt to Poetry
• Development Dependencies: Added pytest, pytest-cov, and pytest-mock as dev dependencies

Testing Configuration

• pytest Configuration:

  • Configured test discovery patterns
  • Added custom markers (unit, integration, slow)
  • Set up coverage reporting with HTML and XML outputs
  • Enabled strict markers and configuration

• Coverage Configuration:

  • Source directory coverage tracking
  • Excluded test files, cache directories, and virtual environments
  • Configured coverage report formats and exclusion patterns

Directory Structure

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

Shared Fixtures (conftest.py)

Created comprehensive fixtures for common testing needs:

• temp_dir - Temporary directory management
• temp_file - Temporary file creation
• mock_config - Mock configuration dictionary
• mock_database_connection - Mock database connection and cursor
• mock_argparse_args - Mock command line arguments
• mock_logger - Mock logger object
• sample_sql_results - Sample SQL query results
• mock_file_system - Mock file system structure
• mock_network_response - Mock network responses
• reset_modules - Module reset between tests
• capture_output - Stdout/stderr capture
• mock_progressbar - Mock progress bar
• environment_variables - Temporary environment variable management
• mock_color_output - Mock colored terminal output

Other Updates

• gitignore: Updated with testing artifacts (.pytest_cache/, coverage files) and Claude settings
• Poetry Scripts: Added poetry run test and poetry run tests commands

How to Use

1. Install dependencies:

   poetry install

2. Run all tests:

   poetry run test
   # or
   poetry run tests

3. Run specific test files:

   poetry run pytest tests/test_setup_validation.py

4. Run tests with specific 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

5. View coverage report:

   • HTML report: Open htmlcov/index.html in a browser
   • XML report: Available at coverage.xml

Notes

• The testing infrastructure is ready to use - developers can immediately start writing tests
• Coverage threshold is currently not enforced to allow gradual test adoption
• The argparse package was removed from dependencies as it conflicts with pytest (argparse is built-in to Python 3)
• All pytest options are available when using the poetry run test/tests commands

Validation

The setup has been validated with a comprehensive test file (test_setup_validation.py) that verifies:

• All testing dependencies are properly installed
• All fixtures are working correctly
• Test markers are configured
• Coverage reporting is functional