feat: Set up comprehensive Python testing infrastructure

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the Flask-based tarot webapp, providing developers with a robust foundation for writing and running tests.

Changes Made

Package Management

• Added Poetry as the package manager with pyproject.toml configuration
• Migrated dependencies from requirements.txt to Poetry format
• Maintained existing Flask 2.2.5 and gunicorn dependencies

Testing Framework

• Added pytest as the primary testing framework
• Added pytest-cov for coverage reporting with 80% threshold
• Added pytest-mock for enhanced mocking capabilities
• All testing dependencies added as development dependencies

Testing Configuration

• Comprehensive pytest configuration in pyproject.toml:
  • Test discovery patterns for test_*.py and *_test.py files
  • Coverage reporting in HTML, XML, and terminal formats
  • Strict configuration and custom markers (unit, integration, slow)
  • Configured to cover the webapp package

Directory Structure

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

Shared Test Fixtures

The tests/conftest.py provides common fixtures:

• temp_dir - Temporary directory for file operations
• temp_file - Temporary file with test content
• mock_config - Mock configuration object
• mock_flask_app - Mock Flask app instance
• clean_environment - Environment variable cleanup
• sample_data - Sample data for testing

Updated Configuration

• Enhanced .gitignore with Python, testing, and development-related entries
• Coverage configuration to exclude test files and virtual environments
• Proper TOML formatting with escaped regex patterns

Running Tests

Install Dependencies

poetry install

Run All Tests

poetry run pytest

Run Tests Without Coverage

poetry run pytest --no-cov

Run Specific Test Categories

poetry run pytest -m unit      # Unit tests only
poetry run pytest -m integration  # Integration tests only
poetry run pytest -m slow      # Slow tests only

Generate Coverage Reports

Coverage reports are automatically generated:

• HTML Report: htmlcov/index.html
• XML Report: coverage.xml
• Terminal: Shows missing lines

Validation

The setup includes validation tests (test_setup_validation.py) that verify:

• ✅ Python version compatibility (3.8+)
• ✅ Project structure integrity
• ✅ Testing directory structure
• ✅ Shared fixtures functionality
• ✅ Pytest markers configuration

All validation tests pass successfully, confirming the infrastructure is ready for use.

Notes

• The original requirements.txt is preserved for compatibility
• Poetry lock file is included in version control for reproducible builds
• Coverage threshold is set to 80% but can be adjusted in pyproject.toml
• The infrastructure is ready for immediate use - developers can start writing tests for the webapp components

Next Steps

Developers can now:

1. Write unit tests for webapp/cards.py and webapp/routes.py
2. Create integration tests for Flask routes and templates
3. Add more specific fixtures as needed
4. Utilize the existing shared fixtures for common test scenarios