feat: Add comprehensive Python testing infrastructure

[llbbl]

Add Python Testing Infrastructure

Summary

This PR adds a complete testing infrastructure to the Python project, providing developers with a ready-to-use testing environment for writing and running tests.

Changes Made

Package Management

• Added Poetry configuration (pyproject.toml) with existing dependencies migrated from requirements.txt
• Dependencies: streamlit, openai as production dependencies
• Testing dependencies: pytest, pytest-cov, pytest-mock in test group

Testing Configuration

• Comprehensive pytest configuration with test discovery patterns, coverage settings (30% threshold), and custom markers (unit, integration, slow)
• Coverage reporting configured for HTML, XML, and terminal output formats
• Strict pytest options enabled for better test reliability

Directory Structure

• Organized test structure:
  • tests/ - Main test directory with __init__.py
  • tests/unit/ - Unit tests directory
  • tests/integration/ - Integration tests directory
  • tests/conftest.py - Shared fixtures and configuration

Testing Utilities

• Comprehensive fixtures including:
  • temp_dir - Temporary directory for tests
  • mock_openai_api - Mock OpenAI API responses
  • mock_streamlit - Mock Streamlit components
  • mock_env_vars - Mock environment variables
  • sample_email_data - Test data fixtures
• Validation tests to ensure the infrastructure works correctly

Development Setup

• Updated .gitignore with testing-related entries, build artifacts, and Claude settings
• Poetry lock file properly configured (not ignored in git)
• Coverage configuration targeting the main streamlit_app.py file

Running Tests

Install Dependencies

poetry install

Run All Tests

poetry run pytest

Run Tests with Verbose Output

poetry run pytest -v

Run Tests by Marker

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 Report

poetry run pytest --cov-report=html
# View report: open htmlcov/index.html

Testing Infrastructure Features

• ✅ Poetry package management with proper dependency isolation
• ✅ Pytest framework with comprehensive configuration
• ✅ Coverage reporting with HTML/XML/terminal outputs
• ✅ Custom test markers for test categorization
• ✅ Shared fixtures for common testing scenarios
• ✅ Mock utilities for external dependencies (OpenAI, Streamlit)
• ✅ Organized directory structure for scalable test organization
• ✅ Validation tests to verify infrastructure functionality

Notes

• Coverage threshold: Set to 30% for initial setup (can be increased as tests are added)
• Test discovery: Configured to find test_*.py and *_test.py files
• Dependencies: All testing dependencies are isolated in the test group
• Poetry scripts: Use poetry run pytest directly for running tests

The testing infrastructure is now ready for developers to start writing unit and integration tests immediately.

🤖 Generated with Claude Code