feat: Set up complete testing infrastructure with Poetry

[llbbl]

Set up Complete Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the StreamDiffusion NDI project, migrating from a basic requirements.txt setup to a professional Poetry-managed development environment with full testing capabilities.

Key Changes Made

• 📦 Package Management: Migrated from requirements.txt to Poetry with proper dependency management
• 🧪 Testing Framework: Set up pytest with comprehensive configuration including coverage reporting
• 📁 Directory Structure: Created organized test directories (tests/unit/, tests/integration/)
• 🔧 Configuration: Added complete testing configuration in pyproject.toml
• 📋 Fixtures: Created comprehensive shared fixtures in conftest.py for common testing patterns
• 📊 Coverage: Configured coverage reporting with 80% threshold, HTML and XML output formats
• 🏷️ Markers: Set up custom test markers (unit, integration, slow) for test categorization
• ⚙️ Scripts: Added Poetry scripts for easy test execution (poetry run test, poetry run tests)
• 🙈 Gitignore: Created comprehensive .gitignore with testing and development entries

Testing Infrastructure Components

Package Management

• Poetry: Modern dependency management with proper virtual environment handling
• Dependencies: All original dependencies preserved (opencv-python, python-osc)
• Optional Dependencies: ndi-python made optional due to platform compatibility

Testing Dependencies

• pytest: Main testing framework with comprehensive configuration
• pytest-cov: Coverage reporting with multiple output formats
• pytest-mock: Advanced mocking utilities for test isolation

Test Configuration Features

• Test Discovery: Automatic discovery of test files and functions
• Coverage: 80% coverage threshold with HTML, XML, and terminal reporting
• Markers: Custom markers for test categorization and selective running
• Strict Mode: Strict configuration and marker validation for reliability

Shared Fixtures Available

• temp_dir, temp_file: Temporary file system utilities
• sample_config, mock_config_file: Configuration management fixtures
• mock_opencv, mock_ndi, mock_osc_client: Mock external dependencies
• sample_image_array: Mock image data for computer vision testing
• mock_environment_vars: Environment isolation for testing
• capture_logs: Log capture and assertion utilities

Instructions for Running Tests

Basic Test Commands

# Install dependencies
poetry install

# Run all tests
poetry run test
# or
poetry run tests

# Run with verbose output
poetry run pytest -v

# Run specific test categories
poetry run pytest -m unit          # Unit tests only
poetry run pytest -m integration   # Integration tests only
poetry run pytest -m "not slow"    # Skip slow tests

Coverage Reports

# Generate HTML coverage report (opens in htmlcov/index.html)
poetry run pytest --cov-report=html

# View coverage in terminal
poetry run pytest --cov-report=term-missing

# Generate XML coverage for CI/CD
poetry run pytest --cov-report=xml

Development Workflow

# Run tests in watch mode during development
poetry run pytest --maxfail=1 -x

# Run only failed tests from last run
poetry run pytest --lf

# Show available fixtures
poetry run pytest --fixtures

Notes and Considerations

• NDI Compatibility: The ndi-python dependency was made optional due to platform-specific wheel availability issues. This ensures the testing infrastructure works across different environments.
• Coverage Threshold: Set to 80% but can be adjusted in pyproject.toml based on project requirements.
• Test Isolation: Each test runs in isolation with automatic cleanup of temporary resources.
• Future-Ready: The infrastructure supports both unit and integration testing patterns, ready for immediate use.

Validation

• ✅ All dependencies install successfully
• ✅ Test discovery finds test files correctly
• ✅ Custom markers work as expected
• ✅ Shared fixtures are properly available across tests
• ✅ Coverage reporting generates HTML, XML, and terminal output
• ✅ Poetry scripts execute tests correctly
• ✅ Test isolation prevents cross-test interference

The testing infrastructure is now ready for developers to begin writing comprehensive tests for the StreamDiffusion NDI codebase.