feat: Set up comprehensive Python testing infrastructure

[llbbl]

Python Testing Infrastructure Setup

Summary

This PR establishes a complete testing infrastructure for the Python project, providing all the necessary tools and configurations for developers to immediately start writing tests.

Changes Made

Package Management

• Detected existing UV configuration in pyproject.toml
• Added testing dependencies as optional dependencies:
  • pytest>=7.2 - Main testing framework
  • pytest-cov>=4.1.0 - Coverage reporting
  • pytest-mock>=3.12.0 - Mocking utilities

Testing Configuration

Added comprehensive testing configuration in pyproject.toml:

• pytest settings:

  • Test discovery patterns for test_*.py and *_test.py files
  • Configured test paths to tests/ directory
  • Added custom markers: unit, integration, slow
  • Enabled strict marker validation
  • Set up verbose output and error reporting

• Coverage settings:

  • Source directory set to src/
  • Branch coverage enabled
  • HTML and XML report generation
  • Coverage threshold currently set to 0% (should be updated to 80% once tests are written)
  • Excluded test files and common patterns from coverage

Directory Structure

Created organized testing structure:

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

Testing Fixtures

Implemented comprehensive fixtures in conftest.py:

• temp_dir - Temporary directory management
• temp_file - Temporary file creation
• mock_config - Configuration dictionary for testing
• mock_environment - Environment variable mocking
• mock_logger - Logger mocking
• sample_data - Sample data structures
• mock_model - Model mocking with common methods
• mock_file_system - Complete file system structure mocking
• capture_stdout - Stdout capture for testing print statements
• reset_singletons - Singleton instance reset between tests

Validation Tests

Created test_setup_validation.py to verify:

• All testing dependencies are properly installed
• Custom fixtures are working correctly
• Test markers are recognized
• Python version meets requirements
• Source modules are importable

Additional Setup

• Updated .gitignore to exclude:
  • .pytest_cache/
  • .coverage
  • htmlcov/
  • coverage.xml
  • .claude/*
• Configured test commands accessible via standard pytest invocation

How to Run Tests

Install dependencies:

pip install -e ".[test]"  # or pip install -e ".[dev]"

Run all tests:

python -m pytest

Run with specific options:

# Run only unit tests
python -m pytest -m unit

# Run only integration tests  
python -m pytest -m integration

# Run without coverage
python -m pytest --no-cov

# Run specific test file
python -m pytest tests/test_setup_validation.py

# Run with maximum verbosity
python -m pytest -vv

View coverage report:

# After running tests, open HTML report
open htmlcov/index.html

Notes

• The coverage threshold is currently set to 0% to allow the infrastructure to be set up without existing tests
• Once actual tests are written, update --cov-fail-under=0 to --cov-fail-under=80 in pyproject.toml
• The project uses UV for dependency management, which is already configured
• All validation tests pass successfully, confirming the infrastructure is ready for use

Next Steps

Developers can now:

1. Write unit tests in tests/unit/
2. Write integration tests in tests/integration/
3. Use the provided fixtures for common testing scenarios
4. Run tests with coverage reporting to track progress