feat: Set up comprehensive Python testing infrastructure

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the KiteSublime project, providing developers with a ready-to-use testing environment that includes all necessary tooling and configuration.

Changes Made

Package Management & Dependencies

• Poetry Setup: Added pyproject.toml with Poetry configuration as the package manager
• Testing Dependencies: Added pytest, pytest-cov, and pytest-mock as development dependencies
• Version Management: Configured Python 3.7+ compatibility

Testing Configuration

• pytest Configuration: Comprehensive pytest setup in pyproject.toml with:
  • Test discovery patterns for various naming conventions
  • Coverage reporting with 80% threshold requirement
  • HTML and XML coverage report generation
  • Custom markers: unit, integration, slow
  • Strict configuration and verbose output

Directory Structure

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

Shared Testing Fixtures

Created comprehensive fixtures in tests/conftest.py:

• Sublime Text Mocks: mock_sublime, mock_view, mock_window, mock_settings
• File System Utilities: temp_dir, temp_file for temporary test resources
• Sample Data: sample_python_code, kite_response_mock for consistent test data
• Configuration Mocks: mock_kite_settings, mock_platform_info

Coverage Configuration

• Source Tracking: Configured to track coverage for lib/ directory
• Exclusions: Properly excludes test files, vendor code, and cache directories
• Reporting: Multiple formats (terminal, HTML, XML) for different use cases
• CI/CD Ready: XML output compatible with most CI/CD platforms

Development Workflow

• Gitignore Updates: Added comprehensive entries for Python artifacts, testing files, coverage reports, and IDE files
• Validation: Included validation tests to ensure infrastructure works correctly

Running Tests

Install Dependencies

poetry install

Run All Tests

poetry run pytest

Run with Coverage

poetry run pytest --cov=lib --cov-report=html

Run Specific Test Types

# Unit tests only
poetry run pytest -m unit

# Integration tests only  
poetry run pytest -m integration

# Exclude slow tests
poetry run pytest -m "not slow"

View Coverage Report

After running tests with coverage, open htmlcov/index.html in a browser for detailed coverage analysis.

Validation

✅ All dependencies install correctly
✅ pytest discovers and runs tests successfully
✅ Coverage reporting generates HTML and XML outputs
✅ Custom markers work as expected
✅ Shared fixtures are available across test modules
✅ Validation tests pass confirming infrastructure setup

Notes

• The 80% coverage threshold is configured but will only apply when actual tests are written for the codebase
• Poetry lock file is included and should be committed to ensure consistent dependency versions
• All testing artifacts (coverage reports, cache files) are properly gitignored
• The infrastructure is ready for immediate use - developers can start writing tests in the tests/unit/ and tests/integration/ directories

Next Steps

With this infrastructure in place, developers can:

1. Start writing unit tests for individual modules in tests/unit/
2. Create integration tests for component interactions in tests/integration/
3. Use the provided fixtures to mock Sublime Text components consistently
4. Monitor code coverage and maintain the 80% threshold as the test suite grows