feat: Add comprehensive Python testing infrastructure with Poetry

[llbbl]

Add Comprehensive Python Testing Infrastructure

Summary

This PR establishes a complete testing infrastructure for the Hadoop JMX Exporter project, providing a solid foundation for writing and running tests.

Changes Made

Package Management

• Set up Poetry as the primary package manager
• Migrated dependencies from requirements.txt to pyproject.toml
• Created poetry.lock file for reproducible dependency management

Testing Framework

• Added pytest as the main testing framework with the following plugins:
  • pytest-cov for coverage reporting
  • pytest-mock for enhanced mocking capabilities
• Configured comprehensive pytest settings in pyproject.toml:
  • Test discovery patterns for files, classes, and functions
  • Coverage reporting with 80% threshold
  • HTML and XML coverage report generation
  • Custom test markers: unit, integration, slow
  • Strict configuration for better error detection

Project Structure

• Created organized testing directory structure:

  tests/
  ├── __init__.py
  ├── conftest.py          # Shared fixtures and configuration
  ├── unit/                # Unit tests
  │   └── __init__.py
  ├── integration/         # Integration tests
  │   └── __init__.py
  └── test_infrastructure.py  # Validation tests
  

Shared Testing Utilities

• Created comprehensive fixtures in conftest.py:
  • temp_dir: Temporary directory management
  • mock_requests_response: HTTP response mocking
  • sample_jmx_response: Sample JMX data for testing
  • mock_prometheus_registry: Prometheus registry mocking
  • sample_config: Configuration data for tests
  • mock_yaml_config: YAML configuration file creation
  • reset_prometheus_registry: Auto-cleanup for Prometheus metrics

Coverage Configuration

• Configured coverage.py for comprehensive code coverage:
  • Source directory inclusion with proper exclusions
  • HTML reports in htmlcov/ directory
  • XML reports for CI/CD integration
  • Excluding common non-testable code patterns

Development Environment

• Updated .gitignore with comprehensive exclusions:
  • Python bytecode and build artifacts
  • Virtual environments and IDE files
  • Testing artifacts (.pytest_cache, coverage reports)
  • OS-specific files and Claude Code settings

How to Run Tests

Install Dependencies

poetry install

Run All Tests

poetry run pytest

Run Tests by Category

# 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"

Generate Coverage Reports

# Coverage included automatically in test runs
poetry run pytest

# View HTML coverage report
open htmlcov/index.html

Validation

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

• ✅ Python version compatibility (3.8+)
• ✅ Project structure integrity
• ✅ Dependency imports work correctly
• ✅ Custom pytest markers are functional
• ✅ Shared fixtures are available and working

Next Steps

With this testing infrastructure in place, developers can now:

1. Write unit tests for individual modules (place in tests/unit/)
2. Write integration tests for end-to-end functionality (place in tests/integration/)
3. Use the provided fixtures for consistent test setup
4. Monitor code coverage to ensure comprehensive testing
5. Run tests easily with Poetry commands

The infrastructure is designed to grow with the project while maintaining consistency and best practices.

---

🤖 Generated with Claude Code

Co-Authored-By: Claude noreply@anthropic.com