feat: Set up comprehensive Python testing infrastructure with Poetry

[llbbl]

Set up Python Testing Infrastructure

Summary

This PR establishes a comprehensive testing infrastructure for the GNN Explainer Python project using Poetry as the package manager and pytest as the testing framework.

Changes Made

Package Management

• Poetry Configuration: Created pyproject.toml with Poetry setup as the primary package manager
• Dependency Migration: Migrated existing dependencies from requirements.txt to Poetry format
• Development Dependencies: Added pytest, pytest-cov, and pytest-mock as dev dependencies

Testing Framework Setup

• pytest Configuration:

  • Configured test discovery patterns
  • Added custom markers (unit, integration, slow)
  • Set up coverage reporting with multiple output formats
  • Configured strict mode for markers and configuration

• Coverage Configuration:

  • Set 80% coverage threshold
  • Configured HTML and XML report generation
  • Added exclusion patterns for test files and boilerplate code

Directory Structure

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

Testing Fixtures (conftest.py)

• temp_dir: Temporary directory management
• mock_config: Mock configuration object
• sample_graph: NetworkX graph for testing
• sample_tensor_data: PyTorch tensor data samples
• mock_model: Simple neural network model
• capture_stdout: Stdout capture utility
• reset_random_seeds: Reproducibility fixture
• mock_data_loader: PyTorch DataLoader mock
• cleanup_files: File cleanup helper
• mock_logger: Logger mocking

Additional Setup

• Updated .gitignore with testing artifacts and Poetry files
• Created validation tests to verify the infrastructure works correctly
• Configured Poetry scripts for running tests

How to Use

Install Dependencies

poetry install

Run Tests

Both commands work:

poetry run test
poetry run tests

Run Tests with Coverage

poetry run pytest --cov=explainer --cov=utils --cov-report=html

Run Specific Test Categories

poetry run pytest -m unit        # Run only unit tests
poetry run pytest -m integration # Run only integration tests
poetry run pytest -m "not slow"  # Skip slow tests

Notes

• The testing infrastructure is designed to work even when main project dependencies aren't fully installed
• Fixtures gracefully handle missing dependencies (e.g., torch, networkx)
• Coverage reporting is configured but can be customized per project needs
• The validation test suite ensures all components work correctly

Next Steps

Developers can now immediately start writing tests by:

1. Creating test files in tests/unit/ or tests/integration/
2. Using the provided fixtures from conftest.py
3. Running tests with the configured commands

The infrastructure is ready for Test-Driven Development (TDD) practices.