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 VISTA project, migrating from traditional pip/requirements.txt to Poetry for modern dependency management and setting up pytest with coverage reporting.

Changes Made

Package Management

• Migrated to Poetry: Created pyproject.toml with all dependencies from requirements.txt
• Preserved all dependencies: Maintained exact dependency specifications including version constraints
• Added development dependencies: pytest, pytest-cov, and pytest-mock

Testing Configuration

• pytest configuration in pyproject.toml:

  • Test discovery patterns for test_*.py and *_test.py files
  • Coverage reporting with 80% threshold requirement
  • Multiple output formats: terminal, HTML, and XML reports
  • Custom markers: unit, integration, and slow
  • Strict mode enabled with verbose output

• Coverage configuration:

  • Source set to vwm package
  • Branch coverage enabled
  • Exclusions for test files, __init__.py, and common patterns
  • HTML reports in htmlcov/ directory
  • XML reports for CI integration

Directory Structure

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

Test Fixtures (conftest.py)

• temp_dir: Temporary directory for test files
• mock_config: OmegaConf configuration for testing
• sample_tensor: Sample PyTorch tensors
• sample_video_tensor: Video tensors for temporal models
• mock_dataset_item: Mock dataset items
• mock_model_state: Model state dictionaries
• device: CPU/GPU device selection
• mock_checkpoint_path: Checkpoint paths
• reset_random_seeds: Reproducible tests
• mock_wandb: Mocked Weights & Biases
• mock_env_vars: Test environment variables
• capture_stdout: Output capture utility

Additional Setup

• Updated .gitignore with:
  • Testing artifacts (.pytest_cache/, .coverage, htmlcov/, coverage.xml)
  • Claude settings (.claude/*)
  • IDE files (VSCode workspace files)
• Created validation tests to verify the infrastructure

How to Use

Install Dependencies

poetry install --with dev

Run Tests

Both commands work identically:

poetry run test
# or
poetry run tests

Run with Options

# Run specific tests
poetry run test tests/unit/

# Run with markers
poetry run test -m unit
poetry run test -m "not slow"

# Run without coverage
poetry run test --no-cov

# Run specific test file
poetry run test tests/test_setup_validation.py

Coverage Reports

• Terminal: Shown by default after test run
• HTML: Open htmlcov/index.html in browser
• XML: Available at coverage.xml for CI tools

Notes

• The infrastructure is ready for developers to start writing tests
• No actual unit tests for the codebase were created - only infrastructure setup
• Poetry lock file should be committed to ensure reproducible builds
• Coverage threshold is set to 80% but can be adjusted in pyproject.toml
• The validation test that imports the main package may fail due to missing optional dependencies (like open_clip), but this doesn't affect the testing infrastructure itself

Next Steps

1. Developers can now create unit tests in tests/unit/
2. Integration tests go in tests/integration/
3. Use the provided fixtures in conftest.py for common test needs
4. Mark slow tests with @pytest.mark.slow to exclude them during rapid development