Pytest pre-commit hook

.pre-commit-config.yaml

# https://github.com/pre-commit/pre-commit/issues/761#issuecomment-394167542
-   repo: local
    hooks:
    -   id: pytest
        name: pytest
        entry: venv/bin/pytest
        language: script
        pass_filenames: false
        # alternatively you could `types: [python]` so it only runs when python files change
        # though tests might be invalidated if you were to say change a data file
        always_run: true