After forking the pyparsing repo, and cloning your fork locally, install the libraries needed to run tests

pip install -Ur tests/requirements.txt
pre-commit install

Run the simple unit tests to ensure your environment is setup

python tests/test_simple_unit.py

Use tox to run the full test suite on all supported Python versions

# run a specific test environment
tox -e py312

# run all test environments
tox

# run all test environments in parallel
tox -p

To run mypy standalone

tox -e mypy-check