Test scripts are named test_xxx.py and use the unittest module. A base class and helper functions can be found in helper.py.

Install:

pip install pytest pytest-cov

To run an individual test:

pytest Tests/test_image.py

Or:

pytest -k test_image.py

Run all the tests from the root of the Pillow source distribution:

pytest

Or with coverage:

pytest --cov PIL --cov-report term
coverage html
open htmlcov/index.html