Notes on how to develop guizero (on Windows).


Upgrade pip:

python.exe -m pip install pip --upgrade

Install / upgrade pre-requisites:

pip install mkdocs wheel twine virtualenv pytest pillow --upgrade

Python library

Create a virtual environment (not essential, but a good idea!):

virtualenv guizero-[versionno]
cd guizero-[versionno]

Activate your virtual environment:


Checkout and install guizero for development:

git clone
cd guizero
git checkout dev
python develop

When you have finished your development, deactivate your virtual environment:



To run the automated tests:

cd guizero\test
pytest -v

If running the tests inside a virtual environment you will need to install pytest in that virtual environment.

pip install pytest

Note - tkinter can error when running the tests usually when the interpreter doesn't start properly, it doesn't seem to like being initialised and destroyed hundreds of times, I suspect a file locking issue as you don't see the problem on Linux. So sometimes you might get a test fail with an error like This probably means that tk wasn't installed properly.. Just re-run the last failed errors! pytest --lf -v


Test documents by serving up MkDocs:

cd guizero\docs-src
mkdocs serve