calc-js is a simple demonstration calculator originally written for a university course on software testing. A live but not necessarily up to date version lives at https://calc-js.kaijanaho.fi/index.html The software lives completely on the browser, with no back end needed. However, it probably will not work from local file URLs, so you will need a local web server for development. The Python script server.py solves that issue (it will not be needed for a production deployment). Start development in Ubuntu or other Linux: python3 -m venv venv Each time in a new shell: . venv/bin/activate You can run the development localhost server with python3 server.py To work with the Selenium tests pip install selenium (Also make sure you have chromedriver installed.) You can then run the tests with python3 tests/selenium_tests.py PATH-TO-CHROMEDRIVER