Beefore

Performs pre-merge checks (such as code style) on a pull request.

Duvet

Coverage visualization tool

Briefcase

Tools to support converting a Python project into a standalone native application.

Cricket

Test runner GUI that finds failures fast

Bugjar

A interactive graphical debugger for Python code.

Galley

A GUI tool for reviewing RST/Sphinx documentation

A tool is a special class of application that is installed into a Python virtual environment. Tools are used to assist when developing standalone applications, in roles from debugging and testing to packaging.