A simple, correct PEP517 package builder—in other words a replacement for disttools/setuputils/whatever.
PEP 517: A build-system-independent format for source trees. This is an attempt to do for Python packaging what WSGI did for web frameworks: create a framework in to which appropriately simple or complex guild systems can be plugged.
HTTPretty is a Python package for writing tests for code that interacts with remote web services. You write expectations for requests the test code should make and the responses, and the tests run without accessing real networks at all. Works particularly nicely with JSON-based protocols.
pipx is a tool to help you install and run end-user applications written in Python. Each app is installed in its own virtualenv and the commands added to a directory you put on your path.