clirunner VS pytypest

I love Click for building Python command line interfaces (CLI). One useful feature Click provides is a CliRunner() helper class for testing. CliRunner invokes the script in an isolated environment allowing you to pass arguments, etc. Occasionally I work on projects that don't use Click. For example, if I want to provide a python3 -m packagename script that is ancillary to the primary use case and don't want to include Click as a dependency or want something that can be distributes as a stand-alone script without dependencies. In this case I'd usually use argparse. However, CLIs built with argparse (or old-fashioned manual sys.argv parsing) aren't nearly as easy to test. Thus I created clirunner which is a port of Click's test helper to work with non-Click apps. The API is compatible with Click's CliRunner so if you ever move a project to use Click, the tests should need little to no modification.