Shorthand command for running the unit tests defined for Config Rules
that use a Python runtime. When a Python 3.7+ Rule is created using the
create command a unit test template is created in the Rule directory.
This test boilerplate includes minimal tests, as well as a framework for
using the unittest.mock library for stubbing out Boto3 calls. This
allows more sophisticated test cases to be written for Periodic rules
that need to make API calls to gather information about the environment.