A simple pytest plugin that provides some helpful fixtures for testing Tornado
 (version 5.0 or newer) apps and easy handling of plain (undecoratored) native
 coroutine tests (Python 3.5+).
 .
 Why another Tornado pytest plugin when the excellent pytest-tornado already
 exists? The main reason is that I didn't want to have to decorate every test
 coroutine with @pytest.mark.gen_test. This plugin doesn't have anything like
 gen_test. Defining a test with async def and a name that begins with test_ is
 all that is required.