Allow to execute classmethods without instantiating the class if possible

I would like to run a test function with pytest without having to set up a pytest.ini, using only command line arguments. The test function is a class method with no arguments (not an instance method). It is named 'test' and defined in the 'Stack' class in the current directory's file, "stack.py". The code can be seen here.

However, calling:

  pytest stack.py::Stack::test

fails to work as shown below. Is there any way to make this work with a change in syntax or is this a bug?

========================================================================
test session starts
========================================================================
platform darwin -- Python 3.6.2, pytest-3.2.3, py-1.4.34, pluggy-0.4.0
rootdir: /Users/rsw/rsw_py_stack, inifile:
collecting 0 items                                                                                                                                                   
===================================================================
no tests ran in 0.00 seconds 
====================================================================
ERROR: not found: /Users/rsw/rsw_py_stack/stack.py::Stack::test
(no name '/Users/rsw/rsw_py_stack/stack.py::Stack::test' in any of [<Module 'stack.py'>])

Start by reproducing the command pytest stack.py::Stack::test against the linked example, then trace how pytest collects the Stack class and its classmethod. Done means the command-line target is found and the no-argument classmethod runs without requiring pytest.ini or an instance.