[Checkins] [zopefoundation/zope.interface] d49f8e: Add test case for #6.

[Jason Madden]

  Branch: refs/heads/issue6
  Home:   https://github.com/zopefoundation/zope.interface
  Commit: d49f8e205d36f1a3dceca228b3bc19d9cca57624
      https://github.com/zopefoundation/zope.interface/commit/d49f8e205d36f1a3dceca228b3bc19d9cca57624
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2020-02-14 (Fri, 14 Feb 2020)

  Changed paths:
    M src/zope/interface/tests/test_interface.py

  Log Message:
  -----------
  Add test case for #6.

It seems to be working now, so this fixes #6