def METHOD_NAME(self):
    # ensure we are not using an already existing global font manager or
    # font cache and that we have no system fonts available
    with patch_global_font_manager(None):
        with self.assertWarns(UserWarning):
            # patch_font_cache context manager triggers a FontManager
            # instantiation.  Sould not fail, but should raise warning
            with patch_font_cache(self.temp_dir, []):
                pass