AttributeError in postorius/views/list.py

Commit c046f2ed added the following to postorius/views/list.py

        if getattr(settings, 'TESTING') and \
                'hyperkitty' not in settings.INSTALLED_APPS:
            # avoid systematic test failure when HyperKitty is installed
            # (missing VCR request, see below).
            list(self.mailing_list.archivers)

The problem is most existing configurations don't define TESTING so getattr(settings, 'TESTING') throws AttributeError. There should be a default provided to avoid this. E.g., getattr(settings, 'TESTING', False).