def METHOD_NAME(self, service):
    """Test retrieving backends when a config is missing."""
    service._backend_configs = {}
    instance = service._account.instance
    backends = service.backends(instance=instance)
    configs = service._backend_configs
    configs["test_backend"] = None
    backend_names = [backend.name for backend in backends]
    # check filters still work
    service.backends(instance=instance, simulator=True)
    for config in configs.values():
        backend = service._create_backend_obj(config, instance=instance)
        if backend:
            self.assertTrue(backend.name in backend_names)