@Override
    public Map<String, List<TopicPartition>> assign(Map<String, Integer> partitionsPerTopic,
                                                    Map<String, Subscription> subscriptions) {
        Map<String, List<TopicPartition>> assignment = new HashMap<>();
        List<MemberInfo> memberInfoList = new ArrayList<>();
        for (Map.Entry<String, Subscription> memberSubscription : subscriptions.entrySet()) {
            assignment.put(memberSubscription.getKey(), new ArrayList<>());
            memberInfoList.add(new MemberInfo(memberSubscription.getKey(),
                                              memberSubscription.getValue().groupInstanceId()));
        }

        CircularIterator<MemberInfo> assigner = new CircularIterator<>(Utils.sorted(memberInfoList));

        for (TopicPartition partition : allPartitionsSorted(partitionsPerTopic, subscriptions)) {
            final String topic = partition.topic();
            while (!subscriptions.get(assigner.peek().memberId).topics().contains(topic))
                assigner.next();
            assignment.get(assigner.next().memberId).add(partition);
        }
        return assignment;
    }
@Test
    public void testOneConsumerNoTopic() {
        Map<String, Integer> partitionsPerTopic = new HashMap<>();

        Map<String, List<TopicPartition>> assignment = assignor.assign(partitionsPerTopic,
                Collections.singletonMap(consumerId, new Subscription(Collections.emptyList())));
        assertEquals(Collections.singleton(consumerId), assignment.keySet());
        assertTrue(assignment.get(consumerId).isEmpty());
    }