Map<Uuid, String> topicNames() {
        return topicNames;
    }
@Test
    public void testEmptyTopicNamesCacheBuiltFromTopicIds() {
        Map<String, Uuid> topicIds = new HashMap<>();

        MetadataSnapshot cache = new MetadataSnapshot("clusterId",
                Collections.singletonMap(6, new Node(6, "localhost", 2077)),
                Collections.emptyList(),
                Collections.emptySet(),
                Collections.emptySet(),
                Collections.emptySet(),
                null,
                topicIds);
        assertEquals(Collections.emptyMap(), cache.topicNames());
    }