### Question:
StreamPartitionAssignor implements PartitionAssignor, Configurable { Cluster clusterMetadata() { if (metadataWithInternalTopics == null) { return Cluster.empty(); } return metadataWithInternalTopics; }  @Override void configure(Map<String, ?> configs); @Override String name(); @Override Subscription subscription(Set<String> topics); @Override Map<String, Assignment> assign(Cluster metadata, Map<String, Subscription> subscriptions); @Override void onAssignment(Assignment assignment); void close(); final static int NOT_AVAILABLE; }### Answer:
@Test public void shouldReturnEmptyClusterMetadataIfItHasntBeenBuilt() throws Exception { final Cluster cluster = partitionAssignor.clusterMetadata(); assertNotNull(cluster); }