### Question:
ClusterService { public Collection<Cluster> listClusters() { return clusters.values(); } @Inject  ClusterService(StormEngine stormEngine, StreamflowConfig streamflowConfig); Collection<Cluster> listClusters(); Cluster addCluster(Cluster cluster); Cluster getCluster(String clusterId); void deleteCluster(String clusterId); void updateCluster(String clusterId, Cluster cluster); ClusterSummary getClusterSummary(String clusterId);  }### Answer:
@Test public void listClusters() { Collection<Cluster> clusters = clusterService.listClusters(); assertEquals("Default config should produce two clusters", 2, clusters.size()); }