private static List<ClusterState> statesInBundle(ClusterStateBundle bundle) {
            List<ClusterState> states = new ArrayList<>(3);
            states.add(bundle.getBaselineClusterState());
            bundle.getDerivedBucketSpaceStates().forEach((space, state) -> states.add(state.getClusterState()));
            return states;
        }
Return null if met, why not if it is not met.
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/testutils/WaitCondition.java