@Override
      public String explainFailure() {
        for (String label : labels) {
          if (labelsCache.getLabelOrdinal(label) == 0) {
            return label + " is not available yet";
          }
        }
        return "";
      }
Wait until labels is ready in VisibilityLabelsCache.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/HBaseTestingUtility.java