private int getBucketCount(int server) {
    return clusterStartupRule.getVM(server).invoke(() -> {
      PartitionedRegion region =
          (PartitionedRegion) ClusterStartupRule.getCache().getRegion(REGION_NAME);
      return region.getLocalBucketsListTestOnly().size();
    });
  }
This test tests the case that we don't accidentally leave extra copies in a
redundancy zone after a server recovers.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/control/RebalanceOperationComplexDistributedTest.java