private void moveBuckets() throws InterruptedException {
    // Move some data, to force a rebalance
    Region<Object, Object> base = getCache().getRegion(BASE);
    Set<DistributedMember> allMembersForKey =
        PartitionRegionHelper.getAllMembersForKey(base, 0);

    Iterator<DistributedMember> memberIterator = allMembersForKey.iterator();
    DistributedMember member1 = memberIterator.next();
    DistributedMember member2 = memberIterator.next();

    RebalanceResults results = PartitionRegionHelper.moveData(base, member1, member2, 100);
    assertThat(results.getTotalBucketTransfersCompleted()).isGreaterThan(1);
  }
This is a regression test for GEODE-6767 that we can still rebalance after altering certain
partitioned region attributes.

Altering the region attributes changes metadata in the __PR region. If that metadata is
corrupted, rebalance may end up reducing redundancy due to the fact that
isColocationComplete=false
in the metadata.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/partitioned/PartitionedRegionAttributesMutatorDUnitTest.java