map.put(s1, regions);
regions.add(RegionReplicaUtil.getRegionInfoForReplica(regions.get(0), 1));
// until the step above s1 holds two replicas of a region
regions = randomRegions(1);
map.put(s2, regions);
assertTrue(loadBalancer.needsBalance(new Cluster(master, map, null, null, null, null, null)));
// check for the case where there are two hosts on the same rack and there are two racks
// and both the replicas are on the same rack
map.clear();
regions = randomRegions(1);
List<HRegionInfo> regionsOnS2 = new ArrayList<HRegionInfo>(1);
regionsOnS2.add(RegionReplicaUtil.getRegionInfoForReplica(regions.get(0), 1));
map.put(s1, regions);
map.put(s2, regionsOnS2);
// add another server so that the cluster has some host on another rack
map.put(ServerName.valueOf("host2", 1000, 11111), randomRegions(1));
assertTrue(loadBalancer.needsBalance(new Cluster(master, map, null, null, null, null,
new ForTestRackManagerOne())));
}