public virtual void TestAllReplicasOnSameRack()
        {
            Configuration conf = new HdfsConfiguration();

            conf.Unset(DFSConfigKeys.NetTopologyScriptFileNameKey);
            fsn = Org.Mockito.Mockito.Mock <FSNamesystem>();
            Org.Mockito.Mockito.DoReturn(true).When(fsn).HasWriteLock();
            Org.Mockito.Mockito.DoReturn(true).When(fsn).HasReadLock();
            bm = new BlockManager(fsn, conf);
            // Add nodes on two racks
            AddNodes(nodes);
            // Added a new block in blocksMap and all the replicas are on the same rack
            BlockInfoContiguous blockInfo = AddBlockOnNodes(1, rackA);

            // Since the network toppolgy is multi-rack, the blockHasEnoughRacks
            // should return false.
            NUnit.Framework.Assert.IsFalse("Replicas for block is not stored on enough racks"
                                           , bm.BlockHasEnoughRacks(blockInfo));
        }