/** * Check that the NameNode is not attempting to cache anything. */ private void checkPendingCachedEmpty(MiniDFSCluster cluster) throws Exception { cluster.getNamesystem().readLock(); try { final DatanodeManager datanodeManager = cluster.getNamesystem().getBlockManager().getDatanodeManager(); for (DataNode dn : cluster.getDataNodes()) { DatanodeDescriptor descriptor = datanodeManager.getDatanode(dn.getDatanodeId()); Assert.assertTrue("Pending cached list of " + descriptor + " is not empty, " + Arrays.toString(descriptor.getPendingCached().toArray()), descriptor.getPendingCached().isEmpty()); } } finally { cluster.getNamesystem().readUnlock(); } }