MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
try {
cluster.waitActive();
FileSystem fs = cluster.getFileSystem();
NamenodeProtocols preSpyNN = cluster.getNameNodeRpc();
NamenodeProtocols spyNN = spy(preSpyNN);
DFSClient client = new DFSClient(null, spyNN, conf, null);
int maxBlockAcquires = client.getMaxBlockAcquireFailures();
assertTrue(maxBlockAcquires > 0);