@Before
  public void setUp() throws Exception {
    TEST_UTIL.getConfiguration().set(WALFactory.WAL_PROVIDER, walProvider);
    TEST_UTIL.startMiniCluster(2);

    cluster = TEST_UTIL.getHBaseCluster();
    dfsCluster = TEST_UTIL.getDFSCluster();
    admin = TEST_UTIL.getAdmin();
    conf = TEST_UTIL.getConfiguration();
    fs = TEST_UTIL.getDFSCluster().getFileSystem();

    // disable region rebalancing (interferes with log watching)
    cluster.getMaster().balanceSwitch(false);
    CommonFSUtils.setRootDir(conf, HBASEDIR);
    CommonFSUtils.setWALRootDir(conf, HBASELOGDIR);
  }
Tests for conditions that should trigger RegionServer aborts when rolling the current WAL fails.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestLogRollAbort.java