@BeforeClass
  public static void setUpBeforeClass() throws Exception {
    TEST_UTIL = new HBaseTestingUtil();
    TEST_UTIL.startMiniDFSCluster(1);
  }
Tests of HRegion methods for replaying flush, compaction, region open, etc events for secondary
region replicas
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegionReplayEvents.java