@After
  public void tearDown() throws IOException {
    // Region may have been closed, but it is still no harm if we close it again here using HTU.
    HBaseTestingUtil.closeRegionAndWAL(region);
    EnvironmentEdgeManagerTestHelper.reset();
    LOG.info("Cleaning test directory: " + TEST_UTIL.getDataTestDir());
    TEST_UTIL.cleanupTestDir();
  }
Basic stand-alone testing of HRegion. No clusters! A lot of the meta information for an HRegion
now lives inside other HRegions or in the HBaseMaster, so only basic testing is possible.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegion.java