@After
  public void tearDown() throws IOException {
    if (region != null) {
      HBaseTestingUtil.closeRegionAndWAL(region);
    }
  }
A UT to make sure that everything is fine when we fail to load bloom filter.
<p>
See HBASE-27936 for more details.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestBloomFilterFaulty.java