@Before
  public void setUp() {
    RNG.setSeed(91238123L);
    expectedKVs.clear();
    TEST_UTIL.getConfiguration().setInt(BloomFilterUtil.PREFIX_LENGTH_KEY, 10);
  }
Disable this when this test fails hopelessly and you need to debug a simpler case.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSeekOptimizations.java