@Test
  public void testReversedScanAtRegionBoundary() throws Exception {
    testReversedScan(333, true, 222, true, -1);
    testReversedScan(444, true, 333, false, -1);
    testReversedScan(555, false, 444, true, -1);
    testReversedScan(666, false, 555, false, -1);
  }
Used by implementation classes to assert the correctness of spans having errors.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/AbstractTestAsyncTableScan.java