@Test
  public void testHoles() throws IOException, InterruptedException {
    CatalogJanitor janitor = TEST_UTIL.getHBaseCluster().getMaster().getCatalogJanitor();

    CatalogJanitorReport report = janitor.getLastReport();
    // Assert no problems.
    assertTrue(report.isEmpty());
    // Verify start and end region holes
    verifyCornerHoles(janitor, T1);
    // Verify start and end region holes
    verifyCornerHoles(janitor, T2);
    // Verify start and end region holes when next table is disable see: HBASE-27560
    disableTable(T7);
    verifyCornerHoles(janitor, T6);
    verifyMiddleHole(janitor);
    // Verify that MetaFixer is able to fix these holes
    fixHoles(janitor);
  }
Take last byte and add one to it.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/janitor/TestCatalogJanitorCluster.java