@Test
  public void testOneRegionTable() throws IOException {
    TableName tn = TableName.valueOf(this.name.getMethodName());
    TEST_UTIL.createTable(tn, HConstants.CATALOG_FAMILY);
    List<RegionInfo> ris = MetaTableAccessor.getTableRegions(TEST_UTIL.getConnection(), tn);
    MasterServices services = TEST_UTIL.getHBaseCluster().getMaster();
    services.getCatalogJanitor().scan();
    deleteRegion(services, ris.get(0));
    services.getCatalogJanitor().scan();
    CatalogJanitorReport report = services.getCatalogJanitor().getLastReport();
    ris = MetaTableAccessor.getTableRegions(TEST_UTIL.getConnection(), tn);
    assertTrue(ris.isEmpty());
    MetaFixer fixer = new MetaFixer(services);
    fixer.fixHoles(report);
    report = services.getCatalogJanitor().getLastReport();
    assertTrue(report.isEmpty());
    ris = MetaTableAccessor.getTableRegions(TEST_UTIL.getConnection(), tn);
    assertEquals(0, ris.size());
  }
Just make sure running fixMeta does right thing for the case of a single-region Table where the
region gets dropped. There is nothing much we can do. We can't restore what we don't know about
(at least from a read of hbase:meta).
hbase-server/src/test/java/org/apache/hadoop/hbase/master/janitor/TestMetaFixer.java