anchor.diff:           %% 2nd truncate
            LogId2 = InitLogId + 9,
            {SegId2, _} = locate("./", Idx13, LogId2),
  -         {Idx14, Truncated2} = truncate("./", Idx13, SegId2, LogId2, undefined),
  +         {Idx14, Truncated2} = truncate("./", Idx13, SegId2, LogId2, "./backup/"),
            ?assertEqual([gululog_name:mk_idx_name("./", 7)], Truncated2),
  +         ?assertEqual([gululog_name:mk_idx_name("./backup/", 7)],
  +                       gululog_name:wildcard_idx_name_reversed("./backup")),
            %% 3rd truncate
            LogId3 = InitLogId + 3,
            {Segid3, _} = locate("./", Idx14, LogId3),
  
positive.code:          [file:delete(X) || X <- gululog_name:wildcard_idx_name_reversed("./")
                                ++ gululog_name:wildcard_seg_name_reversed("./")],
           Idx1 = init("./"),
           InitLogId = get_next_logid(Idx1),
           Idx2 = append(Idx1, InitLogId + 0, 10),
           Idx3 = append(Idx2, InitLogId + 1, 20),
           Idx4 = append(Idx3, InitLogId + 2, 30),
  
negative.code:          ?assertEqual(Expect2, ets:tab2list(NewEtsTable)),
           flush_close(NewIdx),
           [file:delete(X) || X <- gululog_name:wildcard_idx_name_reversed("./")
                                ++ gululog_name:wildcard_seg_name_reversed("./")],
           [file:delete(X) || X <- gululog_name:wildcard_idx_name_reversed("./backup")],
           ok
         end}
    ].
  
  -endif.
  
  