anchor.diff:      % skip
       dby_read(dby_db(example2())),
       ?assertEqual([<<"A">>,<<"B">>,<<"C">>,<<"E">>],
  -            lists:sort(dby:search(search_fn_skip_on(<<"B">>), <<"A">>, [],
  +            lists:sort(dby:search(search_fn_skip_on(<<"B">>), [], <<"A">>,
                                                   [breadth, {max_depth, 2}]))).
   
   % ------------------------------------------------------------------------------
  
positive.code: search9() ->
      % stop
      dby_read(dby_db(example1())),
      Order = dby:search(search_fn_stop_on(<<"C">>), <<"A">>, [],
                                                      [breadth, {max_depth, 2}]),
      % C is last identifier
      ?assertEqual(<<"C">>, lists:last(Order)).
  
negative.code:     % skip
      dby_read(dby_db(example2())),
      ?assertEqual([<<"A">>,<<"B">>,<<"C">>,<<"E">>],
              lists:sort(dby:search(search_fn_skip_on(<<"B">>), [], <<"A">>,
                                                      [depth, {max_depth, 2}]))).
  
  search6() ->
  