anchor.diff:              fun(Key, DBAcc) ->
                   ?TEST_DB:delete(DBAcc, Key)
               end, DB1, ToDelete),
  -    ExpData = lists:foldl(
  -            fun(Key, AccIn) ->
  -                lists:keydelete(Key, 1, AccIn)
  -            end, ScrubedData, ToDelete),
  -    check_db(DB2, ExpData, "check_db_put1"),
  +    ExpData = lists:filter(
  +                fun(El) ->
  +                        not lists:any(fun(Key) ->
  +                                          element(1, El) ?EQ Key
  +                                  end, ToDelete)
  +                end, ScrubedData),
  +    check_db(DB2, ExpData, "check_db_delete"),
       ?TEST_DB:close(DB2),
       true.
   
  
positive.code: %% @author Jan Fajerski <fajerski@zib.de>
  %% @doc    Unit tests for db backends that fullfill src/backend_beh.erl.
  %%         just define ?TEST_DB and include this file.
  %% @end
  %% @version $Id$
  
  -include("scalaris.hrl").
  -include("unittest.hrl").
  
  tests_avail() ->
      [tester_put,
  
negative.code:                          write_scrubed_to_db(?TEST_DB:new(randoms:getRandomString()),
                                               Data),
      {ExpInInterval, _NotIn} = lists:partition(
                                  fun(E) ->
                                          is_in(Interval, element(1, E))
                                  end,
                                  ScrubedData),
      ExpInIntervalCounted = lists:sublist(lists:reverse(lists:keysort(1, ExpInInterval)), MaxNum),
      AllFold = ?TEST_DB:foldr(DB1, fun(E, AccIn) -> [E | AccIn] end, []),
      IntervalFold = ?TEST_DB:foldr(DB1,
                                   fun(E, AccIn) -> [E | AccIn] end,
  