anchor.diff:      H2 = histogram_rt:add(Key1, H),
       H3 = histogram_rt:add(Key2, H2),
       %% check results
  -    case nodelist:succ_ord_id(Key1, Key2, BaseKey) of
  -        true -> SplitKey = ?RT:get_split_key(Key1, Key2, {1,2});
  -        false -> SplitKey = ?RT:get_split_key(Key2, Key1, {1,2})
  +    case Key1 =:= Key2 of
  +        true -> SplitKey = Key1;
  +        false ->
  +            case nodelist:succ_ord_id(Key1, Key2, BaseKey) of
  +                true -> SplitKey = ?RT:get_split_key(Key1, Key2, {1,2});
  +                false -> SplitKey = ?RT:get_split_key(Key2, Key1, {1,2})
  +            end
       end,
  -    ?equals(histogram_rt:get_data(H3), [{SplitKey, 2}]),
  +    %ct:pal("Key1: ~p Key2: ~p BaseKey: ~p SplitKey: ~p Result: ~p, Raw: ~p", [Key1, Key2, BaseKey, SplitKey, histogram_rt:get_data(H3), histogram:get_data(element(1, H3))]),
  +    ?compare(fun(Actual, Expected) -> check_result(Actual, Expected, BaseKey) end, histogram_rt:get_data(H3), [{SplitKey, 2}]),
       true.
   
   merge_keys(_Config) ->
       tester:test(?MODULE, prop_merge_keys, 3, 250, [{threads, 2}]).
  +
  +check_result(Actual, Expected, BaseKey) ->
  +    case ?RT of
  +        rt_chord ->
  +            ?equals(Actual, Expected);
  +        _ ->
  +            check_elements(Actual, Expected, BaseKey)
  +    end.
  +
  +check_elements([], [], _BaseKey) ->
  +    true;
  +check_elements([{El1, Count1} | Rest], [{El2, Count2} | Rest2], BaseKey) ->
  +    %ct:pal("El: ~p, El2:~p", [El1, El2]),
  +    case nodelist:succ_ord_id(El1, El2, BaseKey) of
  +        true -> Range = ?RT:get_range(El1, El2);
  +        false -> Range = ?RT:get_range(El2, El1)
  +    end,
  +    %ct:pal("Range: ~p", [Range]),
  +    %ct:pal("Check: ~p", [Range < Epsilon orelse Range == ?RT:n()]),
  +    ?assert(Range < ?EPSILON orelse El1 =:= El2),
  +    ?equals(Count1, Count2),
  +    check_elements(Rest, Rest2, BaseKey).
  
positive.code:     SortedValues = lists:sort(fun(Val, Val2) ->
                                        nodelist:succ_ord_id(Val, Val2, BaseKey)
                                end, Values),
      Result = lists:map(fun(Value) -> {Value, 1} end, SortedValues),
      ?equals(histogram_rt:get_data(H2), Result),
      true.
  
  add_keys(_Config) ->
  
negative.code:     _ = unittest_helper:end_per_suite(Config),
      ok.
  
  -define(EPSILON, 0.1).
  
  -spec prop_add_keys(BaseKey::?RT:key(), Size::1..50, Values::[?RT:key(),...]) -> true.
  prop_add_keys(BaseKey, Size, Values0) ->
      H = histogram_rt:create(Size, BaseKey),
  