anchor.diff:      Foo1 = {ok, #doc{revs = {1, [<<"foo">>]}}},
       Foo2 = {ok, #doc{revs = {2, [<<"foo2">>, <<"foo">>]}}},
       Bar1 = {ok, #doc{revs = {1, [<<"bar">>]}}},
  +
  +    % an empty worker response does not count as meeting quorum
  +    ?assertMatch(
  +        {ok, #state{}},
  +        handle_message({ok, []}, nil, State0)
  +    ),
  +
       ?assertMatch(
           {ok, #state{}},
           handle_message({ok, [Foo1, Bar1]}, nil, State0)
  
positive.code: skip(#state{revs=Revs} = State) ->
      handle_message({ok, [error || _Rev <- Revs]}, nil, State).
  
  maybe_reply(DbName, ReplyDict, IsComplete, RepairDocs, R) ->
      case lists:all(fun({_, C}) -> C >= R end, ReplyDict) of
      true ->
  
negative.code:         All0, RawReplies),
      Reduced = remove_ancestors(All, []),
      Complete = (ReplyCount =:= (WorkerCount - 1)),
      QuorumMet = lists:all(fun({_, C}) -> C >= R end, Reduced),
      case Reduced of All when QuorumMet andalso ReplyCount =:= (R-1) ->
          Repair = false;
      _ ->
          Repair = [D || {{ok,D}, _} <- Reduced]
      end,
      case maybe_reply(DbName, Reduced, Complete, Repair, R) of
      noreply ->
  