anchor.diff:  %% @todo Fix the types! It should be:
   %-spec is_smaller(commit_time(), commit_time()) -> boolean.
   is_smaller({OpDc1, OpCommitTime1}, {OpDc2, OpCommitTime2}) ->
  -  (OpDc1 /= OpDc2) or (OpCommitTime1 < OpCommitTime2).
  +    (OpDc1 /= OpDc2) or (OpCommitTime1 < OpCommitTime2).
   
   %% @doc Apply updates in given order without any checks.
   %%    Careful: In contrast to materialize/6, it takes just operations, not clocksi_payloads!
  
positive.code:   InSnapshot = OpCommitTime =< Ts,
    case SnapshotCommitTime of
      ignore -> 
      	InSnapshot;
      {_SnapshotDc, _SnapshotCT} ->
  		    	InSnapshot andalso is_smaller(SnapshotCommitTime, OperationCommitTime)
  	end.
  
  %% @doc Checks whether a commit time is smaller than another one.
  
negative.code:     {ok, PNCounter2, CommitTime2} = materialize(crdt_pncounter,
                                        PNCounter, ignore,
                                        vectorclock:from_list([{2,2},{1,2}]),
                                        Ops, ignore),
      ?assertEqual({4, {2,1}}, {crdt_pncounter:value(PNCounter2), CommitTime2}),
      
      
  