anchor.diff:  %% first call `generate_downstream/3', to get the downstream version of the
   %% operation, and then call `update/2'.
   %%
  -%% It provides two operations: insert, which adds an element to the RGA, and delete,
  +%% It provides two operations: addRight, which adds an element to the RGA, and remove,
   %% which removes an element from the RGA.
   %%
   %% This implementation is based on the paper cited below.
  
positive.code:     {ok, L2} = update(DownstreamOp1, L1),
      ?assertMatch([{ok, 1, _}, {ok, 2, _}], L2).
  
  %% In the tests that follow, the values of generate_downstream are placed by hand so
  %% the intended scenarios can be correctly tested, not depending on the unique() function.
  
  insert_in_the_middle_test() ->
  
negative.code:     ?assertMatch([{ok, 1, _}, {ok, 3, _}], L5).
  
  %% This test creates two RGAs and performs updates, checking they reach
  %% the same final state after the four updates are aplied in both replicas.
  concurrent_updates_in_two_replicas_test() ->
      R1_0 = new(),
      R2_0 = new(),
  