anchor.diff:      ?equals_w_note(Value, ["WriteB", "WriteA"], "Values must match exactly due to interleaving").
   
   test_read_write_commuting(_Config) ->
  +    %% Write tuple {A,B} on every replica. Update second element to C for
  +    %% 3 out of 4 replicas. Read first element and make sure the outdated replica
  +    %% is included. Since operations commute, no write-through should have been
  +    %% triggered.
       Key = "123",
   
       % write baseline
  
positive.code:                                 fun ?MODULE:cc_noop/3,
                                  fun ?MODULE:wf_second/3}, "C"),
  
      PrbrDataBeforeRead = prbr_data(),
      _ = slow_link(4, kv_db, 1, dht_node),
      {ok, "A"} = read_via_node(4, Key, fun ?MODULE:rf_first/1),
      PrbrDataAfterRead = prbr_data(),
      ?equals_w_note(PrbrDataBeforeRead, PrbrDataAfterRead,
                     "Read was independent from write and thus should not have caused a "
                     "write through"),
      ok.
  
negative.code: %% @copyright 2013-2018 Zuse Institute Berlin
  %   Licensed under the Apache License, Version 2.0 (the "License");
  %   you may not use this file except in compliance with the License.
  %   You may obtain a copy of the License at
  