anchor.diff:          reverse -> lists:seq(MsgNum - 1, 0, -1);
           random -> utils:random_shuffle(lists:seq(0, MsgNum - 1))
       end,
  +
  +    initializer:remove_pending_messages(),
  +    {ok, SessId} = session_setup(Worker),
   
       % Send 'MsgNum' messages in 'MsgOrd' order.
       {_, SendUs, SendTime, SendUnit} = utils:duration(fun() ->
  
positive.code:     test_node_starter:clean_environment(Config).
  
  init_per_testcase(_, Config) ->
      [Worker | _] = Workers = ?config(op_worker_nodes, Config),
      initializer:remove_pending_messages(),
      mock_router(Workers),
      mock_communicator(Workers),
      {ok, SessId} = session_setup(Worker),
      [{session_id, SessId} | Config].
  
  end_per_testcase(_, Config) ->
      [Worker | _] = Workers = ?config(op_worker_nodes, Config),
      SessId = ?config(session_id, Config),
      session_teardown(Worker, SessId),
      test_utils:mock_validate_and_unload(Workers, [communicator, router]).
  
  %%%===================================================================
  
negative.code:     ]}
  ]).
  route_message_should_work_for_multiple_streams(Config) ->
      [Worker | _] = Workers = ?config(op_worker_nodes, Config),
      MsgNum = ?config(msg_num, Config),
      StmNum = ?config(stm_num, Config),
  
      Msgs = [#message_stream{sequence_number = SeqNum} ||
          SeqNum <- lists:seq(0, MsgNum - 1)],
      RevSeqNums = lists:seq(MsgNum - 1, 0, -1),
  
      initializer:remove_pending_messages(),
      {ok, SessId} = session_setup(Worker),
  
      % Production of 'MsgNum' messages in random order belonging to 'StmsCount'
      % streams. Requests are routed through random workers.
  