anchor.diff:  
   -spec unittest_create_lease(?RT:key()) -> lease_t().
   unittest_create_lease(Id) ->
  +    ?ASSERT(util:is_unittest()), % may only be used in unit-tests
       #lease{id      = Id,
              epoch   = 1,
              owner   = comm:this(),
  
positive.code: on({l_on_cseq, unittest_update_reply,
      {qwrite_deny, _ReqId, _Round, _Value, {content_check_failed, _Reason}},
      Old, New, _Mode, Caller}, State) ->
     comm:send_local(Caller, {l_on_cseq, unittest_update_failed, Old, New}),
     State;
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  
negative.code: on({l_on_cseq, unittest_update,
      Old = #lease{id=Id, epoch=OldEpoch,version=OldVersion},
      New, Mode, Caller}, State) ->
      ?ASSERT(util:is_unittest()), % may only be used in unit-tests
      %% io:format("renew ~p~n", [Old]),
      ContentCheck = is_valid_update(OldEpoch, OldVersion),
      DB = get_db_for_id(Id),
  