anchor.diff:  tests_avail() ->
       %% [test_sane_result].
       [test_sane_result,
  -     test_join].
  -    %%  test_leave].
  +     test_join,
  +     test_leave].
   
   init_per_suite(Config) ->
       unittest_helper:init_per_suite(Config).
  
positive.code: 
  add_data() ->
      Data = [{"1", "MapReduce allows for distributed processing of the map and reduction operations."}
              , {"2", "Provided each mapping operation can run independently, all maps may be performed in parallel."}
              , {"3", "This example data set contains one single word only once."}
              , {"4", "Now I am too lazy to construct another sentence that actually makes sense."}
             ],
      [api_tx:write(Key, {Key, Value}) || {Key, Value} <- Data],
      ok.
  
negative.code:     ok.
  
  test_leave(_Config) ->
      ?proto_sched(start),
      api_vm:shutdown_nodes(1),
      {[AddedNode], _} = api_vm:add_nodes(1),
      unittest_helper:wait_for_stable_ring(),
      unittest_helper:check_ring_size_fully_joined(2),
      Pids = pid_groups:find_all(dht_node),
      ct:pal("setting breakpoint before starting reduce phase on ~p", [Pids]),
      NextPhase = fun(Msg, State) ->
              case Msg of
                  {mr, next_phase, JobId, 1, _Interval} ->
                      comm:send_local(self(), Msg),
                      drop_single;
                  _ ->
                      false
              end
      end,
      [gen_component:bp_set_cond(Pid, NextPhase, mr_bp) || Pid <- Pids],
      ct:pal("starting job that triggers breakpoint"),
      MrPid = spawn_link(fun() ->
                      ct:pal("starting mr job"),
                      Res = api_mr:start_job(get_wc_job_erl()),
                      ct:pal("mr job finished"),
                      check_results(Res)
              end),
      timer:sleep(1000),
      ct:pal("shutting down node to provoke slide"),
      ok = api_vm:shutdown_node(AddedNode),
      [ct:pal("removing breakpoints on ~p...~p", [Pid, gen_component:bp_del_async(Pid, mr_bp)]) || Pid <- Pids],
      util:wait_for_process_to_die(MrPid),
      ok.
  
  get_wc_job_erl() ->
  