anchor.diff:     ?_assertEqual(false, RResult4)].
   
   test_undefined_value(_) ->
  -  prometheus_summary:new([{name, orders_summary}, {labels, [department]}, {help, "Track orders count/total sum"}]),
  +  prometheus_summary:new([{name, orders_summary},
  +                          {labels, [department]},
  +                          {help, "Track orders count/total sum"}]),
     Value = prometheus_summary:value(orders_summary, [electronics]),
     [?_assertEqual(undefined, Value)].
  
positive.code:    ?_assertEqual({0, 0}, RValue)].
  
  
  test_double(_) ->
    prometheus_summary:new([{name, orders_summary}, {labels, [department]}, {help, "Track orders count/total sum"}]),
    prometheus_summary:dobserve(orders_summary, [electronics], 1.5),
    prometheus_summary:dobserve(orders_summary, [electronics], 2.7),
    timer:sleep(10), %% dobserve is async so lets make sure gen_server processed our increment request
    Value = prometheus_summary:value(orders_summary, [electronics]),
    prometheus_summary:reset(orders_summary, [electronics]),
    RValue = prometheus_summary:value(orders_summary, [electronics]),
  
negative.code:    fun prometheus_eunit_common:stop/1,
     [fun test_registration/1,
      fun test_errors/1,
      fun test_observe/1,
      fun test_dobserve/1,
      fun test_observe_duration/1,
      fun test_remove/1,
      fun test_undefined_value/1]}.
  