anchor.diff:      "metric": {
         "precision": {
           "relevant_rating_threshold": 1,              <1>
  -        "ignore_unlabeled": "false"                  <2>
  +        "ignore_unlabeled": false                    <2>
         }
      }
   }
   --------------------------------
   // CONSOLE
  +// TEST[setup:twitter]
   
   <1> For graded relevance ratings only ratings above this threshold are
   considered as relevant results for the given query. By default this is set to 1.
  
positive.code: }
  --------------------------------
  // CONSOLE
  
  === Normalized discounted cumulative gain
  
  
negative.code: 
  [source,js]
  --------------------------------
  GET /twitter/tweet/_rank_eval
  {
      "requests": [
      {
  