anchor.diff:  [source,console]
   ----
   PUT my-index
  +{
     "mappings": {
       "properties": {
         "my-agg-metric-field": {
           "type": "aggregate_metric_double",
  -        "metrics": [ "min", "max", "sum", "value_count"],
  +        "metrics": [ "min", "max", "sum", "value_count" ],
           "default_metric": "max"
         }
       }
     }
   }
   ----
  -// TEST[skip:awaiting fix]
   
   [[aggregate-metric-double-params]]
   ==== Parameters for `aggregate_metric_double` fields
  
positive.code: Default metric sub-field to use for queries, scripts, and aggregations that
  don't use a sub-field. Must be a value from the `metrics` array.
  
  
  [[aggregate-metric-double-uses]]
  ==== Uses
  
  
negative.code:     }
    }
  }
  ----
  // TEST[continued]
  
  The search returns the following hit. The value of the `default_metric` field,
  `max`, matches the query value.
  
  [source,console-result]
  ----
  {
    ...
      "hits": {
      "total": {
        "value": 1,
        "relation": "eq"
      },
      "max_score": 1.0,
      "hits": [
        {
          "_index": "stats-index",
          "_id": "1",
          "_score": 1.0,
          "_source": {
            "agg_metric": {
              "min": -302.5,
              "max": 702.3,
              "sum": 200.0,
              "value_count": 25
            }
          }
        }
      ]
    }
  }
  ----
  // TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,/]
  