anchor.diff:  
   document:: Contains the document that will be temporarily indexed in-memory and is accessible from the script.
   index:: The name of an index containing a mapping that is compatible with the document being indexed.
  -query:: If `_score` is used in the script then a query can specified that will be used to compute a score.
  +query:: If `_score` is used in the script then a query can specify that it will be used to compute a score.
   
   *Example*
   
  
positive.code: ===== Filter context
  
  The `filter` context executes scripts as if they were executed inside a `script` query.
  For testing purposes a document must be provided that will be indexed temporarily in-memory and
  is accessible to the script being tested. Because of this the _source, stored fields and doc values
  are available in the script being tested.
  
  The following parameters may be specified in `context_setup` for a filter context:
  
  
negative.code: [options="header"]
  |======
  | Name              | Required  | Default                | Description
  | `script`          | yes       | -                      | The script to execute.
  | `context`         | no        | `painless_test`        | The context the script should be executed in.
  | `context_setup`   | no        | -                      | Additional parameters to the context.
  |======
  