anchor.diff:  [options="header"]
   |======
   | Name              | Required  | Default                | Description
  -| `script`          | yes       | -                      | The script to execute
  +| `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.
   |======
  
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: 
  ===== Painless test context
  
  The `painless_test` context executes scripts as is and does not add any special parameters.
  The only variable that is available is `params`, which can be used to access user defined values.
  The result of the script is always converted to a string.
  If no context is specified then this context is used by default.
  