anchor.diff:              a
               b
               c
  -            hasFoo
  +            d(input : true )
           }
       }"""
   
  
positive.code:     ctx.FieldExecuteMap.SetExecute("Data", fieldDef)
      next ctx
  
  // After the schema has been compiled, inject a fake variable "foo" to every input object
  let postCompileMiddleware (schema : ISchema) (next : ISchema -> unit) =
      schema.TypeMap.ToSeq()
      |> Seq.iter(fun (n, def) ->
                      match def with
                      | InputObject iobj ->
                          iobj.Fields
                          |> Array.iter(fun f -> f.ExecuteInput <- (fun value vars -> f.ExecuteInput value (Map.add "foo" (upcast 1) vars)))
                      | _ -> ())
      next schema
  
  
negative.code:                     upcast NameValueLookup.ofList 
                          [ "a", upcast "Cookie" 
                            "b", upcast "Banana"
                            "d", upcast false ] ]
      match result with
      | Direct (data, errors) ->
          empty errors
  