anchor.diff:      
       let boolGen = Gen.elements ["true"; "false"]
       let nullGen = Gen.constant "null"
  +    let numGen  = Arb.generate<decimal>
  +                  |> Gen.map (fun d -> d.ToString(System.Globalization.CultureInfo.InvariantCulture))
   
       let recordGen record =
           record
  
positive.code: open NUnit.Framework
  open System
  open FSharp.Data
  open FsUnit
  open FsCheck
  
  #if INTERACTIVE
  Runner.init.Force()
  #endif
  
  let escaped = Set(['t';'r';'b';'n';'f';'\\';'/';'"'])
  
  let rec isValidJsonString s = 
      match s with
  
negative.code:         let jsonValue = JsonValue.Parse s
          jsonValue.ToString(JsonSaveOptions.DisableFormatting) = s
      let jsonStringArb = Arb.fromGen (jsonStringGen)
      
      Check.One ({Config.QuickThrowOnFailure with MaxTest = 10000},
                (Prop.forAll jsonStringArb stringifyParsed))