anchor.diff:      if !resultStr <> 20 then Assert.Fail()   
           
       // empty vector    
  -    let emptyArr : vector<int> = [| |]
  +    let emptyArr : vector<int> = vector [| |]
       let resultEpt = ref 0
       Vector.Parallel.iter funInt emptyArr 
       if !resultEpt <> 0 then Assert.Fail()    
   
       // null vector
  -    let nullArr = null : string[]  
  +    let nullArr = Unchecked.defaultof<vector<_>> : vector<string>  
       checkThrowsArgumentNullException (fun () -> Vector.Parallel.iter funStr nullArr |> ignore)  
           
       ()
  
positive.code: [<TestCase>]
  let ``Parallel.iteri`` () : unit =   
      // integer vector
      let intArr = [| 1..10 |] 
                   
      let resultInt = ref 0    
      let funInt (x:int) y =   
  
negative.code: [<TestCase>]
  let tryPick () : unit =
      // integer vector
      let intArr = vector [| 1..10 |]    
      let funcInt x = 
              match x with
              | _ when x % 3 = 0 -> Some (x.ToString())            
  