anchor.diff:  
   [<TestCase>]
   let average () : unit =   
  -      
       // empty float32 vector
       let emptyFloatArray = Vector.empty<float32> 
       checkThrowsArgumentException(fun () -> Vector.average emptyFloatArray |> ignore)
  
positive.code: [<TestCase>]
  let tryPick () : unit =
      // integer vector
      let intArr = [| 1..10 |]    
      let funcInt x = 
              match x with
              | _ when x % 3 = 0 -> Some (x.ToString())            
  
negative.code: [<TestCase>]
  let find () : unit =
      // integer vector
      let intArr = vector [| 1..20 |]
      let funcInt x = if (x%5 = 0) then true else false
      let resultInt = Vector.find funcInt intArr
      if resultInt <> 5 then Assert.Fail()
          
      // string vector
      let strArr = vector [|"Lists"; "are"; "a"; "commonly"; "data";"structor" |]
      let funcStr (x:string) = if (x.Length >7) then true else false
      let resultStr = Vector.find funcStr strArr
      if resultStr <> "commonly" then Assert.Fail()
          
      // empty vector
      let emptyArr:vector<int> = vector [| |] 
      checkThrowsKeyNotFoundException (fun () -> Vector.find (fun x -> true) emptyArr |> ignore)        
  
      // null vector
      let nullArr :vector<string> = Unchecked.defaultof<vector<_>>
      checkThrowsArgumentNullException (fun () -> Vector.find funcStr nullArr |> ignore) 
          
      () 
  