anchor.diff:                       |> warn
                        <| ()
                    | false -> ok())
  -            let stringOut = stringOut.ToString().Trim() //stringOut has a newline at the end.
  +            let stringOut = stringOut.ToString()
               output.Write(stringOut)
               do! (match expected with
                    | Some x -> 
  
positive.code:                                  fun s -> 
                                       if File.Exists(s) then 
                                           File.ReadAllText(s, Encoding.ASCII)
                                               .Trim()
                                           |> Some
                                           |> ok
                                       else None |> warn (FileNotExist(s)))
  
negative.code:         | InvalidArguments -> sprintf "Usage: %s" (parser.PrintUsage())
          | ParseError(x, _) -> x
          | TestFailure(expected, found) -> 
              if expected.Length + found.Length < DisplayExpectenFoundTreshold * 2 then 
                  sprintf 
                      "Program output is expected to be\n\t%s\n but it was \n\t%s" 
                      expected found
              else 
                  "Program output is different than the expected, but it is not shown, because of its size."
          | UnexpectedEndOfInput -> "Unexpected end of input."
      
      [<EntryPoint>]
  