anchor.diff:      /// factorial
       let rec fact n =
           match n with
  -        | 0 -> 1
  +        | _ when n <= 0 -> 1
           | _ -> n * fact (n - 1)
   
       /// fibonacci
  
positive.code:             | _ -> loop (a + b) a (c - 1)
          loop 1 0 n
  
      ///reverse list funciton
      let reverse list =
          let rec loop list revList =
              match list with
  
negative.code: 
      [<Test>]
      let ``factorialTest`` () = (fact 5) |> should equal 120
  
      [<Test>]
      let ``fibonacciTest`` () = (fib 5) |> should equal 5
  
      [<Test>]
      let ``reverseListTest`` () = (reverse [1; 2; 3]) |> should equal [3; 2; 1]
  
      [<Test>]
      let ``listMakerTest`` () = (listMaker 2 3) |> should equal [4; 8; 16; 32]