FizzBuzz in F# (work in progress)

fizzbuzz.fs

module FizzBuzzFSharp.``FizzBuzz in F#``

open NUnit.Framework
open FsUnit

let fizzbuzz n =
    match n with
    | n when n % 15 = 0 -> "fizzbuzz"
    | n when n % 5 = 0 -> "buzz"
    | n when n % 3 = 0 -> "fizz"
    | n -> n.ToString()

[<TestFixture>]
type ``Given A Number When Fizzing`` ()=

    [<TestCase(1, "1")>]
    [<TestCase(2, "2")>]
    [<TestCase(4, "4")>]
    [<TestCase(7, "7")>] member x.
     ``when not multiple or 3 or 5 then the number is returned`` input output =
            fizzbuzz input |> should equal output

    [<TestCase(3)>]
    [<TestCase(6)>]
    [<TestCase(9)>]
    [<TestCase(12)>] member x.
     ``when multiple of 3 and not 5 then fizz`` (input)=
            fizzbuzz input |> should equal "fizz"

    [<TestCase(5)>]
    [<TestCase(10)>]
    [<TestCase(20)>] member x.
     ``when multiple of 5 and not 3 then buzz`` input =
            fizzbuzz input |> should equal "buzz"

    [<TestCase(15)>]
    [<TestCase(30)>]
    [<TestCase(45)>] member x.
     ``when multiple of 15 then fizzbuzz`` input =
            fizzbuzz input |> should equal "fizzbuzz"

Please delete this.