It is amazing how hard functional programming is for an average csharp guy, and yet how easy it is to express logic in this language.

open NUnit.Framework
let equal arg1 arg2 =
    arg1 = arg2
let should f x y =
    let c = f x
    Assert.IsTrue(c y)
let ``two plus two should equal four`` =
    1 + 1 |> should equal 2

The above code is inspired by the awesome FsUnit project.