How to execute F# unittest code with F# interpreter (fsharpi)?

I have this F# unit test code (testit.fsx) from http://ift.tt/1lHkOEP

#r @"/Users/smcho/Dropbox/smcho/bin/mono/NUnit.2.6.4/nunit.framework.dll"
open NUnit.Framework

[<TestFixture>]
type TestClass() = 

    [<Test>]
    member this.When2IsAddedTo2Expect4() = 
        Assert.AreEqual(4, 2+2)

I'm trying to run the test with fsharpi, but when I executed fsharpi testit.fsx I get no output.

I use Mono on Mac OS X.