public void SkipUntil_ArgumentChecking()
{
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SkipUntil <int, int>(null, DummySubscribable <int> .Instance));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SkipUntil <int, int>(DummySubscribable <int> .Instance, null));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SkipUntil(default(ISubscribable <int>), DateTimeOffset.Now));
}