public void Expand_ArgumentChecking() { ReactiveAssert.Throws <ArgumentNullException>(() => ObservableEx.Expand(null, DummyFunc <int, IObservable <int> > .Instance, DummyScheduler.Instance)); ReactiveAssert.Throws <ArgumentNullException>(() => ObservableEx.Expand(DummyObservable <int> .Instance, null, DummyScheduler.Instance)); ReactiveAssert.Throws <ArgumentNullException>(() => ObservableEx.Expand(DummyObservable <int> .Instance, DummyFunc <int, IObservable <int> > .Instance, null)); ReactiveAssert.Throws <ArgumentNullException>(() => ObservableEx.Expand(null, DummyFunc <int, IObservable <int> > .Instance)); ReactiveAssert.Throws <ArgumentNullException>(() => ObservableEx.Expand(DummyObservable <int> .Instance, null)); }