public void DistinctUntilChanged_ArgumentChecking()
{
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int>(null));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int>(null, EqualityComparer <int> .Default));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int>(DummySubscribable <int> .Instance, null));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int, int>(null, _ => _));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int, int>(DummySubscribable <int> .Instance, null));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int, int>(DummySubscribable <int> .Instance, _ => _, null));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int, int>(null, _ => _, EqualityComparer <int> .Default));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.DistinctUntilChanged <int, int>(DummySubscribable <int> .Instance, null, EqualityComparer <int> .Default));
}