public void SequenceEqual_ArgumentChecking()
{
var ns = default(ISubscribable <int>);
var xs = DummySubscribable <int> .Instance;
var nc = default(IEqualityComparer <int>);
var ic = EqualityComparer <int> .Default;
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SequenceEqual(ns, xs));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SequenceEqual(xs, ns));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SequenceEqual(ns, xs, ic));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SequenceEqual(xs, ns, ic));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.SequenceEqual(xs, xs, nc));
}