public void PartialSortByWithNullSequence() { Assert.ThrowsArgumentNullException("source", () => MoreEnumerable.PartialSortBy <object, object>(null, 0, e => e)); Assert.ThrowsArgumentNullException("source", () => MoreEnumerable.PartialSortBy <object, object>(null, 0, e => e, Comparer <object> .Default)); }