public void A_Limit_must_produce_empty_sequence_when_source_is_empty_and_n_is_equal_to_zero()
{
var input = Enumerable.Empty<int>().ToList();
var n = input.Count;
var future = Source.Empty<int>()
.Limit(n)
.Grouped(1000)
.RunWith(Sink.FirstOrDefault<IEnumerable<int>>(), Materializer);
future.Wait(TimeSpan.FromMilliseconds(300)).Should().BeTrue();
future.Result.Should().BeNull();
}