public void A_Intersperse_must_inject_element_between_existing_elements_when_downstream_is_aggregate()
{
var concated =
Source.From(new[] { 1, 2, 3 })
.Select(x => x.ToString())
.Intersperse(",")
.RunAggregate("", (s, s1) => s + s1, Materializer);
concated.Wait(TimeSpan.FromSeconds(3)).Should().BeTrue();
concated.Result.Should().Be("1,2,3");
}