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use tokio_stream::{self as stream, Stream, StreamExt};
use tokio_test::task;
use tokio_test::{assert_pending, assert_ready};
mod support {
pub(crate) mod mpsc;
}
use support::mpsc;
#[tokio::test]
async fn merge_sync_streams() {
let mut s = stream::iter(vec![0, 2, 4, 6]).merge(stream::iter(vec![1, 3, 5]));
for i in 0..7 {
let rem = 7 - i;
assert_eq!(s.size_hint(), (rem, Some(rem)));
assert_eq!(Some(i), s.next().await);
}
assert!(s.next().await.is_none());
}
#[tokio::test]
async fn merge_async_streams() {
let (tx1, rx1) = mpsc::unbounded_channel_stream();
let (tx2, rx2) = mpsc::unbounded_channel_stream();
let mut rx = task::spawn(rx1.merge(rx2));
assert_eq!(rx.size_hint(), (0, None));
assert_pending!(rx.poll_next());
tx1.send(1).unwrap();
assert!(rx.is_woken());
assert_eq!(Some(1), assert_ready!(rx.poll_next()));
assert_pending!(rx.poll_next());
tx2.send(2).unwrap();
assert!(rx.is_woken());
assert_eq!(Some(2), assert_ready!(rx.poll_next()));
assert_pending!(rx.poll_next());
drop(tx1);
assert!(rx.is_woken());
assert_pending!(rx.poll_next());
tx2.send(3).unwrap();
assert!(rx.is_woken());
assert_eq!(Some(3), assert_ready!(rx.poll_next()));
assert_pending!(rx.poll_next());
drop(tx2);
assert!(rx.is_woken());
assert_eq!(None, assert_ready!(rx.poll_next()));
}
#[test]
fn size_overflow() {
struct Monster;
impl tokio_stream::Stream for Monster {
type Item = ();
fn poll_next(
self: std::pin::Pin<&mut Self>,
_cx: &mut std::task::Context<'_>,
) -> std::task::Poll<Option<()>> {
panic!()
}
fn size_hint(&self) -> (usize, Option<usize>) {
(usize::MAX, Some(usize::MAX))
}
}
let m1 = Monster;
let m2 = Monster;
let m = m1.merge(m2);
assert_eq!(m.size_hint(), (usize::MAX, None));
}
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