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#![cfg(feature = "sync")]
use tokio::sync::watch;
use tokio_stream::wrappers::WatchStream;
use tokio_stream::StreamExt;
use tokio_test::assert_pending;
use tokio_test::task::spawn;
#[tokio::test]
async fn watch_stream_message_not_twice() {
let (tx, rx) = watch::channel("hello");
let mut counter = 0;
let mut stream = WatchStream::new(rx).map(move |payload| {
println!("{}", payload);
if payload == "goodbye" {
counter += 1;
}
if counter >= 2 {
panic!("too many goodbyes");
}
});
let task = tokio::spawn(async move { while stream.next().await.is_some() {} });
// Send goodbye just once
tx.send("goodbye").unwrap();
drop(tx);
task.await.unwrap();
}
#[tokio::test]
async fn watch_stream_from_rx() {
let (tx, rx) = watch::channel("hello");
let mut stream = WatchStream::from(rx);
assert_eq!(stream.next().await.unwrap(), "hello");
tx.send("bye").unwrap();
assert_eq!(stream.next().await.unwrap(), "bye");
}
#[tokio::test]
async fn watch_stream_from_changes() {
let (tx, rx) = watch::channel("hello");
let mut stream = WatchStream::from_changes(rx);
assert_pending!(spawn(&mut stream).poll_next());
tx.send("bye").unwrap();
assert_eq!(stream.next().await.unwrap(), "bye");
}