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