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use futures::channel::mpsc;
use futures::executor::block_on;
use futures::future::{self, Future};
use futures::sink::SinkExt;
use futures::stream::{self, StreamExt};
use futures::task::Poll;
use futures::FutureExt;
use futures_test::task::noop_context;
#[test]
fn select() {
fn select_and_compare(a: Vec<u32>, b: Vec<u32>, expected: Vec<u32>) {
let a = stream::iter(a);
let b = stream::iter(b);
let vec = block_on(stream::select(a, b).collect::<Vec<_>>());
assert_eq!(vec, expected);
}
select_and_compare(vec![1, 2, 3], vec![4, 5, 6], vec![1, 4, 2, 5, 3, 6]);
select_and_compare(vec![1, 2, 3], vec![4, 5], vec![1, 4, 2, 5, 3]);
select_and_compare(vec![1, 2], vec![4, 5, 6], vec![1, 4, 2, 5, 6]);
}
#[test]
fn flat_map() {
block_on(async {
let st =
stream::iter(vec![stream::iter(0..=4u8), stream::iter(6..=10), stream::iter(0..=2)]);
let values: Vec<_> =
st.flat_map(|s| s.filter(|v| futures::future::ready(v % 2 == 0))).collect().await;
assert_eq!(values, vec![0, 2, 4, 6, 8, 10, 0, 2]);
});
}
#[test]
fn scan() {
block_on(async {
let values = stream::iter(vec![1u8, 2, 3, 4, 6, 8, 2])
.scan(1, |state, e| {
*state += 1;
futures::future::ready(if e < *state { Some(e) } else { None })
})
.collect::<Vec<_>>()
.await;
assert_eq!(values, vec![1u8, 2, 3, 4]);
});
}
#[test]
fn take_until() {
fn make_stop_fut(stop_on: u32) -> impl Future<Output = ()> {
let mut i = 0;
future::poll_fn(move |_cx| {
i += 1;
if i <= stop_on {
Poll::Pending
} else {
Poll::Ready(())
}
})
}
block_on(async {
// Verify stopping works:
let stream = stream::iter(1u32..=10);
let stop_fut = make_stop_fut(5);
let stream = stream.take_until(stop_fut);
let last = stream.fold(0, |_, i| async move { i }).await;
assert_eq!(last, 5);
// Verify take_future() works:
let stream = stream::iter(1..=10);
let stop_fut = make_stop_fut(5);
let mut stream = stream.take_until(stop_fut);
assert_eq!(stream.next().await, Some(1));
assert_eq!(stream.next().await, Some(2));
stream.take_future();
let last = stream.fold(0, |_, i| async move { i }).await;
assert_eq!(last, 10);
// Verify take_future() returns None if stream is stopped:
let stream = stream::iter(1u32..=10);
let stop_fut = make_stop_fut(1);
let mut stream = stream.take_until(stop_fut);
assert_eq!(stream.next().await, Some(1));
assert_eq!(stream.next().await, None);
assert!(stream.take_future().is_none());
// Verify TakeUntil is fused:
let mut i = 0;
let stream = stream::poll_fn(move |_cx| {
i += 1;
match i {
1 => Poll::Ready(Some(1)),
2 => Poll::Ready(None),
_ => panic!("TakeUntil not fused"),
}
});
let stop_fut = make_stop_fut(1);
let mut stream = stream.take_until(stop_fut);
assert_eq!(stream.next().await, Some(1));
assert_eq!(stream.next().await, None);
assert_eq!(stream.next().await, None);
});
}
#[test]
#[should_panic]
fn chunks_panic_on_cap_zero() {
let (_, rx1) = mpsc::channel::<()>(1);
let _ = rx1.chunks(0);
}
#[test]
#[should_panic]
fn ready_chunks_panic_on_cap_zero() {
let (_, rx1) = mpsc::channel::<()>(1);
let _ = rx1.ready_chunks(0);
}
#[test]
fn ready_chunks() {
let (mut tx, rx1) = mpsc::channel::<i32>(16);
let mut s = rx1.ready_chunks(2);
let mut cx = noop_context();
assert!(s.next().poll_unpin(&mut cx).is_pending());
block_on(async {
tx.send(1).await.unwrap();
assert_eq!(s.next().await.unwrap(), vec![1]);
tx.send(2).await.unwrap();
tx.send(3).await.unwrap();
tx.send(4).await.unwrap();
assert_eq!(s.next().await.unwrap(), vec![2, 3]);
assert_eq!(s.next().await.unwrap(), vec![4]);
});
}
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