1 files changed, 463 insertions, 0 deletions
diff --git a/third_party/rust/futures/tests/stream.rs b/third_party/rust/futures/tests/stream.rs
new file mode 100644
index 0000000000..5cde45833f
--- /dev/null
+++ b/third_party/rust/futures/tests/stream.rs
@@ -0,0 +1,463 @@
+use std::cell::Cell;
+use std::iter;
+use std::pin::Pin;
+use std::rc::Rc;
+use std::sync::Arc;
+use std::task::Context;
+
+use futures::channel::mpsc;
+use futures::executor::block_on;
+use futures::future::{self, Future};
+use futures::lock::Mutex;
+use futures::sink::SinkExt;
+use futures::stream::{self, StreamExt};
+use futures::task::Poll;
+use futures::{ready, FutureExt};
+use futures_core::Stream;
+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 flatten_unordered() {
+    use futures::executor::block_on;
+    use futures::stream::*;
+    use futures::task::*;
+    use std::convert::identity;
+    use std::pin::Pin;
+    use std::thread;
+    use std::time::Duration;
+
+    struct DataStream {
+        data: Vec<u8>,
+        polled: bool,
+        wake_immediately: bool,
+    }
+
+    impl Stream for DataStream {
+        type Item = u8;
+
+        fn poll_next(mut self: Pin<&mut Self>, ctx: &mut Context) -> Poll<Option<Self::Item>> {
+            if !self.polled {
+                if !self.wake_immediately {
+                    let waker = ctx.waker().clone();
+                    let sleep_time =
+                        Duration::from_millis(*self.data.first().unwrap_or(&0) as u64 / 10);
+                    thread::spawn(move || {
+                        thread::sleep(sleep_time);
+                        waker.wake_by_ref();
+                    });
+                } else {
+                    ctx.waker().wake_by_ref();
+                }
+                self.polled = true;
+                Poll::Pending
+            } else {
+                self.polled = false;
+                Poll::Ready(self.data.pop())
+            }
+        }
+    }
+
+    struct Interchanger {
+        polled: bool,
+        base: u8,
+        wake_immediately: bool,
+    }
+
+    impl Stream for Interchanger {
+        type Item = DataStream;
+
+        fn poll_next(mut self: Pin<&mut Self>, ctx: &mut Context) -> Poll<Option<Self::Item>> {
+            if !self.polled {
+                self.polled = true;
+                if !self.wake_immediately {
+                    let waker = ctx.waker().clone();
+                    let sleep_time = Duration::from_millis(self.base as u64);
+                    thread::spawn(move || {
+                        thread::sleep(sleep_time);
+                        waker.wake_by_ref();
+                    });
+                } else {
+                    ctx.waker().wake_by_ref();
+                }
+                Poll::Pending
+            } else {
+                let data: Vec<_> = (0..6).rev().map(|v| v + self.base * 6).collect();
+                self.base += 1;
+                self.polled = false;
+                Poll::Ready(Some(DataStream {
+                    polled: false,
+                    data,
+                    wake_immediately: self.wake_immediately && self.base % 2 == 0,
+                }))
+            }
+        }
+    }
+
+    // basic behaviour
+    {
+        block_on(async {
+            let st = stream::iter(vec![
+                stream::iter(0..=4u8),
+                stream::iter(6..=10),
+                stream::iter(10..=12),
+            ]);
+
+            let fl_unordered = st.flatten_unordered(3).collect::<Vec<_>>().await;
+
+            assert_eq!(fl_unordered, vec![0, 6, 10, 1, 7, 11, 2, 8, 12, 3, 9, 4, 10]);
+        });
+
+        block_on(async {
+            let st = stream::iter(vec![
+                stream::iter(0..=4u8),
+                stream::iter(6..=10),
+                stream::iter(0..=2),
+            ]);
+
+            let mut fm_unordered = st
+                .flat_map_unordered(1, |s| s.filter(|v| futures::future::ready(v % 2 == 0)))
+                .collect::<Vec<_>>()
+                .await;
+
+            fm_unordered.sort_unstable();
+
+            assert_eq!(fm_unordered, vec![0, 0, 2, 2, 4, 6, 8, 10]);
+        });
+    }
+
+    // wake up immediately
+    {
+        block_on(async {
+            let mut fl_unordered = Interchanger { polled: false, base: 0, wake_immediately: true }
+                .take(10)
+                .map(|s| s.map(identity))
+                .flatten_unordered(10)
+                .collect::<Vec<_>>()
+                .await;
+
+            fl_unordered.sort_unstable();
+
+            assert_eq!(fl_unordered, (0..60).collect::<Vec<u8>>());
+        });
+
+        block_on(async {
+            let mut fm_unordered = Interchanger { polled: false, base: 0, wake_immediately: true }
+                .take(10)
+                .flat_map_unordered(10, |s| s.map(identity))
+                .collect::<Vec<_>>()
+                .await;
+
+            fm_unordered.sort_unstable();
+
+            assert_eq!(fm_unordered, (0..60).collect::<Vec<u8>>());
+        });
+    }
+
+    // wake up after delay
+    {
+        block_on(async {
+            let mut fl_unordered = Interchanger { polled: false, base: 0, wake_immediately: false }
+                .take(10)
+                .map(|s| s.map(identity))
+                .flatten_unordered(10)
+                .collect::<Vec<_>>()
+                .await;
+
+            fl_unordered.sort_unstable();
+
+            assert_eq!(fl_unordered, (0..60).collect::<Vec<u8>>());
+        });
+
+        block_on(async {
+            let mut fm_unordered = Interchanger { polled: false, base: 0, wake_immediately: false }
+                .take(10)
+                .flat_map_unordered(10, |s| s.map(identity))
+                .collect::<Vec<_>>()
+                .await;
+
+            fm_unordered.sort_unstable();
+
+            assert_eq!(fm_unordered, (0..60).collect::<Vec<u8>>());
+        });
+
+        block_on(async {
+            let (mut fm_unordered, mut fl_unordered) = futures_util::join!(
+                Interchanger { polled: false, base: 0, wake_immediately: false }
+                    .take(10)
+                    .flat_map_unordered(10, |s| s.map(identity))
+                    .collect::<Vec<_>>(),
+                Interchanger { polled: false, base: 0, wake_immediately: false }
+                    .take(10)
+                    .map(|s| s.map(identity))
+                    .flatten_unordered(10)
+                    .collect::<Vec<_>>()
+            );
+
+            fm_unordered.sort_unstable();
+            fl_unordered.sort_unstable();
+
+            assert_eq!(fm_unordered, fl_unordered);
+            assert_eq!(fm_unordered, (0..60).collect::<Vec<u8>>());
+        });
+    }
+
+    // waker panics
+    {
+        let stream = Arc::new(Mutex::new(
+            Interchanger { polled: false, base: 0, wake_immediately: true }
+                .take(10)
+                .flat_map_unordered(10, |s| s.map(identity)),
+        ));
+
+        struct PanicWaker;
+
+        impl ArcWake for PanicWaker {
+            fn wake_by_ref(_arc_self: &Arc<Self>) {
+                panic!("WAKE UP");
+            }
+        }
+
+        std::thread::spawn({
+            let stream = stream.clone();
+            move || {
+                let mut st = poll_fn(|cx| {
+                    let mut lock = ready!(stream.lock().poll_unpin(cx));
+
+                    let panic_waker = waker(Arc::new(PanicWaker));
+                    let mut panic_cx = Context::from_waker(&panic_waker);
+                    let _ = ready!(lock.poll_next_unpin(&mut panic_cx));
+
+                    Poll::Ready(Some(()))
+                });
+
+                block_on(st.next())
+            }
+        })
+        .join()
+        .unwrap_err();
+
+        block_on(async move {
+            let mut values: Vec<_> = stream.lock().await.by_ref().collect().await;
+            values.sort_unstable();
+
+            assert_eq!(values, (0..60).collect::<Vec<u8>>());
+        });
+    }
+
+    // stream panics
+    {
+        let st = stream::iter(iter::once(
+            once(Box::pin(async { panic!("Polled") })).left_stream::<DataStream>(),
+        ))
+        .chain(
+            Interchanger { polled: false, base: 0, wake_immediately: true }
+                .map(|stream| stream.right_stream())
+                .take(10),
+        );
+
+        let stream = Arc::new(Mutex::new(st.flatten_unordered(10)));
+
+        std::thread::spawn({
+            let stream = stream.clone();
+            move || {
+                let mut st = poll_fn(|cx| {
+                    let mut lock = ready!(stream.lock().poll_unpin(cx));
+                    let data = ready!(lock.poll_next_unpin(cx));
+
+                    Poll::Ready(data)
+                });
+
+                block_on(st.next())
+            }
+        })
+        .join()
+        .unwrap_err();
+
+        block_on(async move {
+            let mut values: Vec<_> = stream.lock().await.by_ref().collect().await;
+            values.sort_unstable();
+
+            assert_eq!(values, (0..60).collect::<Vec<u8>>());
+        });
+    }
+}
+
+#[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]);
+    });
+}
+
+struct SlowStream {
+    times_should_poll: usize,
+    times_polled: Rc<Cell<usize>>,
+}
+impl Stream for SlowStream {
+    type Item = usize;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.times_polled.set(self.times_polled.get() + 1);
+        if self.times_polled.get() % 2 == 0 {
+            cx.waker().wake_by_ref();
+            return Poll::Pending;
+        }
+        if self.times_polled.get() >= self.times_should_poll {
+            return Poll::Ready(None);
+        }
+        Poll::Ready(Some(self.times_polled.get()))
+    }
+}
+
+#[test]
+fn select_with_strategy_doesnt_terminate_early() {
+    for side in [stream::PollNext::Left, stream::PollNext::Right] {
+        let times_should_poll = 10;
+        let count = Rc::new(Cell::new(0));
+        let b = stream::iter([10, 20]);
+
+        let mut selected = stream::select_with_strategy(
+            SlowStream { times_should_poll, times_polled: count.clone() },
+            b,
+            |_: &mut ()| side,
+        );
+        block_on(async move { while selected.next().await.is_some() {} });
+        assert_eq!(count.get(), times_should_poll + 1);
+    }
+}