1 files changed, 326 insertions, 0 deletions
diff --git a/third_party/rust/tokio/tests/time_pause.rs b/third_party/rust/tokio/tests/time_pause.rs
new file mode 100644
index 0000000000..02e050a2dc
--- /dev/null
+++ b/third_party/rust/tokio/tests/time_pause.rs
@@ -0,0 +1,326 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
+use rand::SeedableRng;
+use rand::{rngs::StdRng, Rng};
+use tokio::time::{self, Duration, Instant, Sleep};
+use tokio_test::{assert_elapsed, assert_err, assert_pending, assert_ready, assert_ready_eq, task};
+
+use std::{
+    future::Future,
+    pin::Pin,
+    task::{Context, Poll},
+};
+
+#[tokio::test]
+async fn pause_time_in_main() {
+    tokio::time::pause();
+}
+
+#[tokio::test]
+async fn pause_time_in_task() {
+    let t = tokio::spawn(async {
+        tokio::time::pause();
+    });
+
+    t.await.unwrap();
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+#[should_panic]
+async fn pause_time_in_main_threads() {
+    tokio::time::pause();
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+async fn pause_time_in_spawn_threads() {
+    let t = tokio::spawn(async {
+        tokio::time::pause();
+    });
+
+    assert_err!(t.await);
+}
+
+#[test]
+fn paused_time_is_deterministic() {
+    let run_1 = paused_time_stress_run();
+    let run_2 = paused_time_stress_run();
+
+    assert_eq!(run_1, run_2);
+}
+
+#[tokio::main(flavor = "current_thread", start_paused = true)]
+async fn paused_time_stress_run() -> Vec<Duration> {
+    let mut rng = StdRng::seed_from_u64(1);
+
+    let mut times = vec![];
+    let start = Instant::now();
+    for _ in 0..10_000 {
+        let sleep = rng.gen_range(Duration::from_secs(0)..Duration::from_secs(1));
+        time::sleep(sleep).await;
+        times.push(start.elapsed());
+    }
+
+    times
+}
+
+#[tokio::test(start_paused = true)]
+async fn advance_after_poll() {
+    time::sleep(ms(1)).await;
+
+    let start = Instant::now();
+
+    let mut sleep = task::spawn(time::sleep_until(start + ms(300)));
+
+    assert_pending!(sleep.poll());
+
+    let before = Instant::now();
+    time::advance(ms(100)).await;
+    assert_elapsed!(before, ms(100));
+
+    assert_pending!(sleep.poll());
+}
+
+#[tokio::test(start_paused = true)]
+async fn sleep_no_poll() {
+    let start = Instant::now();
+
+    // TODO: Skip this
+    time::advance(ms(1)).await;
+
+    let mut sleep = task::spawn(time::sleep_until(start + ms(300)));
+
+    let before = Instant::now();
+    time::advance(ms(100)).await;
+    assert_elapsed!(before, ms(100));
+
+    assert_pending!(sleep.poll());
+}
+
+enum State {
+    Begin,
+    AwaitingAdvance(Pin<Box<dyn Future<Output = ()>>>),
+    AfterAdvance,
+}
+
+struct Tester {
+    sleep: Pin<Box<Sleep>>,
+    state: State,
+    before: Option<Instant>,
+    poll: bool,
+}
+
+impl Future for Tester {
+    type Output = ();
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        match &mut self.state {
+            State::Begin => {
+                if self.poll {
+                    assert_pending!(self.sleep.as_mut().poll(cx));
+                }
+                self.before = Some(Instant::now());
+                let advance_fut = Box::pin(time::advance(ms(100)));
+                self.state = State::AwaitingAdvance(advance_fut);
+                self.poll(cx)
+            }
+            State::AwaitingAdvance(ref mut advance_fut) => match advance_fut.as_mut().poll(cx) {
+                Poll::Pending => Poll::Pending,
+                Poll::Ready(()) => {
+                    self.state = State::AfterAdvance;
+                    self.poll(cx)
+                }
+            },
+            State::AfterAdvance => {
+                assert_elapsed!(self.before.unwrap(), ms(100));
+
+                assert_pending!(self.sleep.as_mut().poll(cx));
+
+                Poll::Ready(())
+            }
+        }
+    }
+}
+
+#[tokio::test(start_paused = true)]
+async fn sleep_same_task() {
+    let start = Instant::now();
+
+    // TODO: Skip this
+    time::advance(ms(1)).await;
+
+    let sleep = Box::pin(time::sleep_until(start + ms(300)));
+
+    Tester {
+        sleep,
+        state: State::Begin,
+        before: None,
+        poll: true,
+    }
+    .await;
+}
+
+#[tokio::test(start_paused = true)]
+async fn sleep_same_task_no_poll() {
+    let start = Instant::now();
+
+    // TODO: Skip this
+    time::advance(ms(1)).await;
+
+    let sleep = Box::pin(time::sleep_until(start + ms(300)));
+
+    Tester {
+        sleep,
+        state: State::Begin,
+        before: None,
+        poll: false,
+    }
+    .await;
+}
+
+#[tokio::test(start_paused = true)]
+async fn interval() {
+    let start = Instant::now();
+
+    // TODO: Skip this
+    time::advance(ms(1)).await;
+
+    let mut i = task::spawn(time::interval_at(start, ms(300)));
+
+    assert_ready_eq!(poll_next(&mut i), start);
+    assert_pending!(poll_next(&mut i));
+
+    let before = Instant::now();
+    time::advance(ms(100)).await;
+    assert_elapsed!(before, ms(100));
+    assert_pending!(poll_next(&mut i));
+
+    let before = Instant::now();
+    time::advance(ms(200)).await;
+    assert_elapsed!(before, ms(200));
+    assert_ready_eq!(poll_next(&mut i), start + ms(300));
+    assert_pending!(poll_next(&mut i));
+
+    let before = Instant::now();
+    time::advance(ms(400)).await;
+    assert_elapsed!(before, ms(400));
+    assert_ready_eq!(poll_next(&mut i), start + ms(600));
+    assert_pending!(poll_next(&mut i));
+
+    let before = Instant::now();
+    time::advance(ms(500)).await;
+    assert_elapsed!(before, ms(500));
+    assert_ready_eq!(poll_next(&mut i), start + ms(900));
+    assert_ready_eq!(poll_next(&mut i), start + ms(1200));
+    assert_pending!(poll_next(&mut i));
+}
+
+#[tokio::test(start_paused = true)]
+async fn test_time_advance_sub_ms() {
+    let now = Instant::now();
+
+    let dur = Duration::from_micros(51_592);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+
+    let now = Instant::now();
+    let dur = Duration::from_micros(1);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+}
+
+#[tokio::test(start_paused = true)]
+async fn test_time_advance_3ms_and_change() {
+    let now = Instant::now();
+
+    let dur = Duration::from_micros(3_141_592);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+
+    let now = Instant::now();
+    let dur = Duration::from_micros(3_123_456);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+}
+
+#[tokio::test(start_paused = true)]
+async fn regression_3710_with_submillis_advance() {
+    let start = Instant::now();
+
+    time::advance(Duration::from_millis(1)).await;
+
+    let mut sleep = task::spawn(time::sleep_until(start + Duration::from_secs(60)));
+
+    assert_pending!(sleep.poll());
+
+    let before = Instant::now();
+    let dur = Duration::from_micros(51_592);
+    time::advance(dur).await;
+    assert_eq!(before.elapsed(), dur);
+
+    assert_pending!(sleep.poll());
+}
+
+#[tokio::test(start_paused = true)]
+async fn exact_1ms_advance() {
+    let now = Instant::now();
+
+    let dur = Duration::from_millis(1);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+
+    let now = Instant::now();
+    let dur = Duration::from_millis(1);
+    time::advance(dur).await;
+
+    assert_eq!(now.elapsed(), dur);
+}
+
+#[tokio::test(start_paused = true)]
+async fn advance_once_with_timer() {
+    let mut sleep = task::spawn(time::sleep(Duration::from_millis(1)));
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(250)).await;
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(1500)).await;
+
+    assert!(sleep.is_woken());
+    assert_ready!(sleep.poll());
+}
+
+#[tokio::test(start_paused = true)]
+async fn advance_multi_with_timer() {
+    // Round to the nearest ms
+    // time::sleep(Duration::from_millis(1)).await;
+
+    let mut sleep = task::spawn(time::sleep(Duration::from_millis(1)));
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(250)).await;
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(250)).await;
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(250)).await;
+    assert_pending!(sleep.poll());
+
+    time::advance(Duration::from_micros(250)).await;
+    assert!(sleep.is_woken());
+    assert_ready!(sleep.poll());
+}
+
+fn poll_next(interval: &mut task::Spawn<time::Interval>) -> Poll<Instant> {
+    interval.enter(|cx, mut interval| interval.poll_tick(cx))
+}
+
+fn ms(n: u64) -> Duration {
+    Duration::from_millis(n)
+}