1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
//! Test time/sleep implementations that work by manually advancing time with a `tick()`
//!
//! # Examples
//!
//! Spawning a task that creates new sleep tasks and waits for them sequentially,
//! and advancing passed all of them with a single call to `tick()`.
//!
//! ```rust,no_run
//! use std::time::{Duration, SystemTime};
//! use aws_smithy_async::test_util::tick_advance_sleep::tick_advance_time_and_sleep;
//! use aws_smithy_async::time::TimeSource;
//! use aws_smithy_async::rt::sleep::AsyncSleep;
//!
//! # async fn example() {
//! // Create the test time/sleep implementations.
//! // They will start at SystemTime::UNIX_EPOCH.
//! let (time, sleep) = tick_advance_time_and_sleep();
//!
//! // Spawn the task that sequentially sleeps
//! let task = tokio::spawn(async move {
//! sleep.sleep(Duration::from_secs(1)).await;
//! sleep.sleep(Duration::from_secs(2)).await;
//! sleep.sleep(Duration::from_secs(3)).await;
//! });
//! // Verify that task hasn't done anything yet since we haven't called `tick`
//! tokio::task::yield_now().await;
//! assert!(!task.is_finished());
//! assert_eq!(SystemTime::UNIX_EPOCH, time.now());
//!
//! // Tick 6 seconds, which is long enough to go passed all the sequential sleeps
//! time.tick(Duration::from_secs(6)).await;
//! assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(6), time.now());
//!
//! // Verify the task joins, indicating all the sleeps are done
//! task.await.unwrap();
//! # }
//! ```
use crate::{
rt::sleep::{AsyncSleep, Sleep},
time::TimeSource,
};
use std::{
future::IntoFuture,
ops::{Deref, DerefMut},
sync::{Arc, Mutex},
time::{Duration, SystemTime},
};
use tokio::sync::oneshot::Sender;
#[derive(Debug)]
struct QueuedSleep {
/// Duration since `UNIX_EPOCH` at which point the sleep is finished.
presents_at: Duration,
notify: Option<Sender<()>>,
}
#[derive(Default, Debug)]
struct Inner {
// Need to use a Vec since VecDeque doesn't have sort functions,
// and BTreeSet doesn't fit since we could have more than one sleep presenting
// at the same time (and there's no way to compare the notify channels).
sleeps: Vec<QueuedSleep>,
/// Duration since `UNIX_EPOCH` that represents "now".
now: Duration,
}
impl Inner {
fn push(&mut self, sleep: QueuedSleep) {
self.sleeps.push(sleep);
self.sleeps.sort_by_key(|s| s.presents_at);
}
fn next_presenting(&mut self, time: Duration) -> Option<QueuedSleep> {
if self
.sleeps
.first()
.map(|f| f.presents_at <= time)
.unwrap_or(false)
{
Some(self.sleeps.remove(0))
} else {
None
}
}
}
#[derive(Clone, Default, Debug)]
struct SharedInner {
inner: Arc<Mutex<Inner>>,
}
impl SharedInner {
fn get(&self) -> impl Deref<Target = Inner> + '_ {
self.inner.lock().unwrap()
}
fn get_mut(&self) -> impl DerefMut<Target = Inner> + '_ {
self.inner.lock().unwrap()
}
}
/// Tick-advancing test sleep implementation.
///
/// See [module docs](crate::test_util::tick_advance_sleep) for more information.
#[derive(Clone, Debug)]
pub struct TickAdvanceSleep {
inner: SharedInner,
}
impl AsyncSleep for TickAdvanceSleep {
fn sleep(&self, duration: Duration) -> Sleep {
// Use a one-shot channel to block the sleep future until `TickAdvanceTime::tick`
// chooses to complete it by sending with the receiver.
let (tx, rx) = tokio::sync::oneshot::channel::<()>();
let mut inner = self.inner.get_mut();
let now = inner.now;
// Add the sleep to the queue, which `TickAdvanceTime` will examine when ticking.
inner.push(QueuedSleep {
presents_at: now + duration,
notify: Some(tx),
});
Sleep::new(async move {
let _ = rx.into_future().await;
})
}
}
/// Tick-advancing test time source implementation.
///
/// See [module docs](crate::test_util::tick_advance_sleep) for more information.
#[derive(Clone, Debug)]
pub struct TickAdvanceTime {
inner: SharedInner,
}
impl TickAdvanceTime {
/// Advance time by `duration`.
///
/// This will yield the async runtime after each sleep that presents between
/// the previous current time and the time after the given duration. This allows
/// for async tasks pending one of those sleeps to do some work and also create
/// additional sleep tasks. Created sleep tasks may also complete during this
/// call to `tick()` if they present before the given time duration.
pub async fn tick(&self, duration: Duration) {
let time = self.inner.get().now + duration;
// Tick to each individual sleep time and yield the runtime so that any
// futures waiting on a sleep run before futures waiting on a later sleep.
//
// We also need to recheck the list of queued sleeps every iteration since
// unblocked tasks could have queued up more sleeps, and these sleeps may also
// need to present before ones that were previously queued.
loop {
// Can't do `while let` since that holds the lock open
let Some(mut presenting) = self.inner.get_mut().next_presenting(time) else {
break;
};
// Make sure the time is always accurate for async code that runs
// after completing the sleep.
self.inner.get_mut().now = presenting.presents_at;
// Notify the sleep, and then yield to let work blocked on that sleep to proceed
let _ = presenting.notify.take().unwrap().send(());
tokio::task::yield_now().await;
}
// Set the final time.
self.inner.get_mut().now = time;
}
}
impl TimeSource for TickAdvanceTime {
fn now(&self) -> SystemTime {
SystemTime::UNIX_EPOCH + self.inner.get().now
}
}
/// Creates tick-advancing test time/sleep implementations.
///
/// See [module docs](crate::test_util::tick_advance_sleep) for more information.
pub fn tick_advance_time_and_sleep() -> (TickAdvanceTime, TickAdvanceSleep) {
let inner = SharedInner::default();
(
TickAdvanceTime {
inner: inner.clone(),
},
TickAdvanceSleep {
inner: inner.clone(),
},
)
}
#[cfg(test)]
mod tests {
use super::*;
use futures_util::FutureExt;
#[tokio::test]
async fn tick_advances() {
let (time, sleep) = tick_advance_time_and_sleep();
assert_eq!(SystemTime::UNIX_EPOCH, time.now());
time.tick(Duration::from_secs(1)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(1), time.now());
let sleeps = vec![
tokio::spawn(sleep.sleep(Duration::from_millis(500))),
tokio::spawn(sleep.sleep(Duration::from_secs(1))),
tokio::spawn(sleep.sleep(Duration::from_secs(2))),
tokio::spawn(sleep.sleep(Duration::from_secs(3))),
tokio::spawn(sleep.sleep(Duration::from_secs(4))),
];
tokio::task::yield_now().await;
for sleep in &sleeps {
assert!(!sleep.is_finished());
}
time.tick(Duration::from_secs(1)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(2), time.now());
assert!(sleeps[0].is_finished());
assert!(sleeps[1].is_finished());
assert!(!sleeps[2].is_finished());
assert!(!sleeps[3].is_finished());
assert!(!sleeps[4].is_finished());
time.tick(Duration::from_secs(2)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(4), time.now());
assert!(sleeps[2].is_finished());
assert!(sleeps[3].is_finished());
assert!(!sleeps[4].is_finished());
time.tick(Duration::from_secs(1)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(5), time.now());
assert!(sleeps[4].is_finished());
}
#[tokio::test]
async fn sleep_leading_to_sleep() {
let (time, sleep) = tick_advance_time_and_sleep();
let task = tokio::spawn(async move {
sleep.sleep(Duration::from_secs(1)).await;
sleep.sleep(Duration::from_secs(2)).await;
sleep.sleep(Duration::from_secs(3)).await;
});
tokio::task::yield_now().await;
assert!(!task.is_finished());
assert_eq!(SystemTime::UNIX_EPOCH, time.now());
time.tick(Duration::from_secs(6)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(6), time.now());
task.await.unwrap();
}
#[tokio::test]
async fn racing_sleeps() {
let (time, sleep) = tick_advance_time_and_sleep();
let task = tokio::spawn(async move {
let sleep1 = sleep.sleep(Duration::from_secs(1)).then({
let sleep = sleep.clone();
move |_| async move {
sleep.sleep(Duration::from_secs(1)).await;
}
});
let sleep2 = sleep.sleep(Duration::from_secs(3));
tokio::select! {
_ = sleep1 => { /* good */}
_ = sleep2 => { panic!("sleep2 should not complete before sleep1") }
}
});
tokio::task::yield_now().await;
assert!(!task.is_finished());
assert_eq!(SystemTime::UNIX_EPOCH, time.now());
time.tick(Duration::from_secs(6)).await;
assert_eq!(SystemTime::UNIX_EPOCH + Duration::from_secs(6), time.now());
task.await.unwrap();
}
}