Source code
Revision control
Copy as Markdown
Other Tools
#![cfg(feature = "macros")]
#![allow(clippy::disallowed_names)]
use std::sync::Arc;
#[cfg(tokio_wasm_not_wasi)]
#[cfg(target_pointer_width = "64")]
use wasm_bindgen_test::wasm_bindgen_test as test;
#[cfg(tokio_wasm_not_wasi)]
use wasm_bindgen_test::wasm_bindgen_test as maybe_tokio_test;
#[cfg(not(tokio_wasm_not_wasi))]
use tokio::test as maybe_tokio_test;
use tokio::sync::{oneshot, Semaphore};
use tokio_test::{assert_pending, assert_ready, task};
#[maybe_tokio_test]
async fn sync_one_lit_expr_comma() {
let foo = tokio::join!(async { 1 },);
assert_eq!(foo, (1,));
}
#[maybe_tokio_test]
async fn sync_one_lit_expr_no_comma() {
let foo = tokio::join!(async { 1 });
assert_eq!(foo, (1,));
}
#[maybe_tokio_test]
async fn sync_two_lit_expr_comma() {
let foo = tokio::join!(async { 1 }, async { 2 },);
assert_eq!(foo, (1, 2));
}
#[maybe_tokio_test]
async fn sync_two_lit_expr_no_comma() {
let foo = tokio::join!(async { 1 }, async { 2 });
assert_eq!(foo, (1, 2));
}
#[maybe_tokio_test]
async fn two_await() {
let (tx1, rx1) = oneshot::channel::<&str>();
let (tx2, rx2) = oneshot::channel::<u32>();
let mut join = task::spawn(async {
tokio::join!(async { rx1.await.unwrap() }, async { rx2.await.unwrap() })
});
assert_pending!(join.poll());
tx2.send(123).unwrap();
assert!(join.is_woken());
assert_pending!(join.poll());
tx1.send("hello").unwrap();
assert!(join.is_woken());
let res = assert_ready!(join.poll());
assert_eq!(("hello", 123), res);
}
#[test]
#[cfg(target_pointer_width = "64")]
fn join_size() {
use futures::future;
use std::mem;
let fut = async {
let ready = future::ready(0i32);
tokio::join!(ready)
};
assert_eq!(mem::size_of_val(&fut), 32);
let fut = async {
let ready1 = future::ready(0i32);
let ready2 = future::ready(0i32);
tokio::join!(ready1, ready2)
};
assert_eq!(mem::size_of_val(&fut), 40);
}
async fn non_cooperative_task(permits: Arc<Semaphore>) -> usize {
let mut exceeded_budget = 0;
for _ in 0..5 {
// Another task should run after this task uses its whole budget
for _ in 0..128 {
let _permit = permits.clone().acquire_owned().await.unwrap();
}
exceeded_budget += 1;
}
exceeded_budget
}
async fn poor_little_task(permits: Arc<Semaphore>) -> usize {
let mut how_many_times_i_got_to_run = 0;
for _ in 0..5 {
let _permit = permits.clone().acquire_owned().await.unwrap();
how_many_times_i_got_to_run += 1;
}
how_many_times_i_got_to_run
}
#[tokio::test]
async fn join_does_not_allow_tasks_to_starve() {
let permits = Arc::new(Semaphore::new(1));
// non_cooperative_task should yield after its budget is exceeded and then poor_little_task should run.
let (non_cooperative_result, little_task_result) = tokio::join!(
non_cooperative_task(Arc::clone(&permits)),
poor_little_task(permits)
);
assert_eq!(5, non_cooperative_result);
assert_eq!(5, little_task_result);
}
#[tokio::test]
async fn a_different_future_is_polled_first_every_time_poll_fn_is_polled() {
let poll_order = Arc::new(std::sync::Mutex::new(vec![]));
let fut = |x, poll_order: Arc<std::sync::Mutex<Vec<i32>>>| async move {
for _ in 0..4 {
{
let mut guard = poll_order.lock().unwrap();
guard.push(x);
}
tokio::task::yield_now().await;
}
};
tokio::join!(
fut(1, Arc::clone(&poll_order)),
fut(2, Arc::clone(&poll_order)),
fut(3, Arc::clone(&poll_order)),
);
// Each time the future created by join! is polled, it should start
// by polling a different future first.
assert_eq!(
vec![1, 2, 3, 2, 3, 1, 3, 1, 2, 1, 2, 3],
*poll_order.lock().unwrap()
);
}
#[tokio::test]
#[allow(clippy::unit_cmp)]
async fn empty_join() {
assert_eq!(tokio::join!(), ());
}