1 use futures::executor::block_on;
2 use futures::future::{self, BoxFuture, FutureExt};
3 use std::sync::mpsc;
4 use std::thread;
5
6 #[test]
lots()7 fn lots() {
8 #[cfg(not(futures_sanitizer))]
9 const N: i32 = 1_000;
10 #[cfg(futures_sanitizer)] // If N is many, asan reports stack-overflow: https://gist.github.com/taiki-e/099446d21cbec69d4acbacf7a9646136
11 const N: i32 = 100;
12
13 fn do_it(input: (i32, i32)) -> BoxFuture<'static, i32> {
14 let (n, x) = input;
15 if n == 0 {
16 future::ready(x).boxed()
17 } else {
18 future::ready((n - 1, x + n)).then(do_it).boxed()
19 }
20 }
21
22 let (tx, rx) = mpsc::channel();
23 thread::spawn(|| block_on(do_it((N, 0)).map(move |x| tx.send(x).unwrap())));
24 assert_eq!((0..=N).sum::<i32>(), rx.recv().unwrap());
25 }
26