dioxus/packages/core/tests/task.rs

//! Verify that tasks get polled by the virtualdom properly, and that we escape wait_for_work safely

use std::{sync::atomic::AtomicUsize, time::Duration};

use dioxus::prelude::*;
use dioxus_core::{generation, needs_update, spawn_forever};

async fn run_vdom(app: fn() -> Element) {
    let mut dom = VirtualDom::new(app);

    dom.rebuild(&mut dioxus_core::NoOpMutations);

    tokio::select! {
        _ = dom.wait_for_work() => {}
        _ = tokio::time::sleep(Duration::from_millis(500)) => {}
    };
}

#[tokio::test]
async fn running_async() {
    static POLL_COUNT: AtomicUsize = AtomicUsize::new(0);

    fn app() -> Element {
        use_hook(|| {
            spawn(async {
                for x in 0..10 {
                    tokio::time::sleep(Duration::from_micros(50)).await;
                    POLL_COUNT.fetch_add(x, std::sync::atomic::Ordering::Relaxed);
                }
            });

            spawn(async {
                for x in 0..10 {
                    tokio::time::sleep(Duration::from_micros(25)).await;
                    POLL_COUNT.fetch_add(x * 2, std::sync::atomic::Ordering::Relaxed);
                }
            });
        });

        rsx!({})
    }

    run_vdom(app).await;

    // By the time the tasks are finished, we should've accumulated ticks from two tasks
    // Be warned that by setting the delay to too short, tokio might not schedule in the tasks
    assert_eq!(
        POLL_COUNT.fetch_add(0, std::sync::atomic::Ordering::Relaxed),
        135
    );
}

#[tokio::test]
async fn spawn_forever_persists() {
    use std::sync::atomic::Ordering;
    static POLL_COUNT: AtomicUsize = AtomicUsize::new(0);

    fn app() -> Element {
        if generation() > 0 {
            rsx!(div {})
        } else {
            needs_update();
            rsx!(Child {})
        }
    }

    #[component]
    fn Child() -> Element {
        spawn_forever(async move {
            for _ in 0..10 {
                POLL_COUNT.fetch_add(1, Ordering::Relaxed);
                tokio::time::sleep(Duration::from_millis(50)).await;
            }
        });

        rsx!(div {})
    }

    let mut dom = VirtualDom::new(app);

    dom.rebuild(&mut dioxus_core::NoOpMutations);
    dom.render_immediate(&mut dioxus_core::NoOpMutations);

    tokio::select! {
        _ = dom.wait_for_work() => {}
        // We intentionally wait a bit longer than 50ms*10 to make sure the test has time to finish
        // Without the extra time, the test can fail on windows
        _ = tokio::time::sleep(Duration::from_millis(1000)) => {}
    };

    // By the time the tasks are finished, we should've accumulated ticks from two tasks
    // Be warned that by setting the delay to too short, tokio might not schedule in the tasks
    assert_eq!(POLL_COUNT.load(Ordering::Relaxed), 10);
}

/// Prove that yield_now doesn't cause a deadlock
#[tokio::test]
async fn yield_now_works() {
    thread_local! {
        static SEQUENCE: std::cell::RefCell<Vec<usize>> = const { std::cell::RefCell::new(Vec::new()) };
    }

    fn app() -> Element {
        // these two tasks should yield to eachother
        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    tokio::task::yield_now().await;
                    SEQUENCE.with(|s| s.borrow_mut().push(1));
                }
            })
        });

        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    tokio::task::yield_now().await;
                    SEQUENCE.with(|s| s.borrow_mut().push(2));
                }
            })
        });

        rsx!({})
    }

    run_vdom(app).await;

    SEQUENCE.with(|s| assert_eq!(s.borrow().len(), 20));
}