use std::time::Duration;

use tokio::time::sleep;

mod support;
use support::{assert_tasks, spawn_named, ExpectedTask};

/// This test asserts the behavior that was fixed in #440. Before that fix,
/// the polls of a child were also counted towards the parent (the task which
/// spawned the child task). In this scenario, that would result in the parent
/// having 3 polls counted, when it should really be 1.
#[test]
// The child task is polled explicitly to control its execution.
// As a result, the clippy warning is ignored.
#[allow(clippy::async_yields_async)]
fn child_polls_dont_count_towards_parent_polls() {
    // There is an extra poll because the span enters one more time upon drop (see
    // tokio-rs/tracing#2562).
    let expected_tasks = vec![
        ExpectedTask::default()
            .match_name("parent".into())
            .expect_polls(2),
        ExpectedTask::default()
            .match_name("child".into())
            .expect_polls(3),
    ];

    let future = async {
        let child_join_handle = spawn_named("parent", async {
            spawn_named("child", async {
                sleep(Duration::ZERO).await;
            })
        })
        .await
        .expect("joining parent failed");

        child_join_handle.await.expect("joining child failed");
    };

    assert_tasks(expected_tasks, future);
}