use super::*;use futures::{    FutureExt,    channel::{mpsc, oneshot},    executor::block_on,    future,    sink::SinkExt,    stream::{FuturesUnordered, StreamExt},};use std::{    cell::RefCell,    collections::{BTreeSet, HashSet},    pin::Pin,    rc::Rc,    sync::Arc,    task::{Context, Poll, Waker},}; #[test]fn test_foreground_executor_spawn() {    let result = TestScheduler::once(async |scheduler| {        let task = scheduler.foreground().spawn(async move { 42 });        task.await    });    assert_eq!(result, 42);} #[test]fn test_background_executor_spawn() {    TestScheduler::once(async |scheduler| {        let task = scheduler.background().spawn(async move { 42 });        let result = task.await;        assert_eq!(result, 42);    });} #[test]fn test_scheduler_drops_with_stalled_detached_foreground_task() {    let scheduler = Arc::new(TestScheduler::new(TestSchedulerConfig::default()));    let weak_scheduler = Arc::downgrade(&scheduler);    let (sender, receiver) = oneshot::channel::<()>();     scheduler        .foreground()        .spawn(async move {            receiver.await.ok();        })        .detach();    scheduler.run();     drop(scheduler);    assert!(weak_scheduler.upgrade().is_none());    drop(sender);} #[test]fn test_scheduler_drops_with_stalled_detached_background_task() {    let scheduler = Arc::new(TestScheduler::new(TestSchedulerConfig::default()));    let weak_scheduler = Arc::downgrade(&scheduler);    let (sender, receiver) = oneshot::channel::<()>();     scheduler        .background()        .spawn(async move {            receiver.await.ok();        })        .detach();    scheduler.run();     drop(scheduler);    assert!(weak_scheduler.upgrade().is_none());    drop(sender);} /// A dedicated task that is never polled must not keep the scheduler alive:/// its runnable sits in the scheduler's own queue, so any strong scheduler/// handle captured by the future would form a reference cycle and leak both.#[test]fn test_scheduler_drops_with_never_polled_dedicated_task() {    let scheduler = Arc::new(TestScheduler::new(TestSchedulerConfig::default()));    let weak_scheduler = Arc::downgrade(&scheduler);     scheduler        .background()        .spawn_dedicated(|_executor| async move {})        .detach();     drop(scheduler);    assert!(weak_scheduler.upgrade().is_none());} #[test]fn test_foreground_ordering() {    let mut traces = HashSet::new();     TestScheduler::many(if cfg!(miri) { 5 } else { 100 }, async |scheduler| {        #[derive(Hash, PartialEq, Eq)]        struct TraceEntry {            session: usize,            task: usize,        }         let trace = Rc::new(RefCell::new(Vec::new()));         let foreground_1 = scheduler.foreground();        for task in 0..10 {            foreground_1                .spawn({                    let trace = trace.clone();                    async move {                        trace.borrow_mut().push(TraceEntry { session: 0, task });                    }                })                .detach();        }         let foreground_2 = scheduler.foreground();        for task in 0..10 {            foreground_2                .spawn({                    let trace = trace.clone();                    async move {                        trace.borrow_mut().push(TraceEntry { session: 1, task });                    }                })                .detach();        }         scheduler.run();         assert_eq!(            trace                .borrow()                .iter()                .filter(|entry| entry.session == 0)                .map(|entry| entry.task)                .collect::<Vec<_>>(),            (0..10).collect::<Vec<_>>()        );        assert_eq!(            trace                .borrow()                .iter()                .filter(|entry| entry.session == 1)                .map(|entry| entry.task)                .collect::<Vec<_>>(),            (0..10).collect::<Vec<_>>()        );         traces.insert(trace.take());    });     assert!(traces.len() > 1, "Expected at least two traces");} #[test]fn test_timer_ordering() {    TestScheduler::many(1, async |scheduler| {        let background = scheduler.background();        let futures = FuturesUnordered::new();        futures.push(            async {                background.timer(Duration::from_millis(100)).await;                2            }            .boxed(),        );        futures.push(            async {                background.timer(Duration::from_millis(50)).await;                1            }            .boxed(),        );        futures.push(            async {                background.timer(Duration::from_millis(150)).await;                3            }            .boxed(),        );        assert_eq!(futures.collect::<Vec<_>>().await, vec![1, 2, 3]);    });} #[test]fn test_foreground_task_can_hold_mut_borrow_across_await() {    TestScheduler::once(async |scheduler| {        let foreground = scheduler.foreground();        let (sender, mut receiver) = mpsc::unbounded::<()>();         foreground            .spawn(async move {                receiver.next().await;            })            .detach();         scheduler.run();        sender.unbounded_send(()).unwrap();        scheduler.run();    });} #[test]fn test_send_from_bg_to_fg() {    TestScheduler::once(async |scheduler| {        let foreground = scheduler.foreground();        let background = scheduler.background();         let (sender, receiver) = oneshot::channel::<i32>();         background            .spawn(async move {                sender.send(42).unwrap();            })            .detach();         let task = foreground.spawn(async move { receiver.await.unwrap() });        let result = task.await;        assert_eq!(result, 42);    });} #[test]fn test_randomize_order() {    // Test deterministic mode: different seeds should produce same execution order    let mut deterministic_results = HashSet::new();    for seed in 0..10 {        let config = TestSchedulerConfig {            seed,            randomize_order: false,            ..Default::default()        };        let order = block_on(capture_execution_order(config));        assert_eq!(order.len(), 6);        deterministic_results.insert(order);    }     // All deterministic runs should produce the same result    assert_eq!(        deterministic_results.len(),        1,        "Deterministic mode should always produce same execution order"    );     // Test randomized mode: different seeds can produce different execution orders    let mut randomized_results = HashSet::new();    for seed in 0..20 {        let config = TestSchedulerConfig::with_seed(seed);        let order = block_on(capture_execution_order(config));        assert_eq!(order.len(), 6);        randomized_results.insert(order);    }     // Randomized mode should produce multiple different execution orders    assert!(        randomized_results.len() > 1,        "Randomized mode should produce multiple different orders"    );} async fn capture_execution_order(config: TestSchedulerConfig) -> Vec<String> {    let scheduler = Arc::new(TestScheduler::new(config));    let foreground = scheduler.foreground();    let background = scheduler.background();     let (sender, receiver) = mpsc::unbounded::<String>();     // Spawn foreground tasks    for i in 0..3 {        let mut sender = sender.clone();        foreground            .spawn(async move {                sender.send(format!("fg-{}", i)).await.ok();            })            .detach();    }     // Spawn background tasks    for i in 0..3 {        let mut sender = sender.clone();        background            .spawn(async move {                sender.send(format!("bg-{}", i)).await.ok();            })            .detach();    }     drop(sender); // Close sender to signal no more messages    scheduler.run();     receiver.collect().await} #[test]fn test_block() {    let scheduler = Arc::new(TestScheduler::new(TestSchedulerConfig::default()));    let (tx, rx) = oneshot::channel();     // Spawn background task to send value    let _ = scheduler        .background()        .spawn(async move {            tx.send(42).unwrap();        })        .detach();     // Block on receiving the value    let result = scheduler.foreground().block_on(async { rx.await.unwrap() });    assert_eq!(result, 42);} #[test]#[should_panic(expected = "Parking forbidden.")]fn test_parking_panics() {    let config = TestSchedulerConfig {        capture_pending_traces: true,        ..Default::default()    };    let scheduler = Arc::new(TestScheduler::new(config));    scheduler.foreground().block_on(async {        let (_tx, rx) = oneshot::channel::<()>();        rx.await.unwrap(); // This will never complete    });} #[test]fn test_block_with_parking() {    let config = TestSchedulerConfig {        allow_parking: true,        ..Default::default()    };    let scheduler = Arc::new(TestScheduler::new(config));    let (tx, rx) = oneshot::channel();     // Spawn background task to send value    let _ = scheduler        .background()        .spawn(async move {            tx.send(42).unwrap();        })        .detach();     // Block on receiving the value (will park if needed)    let result = scheduler.foreground().block_on(async { rx.await.unwrap() });    assert_eq!(result, 42);} #[test]fn test_helper_methods() {    // Test the once method    let result = TestScheduler::once(async |scheduler: Arc<TestScheduler>| {        let background = scheduler.background();        background.spawn(async { 42 }).await    });    assert_eq!(result, 42);     // Test the many method    let results = TestScheduler::many(3, async |scheduler: Arc<TestScheduler>| {        let background = scheduler.background();        background.spawn(async { 10 }).await    });    assert_eq!(results, vec![10, 10, 10]);} #[test]fn test_many_with_arbitrary_seed() {    for seed in [0u64, 1, 5, 42] {        let mut seeds_seen = Vec::new();        let iterations = 3usize;         for current_seed in seed..seed + iterations as u64 {            let scheduler = Arc::new(TestScheduler::new(TestSchedulerConfig::with_seed(                current_seed,            )));            let captured_seed = current_seed;            scheduler                .foreground()                .block_on(async { seeds_seen.push(captured_seed) });            scheduler.run();        }         assert_eq!(            seeds_seen,            (seed..seed + iterations as u64).collect::<Vec<_>>(),            "Expected {iterations} iterations starting at seed {seed}"        );    }} #[test]fn test_block_with_timeout() {    // Test case: future completes within timeout    TestScheduler::once(async |scheduler| {        let foreground = scheduler.foreground();        let future = future::ready(42);        let output = foreground.block_with_timeout(Duration::from_millis(100), future);        assert_eq!(output.ok(), Some(42));    });     // Test case: future times out    TestScheduler::once(async |scheduler| {        // Make timeout behavior deterministic by forcing the timeout tick budget to be exactly 0.        // This prevents `block_with_timeout` from making progress via extra scheduler stepping and        // accidentally completing work that we expect to time out.        scheduler.set_timeout_ticks(0..=0);         let foreground = scheduler.foreground();        let future = future::pending::<()>();        let output = foreground.block_with_timeout(Duration::from_millis(50), future);        assert!(output.is_err(), "future should not have finished");    });     // Test case: future makes progress via timer but still times out    let mut results = BTreeSet::new();    TestScheduler::many(if cfg!(miri) { 5 } else { 100 }, async |scheduler| {        // Keep the existing probabilistic behavior here (do not force 0 ticks), since this subtest        // is explicitly checking that some seeds/timeouts can complete while others can time out.        let task = scheduler.background().spawn(async move {            Yield { polls: 10 }.await;            42        });        let output = scheduler            .foreground()            .block_with_timeout(Duration::from_millis(50), task);        results.insert(output.ok());    });    assert_eq!(        results.into_iter().collect::<Vec<_>>(),        if cfg!(miri) {            vec![Some(42)]        } else {            vec![None, Some(42)]        }    );     // Regression test:    // A timed-out future must not be cancelled. The returned future should still be    // pollable to completion later. We also want to ensure time only advances when we    // explicitly advance it (not by yielding).    TestScheduler::once(async |scheduler| {        // Force immediate timeout: the timeout tick budget is 0 so we will not step or        // advance timers inside `block_with_timeout`.        scheduler.set_timeout_ticks(0..=0);         let background = scheduler.background();         // This task should only complete once time is explicitly advanced.        let task = background.spawn({            let scheduler = scheduler.clone();            async move {                scheduler.timer(Duration::from_millis(100)).await;                123            }        });         // This should time out before we advance time enough for the timer to fire.        let timed_out = scheduler            .foreground()            .block_with_timeout(Duration::from_millis(50), task);        assert!(            timed_out.is_err(),            "expected timeout before advancing the clock enough for the timer"        );         // Now explicitly advance time and ensure the returned future can complete.        let mut task = timed_out.err().unwrap();        scheduler.advance_clock(Duration::from_millis(100));        scheduler.run();         let output = scheduler.foreground().block_on(&mut task);        assert_eq!(output, 123);    });} // When calling block, we shouldn't make progress on foreground-spawned futures with the same session id.#[test]fn test_block_does_not_progress_same_session_foreground() {    let mut task2_made_progress_once = false;    TestScheduler::many(if cfg!(miri) { 5 } else { 1000 }, async |scheduler| {        let foreground1 = scheduler.foreground();        let foreground2 = scheduler.foreground();         let task1 = foreground1.spawn(async move {});        let task2 = foreground2.spawn(async move {});         foreground1.block_on(async {            scheduler.yield_random().await;            assert!(!task1.is_ready());            task2_made_progress_once |= task2.is_ready();        });         task1.await;        task2.await;    });     assert!(        task2_made_progress_once,        "Expected task from different foreground executor to make progress (at least once)"    );

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