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// @trace TEST-ENG-004 [req:REQ-ENG-004] [level:integration]
// P1-A Stage 1 prerequisite validation: prove `bun_event_loop::MiniEventLoop`
// is usable from the bao_runtime crate (same thread, no JS engine). When P1-A
// lands, drain_and_check will use this same API to replace TimerHeap+epoll.
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use bun_event_loop::AnyTaskWithExtraContext::AnyTaskWithExtraContext;
use bun_event_loop::MiniEventLoop::MiniEventLoop;
// Pull in bao_uloop's `#[no_mangle] extern "C"` symbols (uws_get_loop etc.)
// — `MiniEventLoop::init()` reaches them via `UwsLoop::get()` but the linker
// GCs unreferenced no-mangle symbols without an explicit Rust reference.
// Also pull in bun_runtime::dispatch so `__bun_run_file_poll` (extern "Rust")
// is not GC'd — `bun_io::posix_event_loop::FilePoll::on_update` references it
// at link time.
fn force_uloop_link() {
// Product path owns residual/RealImpl (no bao_native_stubs co-link).
bao_uloop::force_link();
// Ensure dispatch module's extern "Rust" symbols survive link-time GC.
// The module is `pub` in bao_runtime, so just referencing it here is enough.
let _ = bun_runtime::dispatch::__bun_run_file_poll
as unsafe extern "Rust" fn(*mut bun_io::posix_event_loop::FilePoll, i64);
}
#[derive(Debug)]
struct CounterCtx {
fired: AtomicUsize,
}
fn increment_task(ctx: *mut CounterCtx, _extra: *mut std::ffi::c_void) {
unsafe {
(*ctx).fired.fetch_add(1, Ordering::SeqCst);
}
}
#[test]
fn test_minimal_event_loop_init() {
force_uloop_link();
let mut loop_ = MiniEventLoop::init();
assert!(
!loop_.loop_ptr().is_null(),
"MiniEventLoop must produce a non-null uSockets loop pointer"
);
assert!(
loop_.tasks.readable_length() == 0,
"fresh loop must have empty task queue"
);
assert!(
!loop_.pipe_read_buffer().is_empty(),
"pipe_read_buffer must be initialized on first access"
);
}
#[test]
fn test_minimal_event_loop_enqueue_and_drain() {
force_uloop_link();
let mut loop_ = MiniEventLoop::init();
let ctx = Box::new(CounterCtx {
fired: AtomicUsize::new(0),
});
let ctx_ptr = Box::into_raw(ctx);
// from_callback_auto_deinit wraps the ctx pointer and self-frees the wrapper
// when the callback fires. counter is bumped inside the callback.
let task_ptr = AnyTaskWithExtraContext::from_callback_auto_deinit(ctx_ptr, increment_task);
assert!(!task_ptr.is_null());
// SAFETY: enqueue_task_concurrent expects a NonNull<AnyTaskWithExtraContext>
// that outlives the queue. The wrapper box is freed inside the callback,
// so ownership transfers to the loop until tick drains it.
let task_nn = unsafe { core::ptr::NonNull::new_unchecked(task_ptr) };
loop_.enqueue_task_concurrent(task_nn);
assert_eq!(
loop_.tasks.readable_length(),
0,
"concurrent queue is not yet flushed into tasks"
);
// tick_once first flushes concurrent → tasks, then runs all tasks.
loop_.tick_once(core::ptr::null_mut());
let fired = unsafe { (*ctx_ptr).fired.load(Ordering::SeqCst) };
assert_eq!(fired, 1, "callback must fire exactly once after tick_once");
// The wrapper Box was freed inside `function<T>` (auto-deinit). Reclaim
// ctx_ptr only — the wrapper memory is already dropped.
unsafe {
drop(Box::from_raw(ctx_ptr));
}
}
#[test]
fn test_minimal_event_loop_tick_until_done() {
force_uloop_link();
let mut loop_ = MiniEventLoop::init();
let done = Arc::new(AtomicBool::new(true));
let done_clone = done.clone();
// is_done returns true immediately — tick must return on first iteration.
// An empty loop with is_done=true must not call into uSockets internals.
loop_.tick(core::ptr::null_mut(), |_ctx| {
done_clone.load(Ordering::SeqCst)
});
assert!(
done.load(Ordering::Relaxed),
"done flag unchanged after tick"
);
}
#[test]
fn test_minimal_event_loop_multiple_ticks() {
force_uloop_link();
let mut loop_ = MiniEventLoop::init();
// tick_once on an empty loop enters epoll_wait which blocks indefinitely.
// Use tick_without_idle instead, which only drains concurrent+task queues
// without entering the OS event loop, making it safe to call on empty loops.
for _ in 0..10 {
loop_.tick_without_idle(core::ptr::null_mut());
}
assert_eq!(loop_.tasks.readable_length(), 0);
}