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use crate::sync::semaphore_ll::{Permit, Semaphore};
use tokio_test::task;
use tokio_test::{assert_pending, assert_ready_err, assert_ready_ok};
#[test]
fn available_permits() {
let s = Semaphore::new(100);
assert_eq!(s.available_permits(), 100);
// Polling for a permit succeeds immediately
let mut permit = task::spawn(Permit::new());
assert!(!permit.is_acquired());
assert_ready_ok!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_eq!(s.available_permits(), 99);
assert!(permit.is_acquired());
// Polling again on the same waiter does not claim a new permit
assert_ready_ok!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_eq!(s.available_permits(), 99);
assert!(permit.is_acquired());
}
#[test]
fn unavailable_permits() {
let s = Semaphore::new(1);
let mut permit_1 = task::spawn(Permit::new());
let mut permit_2 = task::spawn(Permit::new());
// Acquire the first permit
assert_ready_ok!(permit_1.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_eq!(s.available_permits(), 0);
permit_2.enter(|cx, mut p| {
// Try to acquire the second permit
assert_pending!(p.poll_acquire(cx, &s));
});
permit_1.release(&s);
assert_eq!(s.available_permits(), 0);
assert!(permit_2.is_woken());
assert_ready_ok!(permit_2.enter(|cx, mut p| p.poll_acquire(cx, &s)));
permit_2.release(&s);
assert_eq!(s.available_permits(), 1);
}
#[test]
fn zero_permits() {
let s = Semaphore::new(0);
assert_eq!(s.available_permits(), 0);
let mut permit = task::spawn(Permit::new());
// Try to acquire the permit
permit.enter(|cx, mut p| {
assert_pending!(p.poll_acquire(cx, &s));
});
s.add_permits(1);
assert!(permit.is_woken());
assert_ready_ok!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
}
#[test]
#[should_panic]
fn validates_max_permits() {
use std::usize;
Semaphore::new((usize::MAX >> 2) + 1);
}
#[test]
fn close_semaphore_prevents_acquire() {
let s = Semaphore::new(1);
s.close();
assert_eq!(1, s.available_permits());
let mut permit = task::spawn(Permit::new());
assert_ready_err!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_eq!(1, s.available_permits());
}
#[test]
fn close_semaphore_notifies_permit1() {
let s = Semaphore::new(0);
let mut permit = task::spawn(Permit::new());
assert_pending!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
s.close();
assert!(permit.is_woken());
assert_ready_err!(permit.enter(|cx, mut p| p.poll_acquire(cx, &s)));
}
#[test]
fn close_semaphore_notifies_permit2() {
let s = Semaphore::new(2);
let mut permit1 = task::spawn(Permit::new());
let mut permit2 = task::spawn(Permit::new());
let mut permit3 = task::spawn(Permit::new());
let mut permit4 = task::spawn(Permit::new());
// Acquire a couple of permits
assert_ready_ok!(permit1.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_ready_ok!(permit2.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_pending!(permit3.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_pending!(permit4.enter(|cx, mut p| p.poll_acquire(cx, &s)));
s.close();
assert!(permit3.is_woken());
assert!(permit4.is_woken());
assert_ready_err!(permit3.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_ready_err!(permit4.enter(|cx, mut p| p.poll_acquire(cx, &s)));
assert_eq!(0, s.available_permits());
permit1.release(&s);
assert_eq!(1, s.available_permits());
assert_ready_err!(permit1.enter(|cx, mut p| p.poll_acquire(cx, &s)));
permit2.release(&s);
assert_eq!(2, s.available_permits());
}
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