loom 0.3.1

Permutation testing for concurrent code
Documentation 
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#![deny(warnings, rust_2018_idioms)]

use loom::sync::atomic::AtomicUsize;
use loom::thread;

use std::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed, Release};
use std::sync::Arc;

#[test]
#[should_panic]
fn invalid_unsync_load_relaxed() {
    loom::model(|| {
        let a = Arc::new(AtomicUsize::new(0));
        let b = a.clone();

        let thread = thread::spawn(move || {
            unsafe { a.unsync_load() };
        });

        b.store(1, Relaxed);

        thread.join().unwrap();
    });
}

#[test]
#[ignore]
#[should_panic]
fn compare_and_swap_reads_old_values() {
    loom::model(|| {
        let a = Arc::new(AtomicUsize::new(0));
        let b = Arc::new(AtomicUsize::new(0));

        let a2 = a.clone();
        let b2 = b.clone();

        let th = thread::spawn(move || {
            a2.store(1, Release);
            b2.compare_and_swap(0, 2, AcqRel);
        });

        b.store(1, Release);
        a.compare_and_swap(0, 2, AcqRel);

        th.join().unwrap();

        let a_val = a.load(Acquire);
        let b_val = b.load(Acquire);

        if a_val == 2 && b_val == 2 {
            panic!();
        }
    });
}