rust/library/std/tests/thread.rs

use std::cell::{Cell, RefCell};
use std::sync::{Arc, Mutex};
use std::thread;
use std::time::Duration;

#[test]
#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
#[cfg_attr(miri, ignore)] // Miri does not like the thread leak
fn sleep_very_long() {
    let finished = Arc::new(Mutex::new(false));
    let t_finished = finished.clone();
    thread::spawn(move || {
        thread::sleep(Duration::new(u64::MAX, 0));
        *t_finished.lock().unwrap() = true;
    });
    thread::sleep(Duration::from_millis(100));
    assert_eq!(*finished.lock().unwrap(), false);
}

#[test]
fn thread_local_containing_const_statements() {
    // This exercises the `const $init:block` cases of the thread_local macro.
    // Despite overlapping with expression syntax, the `const { ... }` is not
    // parsed as `$init:expr`.
    thread_local! {
        static CELL: Cell<u32> = const {
            let value = 1;
            Cell::new(value)
        };

        static REFCELL: RefCell<u32> = const {
            let value = 1;
            RefCell::new(value)
        };
    }

    assert_eq!(CELL.get(), 1);
    assert_eq!(REFCELL.take(), 1);
}

#[test]
fn thread_local_hygeiene() {
    // Previously `thread_local_inner!` had use imports for `LocalKey`, `Storage`, `EagerStorage`
    // and `LazyStorage`. The use imports will shadow a user-provided type or type alias if the
    // user-provided type or type alias has the same name. Make sure that this does not happen. See
    // <https://github.com/rust-lang/rust/issues/131863>.
    //
    // NOTE: if the internal implementation details change (i.e. get renamed), this test should be
    // updated.

    #![allow(dead_code)]
    type LocalKey = ();
    type Storage = ();
    type LazyStorage = ();
    type EagerStorage = ();
    thread_local! {
        static A: LocalKey = const { () };
        static B: Storage = const { () };
        static C: LazyStorage = const { () };
        static D: EagerStorage = const { () };
    }
}

#[test]
// Include an ignore list on purpose, so that new platforms don't miss it
#[cfg_attr(
    any(
        target_os = "redox",
        target_os = "l4re",
        target_env = "sgx",
        target_os = "solid_asp3",
        target_os = "teeos",
        target_os = "wasi"
    ),
    should_panic
)]
fn available_parallelism() {
    // check that std::thread::available_parallelism() returns a valid value
    assert!(thread::available_parallelism().is_ok());
}