fn test_multiple_threads_with_threadpool()

in utils/src/singleflight.rs [423:454]

• 31 lines of code
• 2 McCabe index (conditional complexity)

    fn test_multiple_threads_with_threadpool() {
        let times_called = Arc::new(AtomicU32::new(0));
        let threadpool = Arc::new(ThreadPool::new().unwrap());
        let g: Arc<Group<usize, ()>> = Arc::new(Group::new());
        let mut handlers: Vec<JoinHandle<(usize, bool)>> = Vec::new();
        let threadpool_ = threadpool.clone();
        let tasks = async move {
            for _ in 0..10 {
                let g = g.clone();
                let counter = times_called.clone();
                handlers.push(threadpool_.spawn(async move {
                    let tup = g.work("key", expensive_fn(counter, RES)).await;
                    let res = tup.0;
                    let fn_response = res.unwrap();
                    (fn_response, tup.1)
                }));
            }

            let num_callers = join_all(handlers)
                .await
                .into_iter()
                .map(|r| r.unwrap())
                .filter(|(val, is_caller)| {
                    assert_eq!(*val, RES);
                    *is_caller
                })
                .count();
            assert_eq!(1, num_callers);
            assert_eq!(1, times_called.load(Ordering::SeqCst));
        };
        let _ = threadpool.external_run_async_task(tasks).unwrap();
    }