Function check_wait_blocks

tests/BS_thread_pool_test.cpp:1450–1486

* @brief Check that wait() correctly blocks all external threads that call it. */

 * @brief Check that wait() correctly blocks all external threads that call it.
 */
void check_wait_blocks()
{
    constexpr std::chrono::milliseconds sleep_time(100);
    constexpr std::size_t num_waiting_tasks = 4;
    BS::thread_pool pool;
    binary_semaphore sem(0);
    logln("Checking that wait() correctly blocks all external threads that call it...");
    pool.detach_task(
        [&sem]
        {
            logln("Task submitted to pool 1 and waiting to be released...");
            sem.acquire();
            logln("Task released.");
        });
    BS::thread_pool temp_pool(num_waiting_tasks);
    std::vector<std::atomic<bool>> flags(num_waiting_tasks);
    const auto waiting_task = [&flags, &pool](const std::size_t task_num)
    {
        logln("Task ", task_num, " submitted to pool 2 and waiting for pool 1's task to finish...");
        pool.wait();
        logln("Task ", task_num, " finished waiting.");
        flags[task_num] = true;
    };
    for (std::size_t i = 0; i < num_waiting_tasks; ++i)
    {
        temp_pool.detach_task(
            [&waiting_task, i]
            {
                waiting_task(i);
            });
    }
    std::this_thread::sleep_for(sleep_time);
    check(no_flags_set(flags));
    sem.release();
    temp_pool.wait();
    check(all_flags_set(flags));
}

/**
 * @brief Check that wait_for() works.