Run_When_Called_From_Multiple_Threads_Then_All_Tasks_Executed.cs

    [TestMethod]
    public async Task Run_When_Called_From_Multiple_Threads_Then_All_Tasks_Executed()
    {
      const int NUMBER_OF_SCHEDULED_TASKS = 100;
      const int DEFAULT_TASK_SLEEP = 100;
      const int NUMBER_OF_WORKER_THREAD = 3;
      var countDownEvent = new CountdownEvent(NUMBER_OF_WORKER_THREAD);

      int executedTasks = 0;

      var allTasks = Enumerable.Range(0, NUMBER_OF_SCHEDULED_TASKS).Select(_ => m_scheduler.Post(() => Thread.Sleep(DEFAULT_TASK_SLEEP))).ToArray();

      Enumerable.Range(0, NUMBER_OF_WORKER_THREAD).Select(_ => ThreadPool.QueueUserWorkItem(__ =>
      {
        int tasksExecutedInThisThread = m_scheduler.Run();
        Interlocked.Add(ref executedTasks, tasksExecutedInThisThread);
        countDownEvent.Signal();
      })).ToArray();

      await Task.WhenAll(allTasks);
      countDownEvent.Wait();

      Assert.AreEqual(NUMBER_OF_SCHEDULED_TASKS, executedTasks);
    }