using System;

using System.Threading.Tasks;

using System.Collections.Generic;

public class Program

{

    public static async void Main()

    {

        Console.WriteLine("Hello World");

        TestTaskWhenAllException("only 1 that throws", Throws());

        TestTaskWhenAllException("only 1 that no throws", NoThrows());

        TestTaskWhenAllException("2 tasks, 1 that throws", Throws(), NoThrows());

        TestTaskWhenAllException("2 tasks, the other that throws", NoThrows(), Throws());

        TestTaskWhenAllException("2 tasks that throw", Throws(), Throws());

        TestTaskWhenAllException("2 tasks that no throw", NoThrows(), NoThrows());

    }

    private static async void TestTaskWhenAllException(string name, params Task[] tasks) {

        Console.WriteLine("Testing " + name);

        Task task = Task.WhenAll(tasks);

        try {

            await task;

        } catch (Exception e) {

            Console.WriteLine("\t - Thrown exception is "+e.GetType().ToString()+": "+e.Message);

            Console.WriteLine("\t - Task exception is "+task.Exception.GetType().ToString() + " (with " + task.Exception.InnerExceptions.Count + " inner): "+task.Exception.Message);

            Console.WriteLine("\t - Are they equal? "+(e == task.Exception).ToString());

        }

    }

    private static async Task Throws() {

        throw new ApplicationException("I miss the office grapes");

    }

    private static async Task NoThrows() {

        return;

    }

}