Examples of *CancelledException causes.

ThreadCancelledExceptionTests.cs

using System;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Xunit;

namespace Junk.TaskCanceled.Tests
{
    [SuppressMessage("ReSharper", "MethodSupportsCancellation", Justification = "That's the point of the test.")]
    public class Tests
    {
        private const bool REQUEST_CANCELLATION = true;
        private const bool DO_NOT_REQUEST_CANCELLATION = true;

        [Theory(DisplayName = "Cases where ThreadCancelledException is thrown.")]
        [InlineData(REQUEST_CANCELLATION)]
        [InlineData(DO_NOT_REQUEST_CANCELLATION)]
        public void ThrowsTaskCancelledException(bool shouldRequestCancellation)
        {
            var cancellationTokenSource = new CancellationTokenSource();
            var cancellationToken = cancellationTokenSource.Token;

            var task = new Task(() => TaskCases.WaitUntil(100), cancellationToken);

            task.Start();
            if (shouldRequestCancellation)
                cancellationTokenSource.Cancel();

            var aggregateException = Assert.Throws<AggregateException>(() => task.Wait());
            Assert.Equal(1, aggregateException.InnerExceptions.Count);
            Assert.IsType<TaskCanceledException>(aggregateException.InnerExceptions[0]);
        }

        [Theory(DisplayName = "No exception is thrown at all.")]
        [InlineData(0)]
        [InlineData(100)]
        [InlineData(500)]
        public void NoExceptionThrown()
        {
            var cancellationTokenSource = new CancellationTokenSource();
            var cancellationToken = cancellationTokenSource.Token;

            var task = new Task(() => TaskCases.WaitUntil(100, cancellationToken));
            task.Start();
            cancellationTokenSource.Cancel();

            task.Wait(1);
        }

        [Theory(DisplayName = "Throws an OperationCancelledException")]
        public void ThrowsOperationCancelledException()
        {
            // TODO
        }
    }

    internal static class TaskCases
    {
        public static void WaitUntil(int milliseconds)
        {
            Thread.Sleep(milliseconds);
        }

        public static void WaitUntil(int milliseconds, CancellationToken token)
        {
            Thread.Sleep(milliseconds);
            if (token.IsCancellationRequested) return;
            throw new Exception("It wasn't cancelled!!!");
        }
    }
}