mono/mcs/class/corlib/Test/System.Threading.Tasks/TaskTest.cs

//
// TaskTest.cs
//
// Authors:
//	Marek Safar  <[email protected]>
//
// Copyright (c) 2008 Jérémie "Garuma" Laval
// Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
//

#if NET_4_0

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Collections.Generic;
using NUnit.Framework;

namespace MonoTests.System.Threading.Tasks
{
	[TestFixture]
	public class TaskTests
	{
		class MockScheduler : TaskScheduler
		{
			public event Action<Task, bool> TryExecuteTaskInlineHandler;

			protected override IEnumerable<Task> GetScheduledTasks ()
			{
				throw new NotImplementedException ();
			}

			protected override void QueueTask (Task task)
			{
				return;
			}

			protected override bool TryExecuteTaskInline (Task task, bool taskWasPreviouslyQueued)
			{
				if (TryExecuteTaskInlineHandler != null)
					TryExecuteTaskInlineHandler (task, taskWasPreviouslyQueued);

				return base.TryExecuteTask (task);
			}
		}


		Task[] tasks;
		const int max = 6;
		
		[SetUp]
		public void Setup()
		{
			tasks = new Task[max];			
		}
		
		void InitWithDelegate(Action action)
		{
			for (int i = 0; i < max; i++) {
				tasks[i] = Task.Factory.StartNew(action);
			}
		}
		
		[Test]
		public void WaitAnyTest()
		{
			ParallelTestHelper.Repeat (delegate {
				int flag = 0;
				int finished = 0;
				
				InitWithDelegate(delegate {
					int times = Interlocked.Exchange (ref flag, 1);
					if (times == 1) {
						SpinWait sw = new SpinWait ();
						while (finished == 0) sw.SpinOnce ();
					} else {
						Interlocked.Increment (ref finished);
					}
				});
				
				int index = Task.WaitAny(tasks, 1000);
				
				Assert.AreNotEqual (-1, index, "#3");
				Assert.AreEqual (1, flag, "#1");
				Assert.AreEqual (1, finished, "#2");
			});
		}

		[Test]
		public void WaitAny_Empty ()
		{
			Assert.AreEqual (-1, Task.WaitAny (new Task[0]));
		}

		[Test]
		public void WaitAny_Zero ()
		{
			Assert.AreEqual (-1, Task.WaitAny (new[] { new Task (delegate { })}, 0), "#1");
			Assert.AreEqual (-1, Task.WaitAny (new[] { new Task (delegate { }) }, 20), "#1");
		}

		[Test]
		public void WaitAny_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				new Task (delegate { }, cancelation.Token)
			};

			cancelation.Cancel ();

			Assert.AreEqual (1, Task.WaitAny (tasks, 1000), "#1");
			Assert.IsTrue (tasks[1].IsCompleted, "#2");
			Assert.IsTrue (tasks[1].IsCanceled, "#3");
		}

		[Test]
		public void WaitAny_CancelledWithoutExecution ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				new Task (delegate { })
			};

			int res = 0;
			var mre = new ManualResetEventSlim (false);
			ThreadPool.QueueUserWorkItem (delegate {
				res = Task.WaitAny (tasks, 20);
				mre.Set ();
			});

			cancelation.Cancel ();
			Assert.IsTrue (mre.Wait (1000), "#1");
			Assert.AreEqual (-1, res);
		}

		[Test]
		public void WaitAny_OneException ()
		{
			var mre = new ManualResetEventSlim (false);
			var tasks = new Task[] {
				Task.Factory.StartNew (delegate { mre.Wait (1000); }),
				Task.Factory.StartNew (delegate { throw new ApplicationException (); })
			};

			Assert.AreEqual (1, Task.WaitAny (tasks, 1000), "#1");
			Assert.IsFalse (tasks[0].IsCompleted, "#2");
			Assert.IsTrue (tasks[1].IsFaulted, "#3");

			mre.Set ();
		}

		[Test]
		public void WaitAny_SingleCanceled ()
		{
			var src = new CancellationTokenSource ();
			var t = Task.Factory.StartNew (() => { Thread.Sleep (200); src.Cancel (); src.Token.ThrowIfCancellationRequested (); }, src.Token);
			Assert.AreEqual (0, Task.WaitAny (new [] { t }));
		}

		public void WaitAny_ManyExceptions ()
		{
			CountdownEvent cde = new CountdownEvent (3);
			var tasks = new [] {
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } }),
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } }),
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } })
			};

			Assert.IsTrue (cde.Wait (1000), "#1");

			try {
				Assert.IsTrue (Task.WaitAll (tasks, 1000), "#2");
			} catch (AggregateException e) {
				Assert.AreEqual (3, e.InnerExceptions.Count, "#3");
			}
		}

		[Test]
		public void WaitAny_ManyCanceled ()
		{
			var cancellation = new CancellationToken (true);
			var tasks = new[] {
				Task.Factory.StartNew (delegate { }, cancellation),
				Task.Factory.StartNew (delegate { }, cancellation),
				Task.Factory.StartNew (delegate { }, cancellation)
			};

			try {
				Assert.IsTrue (Task.WaitAll (tasks, 1000), "#1");
			} catch (AggregateException e) {
				Assert.AreEqual (3, e.InnerExceptions.Count, "#2");
			}
		}
		
		[Test]
		public void WaitAllTest ()
		{
			ParallelTestHelper.Repeat (delegate {
				int achieved = 0;
				InitWithDelegate(delegate { Interlocked.Increment(ref achieved); });
				Task.WaitAll(tasks);
				Assert.AreEqual(max, achieved, "#1");
			});
		}

		[Test]
		public void WaitAll_ManyTasks ()
		{
			for (int r = 0; r < 2000; ++r) {
				var tasks = new Task[60];

				for (int i = 0; i < tasks.Length; i++) {
					tasks[i] = Task.Factory.StartNew (delegate { Thread.Sleep (0); });
				}

				Assert.IsTrue (Task.WaitAll (tasks, 2000));
			}
		}

		[Test]
		public void WaitAll_Zero ()
		{
			Assert.IsFalse (Task.WaitAll (new Task[1] { new Task (delegate { }) }, 0), "#0");
			Assert.IsFalse (Task.WaitAll (new Task[1] { new Task (delegate { }) }, 10), "#1");
		}

		[Test]
		public void WaitAll_WithExceptions ()
		{
			InitWithDelegate (delegate { throw new ApplicationException (); });

			try {
				Task.WaitAll (tasks);
				Assert.Fail ("#1");
			} catch (AggregateException e) {
				Assert.AreEqual (6, e.InnerExceptions.Count, "#2");
			}

			Assert.IsNotNull (tasks[0].Exception, "#3");
		}

		[Test]
		public void WaitAll_TimeoutWithExceptionsAfter ()
		{
			CountdownEvent cde = new CountdownEvent (2);
			var mre = new ManualResetEvent (false);
			var tasks = new[] {
				Task.Factory.StartNew (delegate { mre.WaitOne (); }),
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } }),
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } })
			};

			Assert.IsTrue (cde.Wait (1000), "#1");
			Assert.IsFalse (Task.WaitAll (tasks, 1000), "#2");

			mre.Set ();

			try {
				Assert.IsTrue (Task.WaitAll (tasks, 1000), "#3");
				Assert.Fail ("#4");
			} catch (AggregateException e) {
				Assert.AreEqual (2, e.InnerExceptions.Count, "#5");
			}
		}

		[Test]
		public void WaitAll_TimeoutWithExceptionsBefore ()
		{
			CountdownEvent cde = new CountdownEvent (2);
			var mre = new ManualResetEvent (false);
			var tasks = new[] {
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } }),
				Task.Factory.StartNew (delegate { try { throw new ApplicationException (); } finally { cde.Signal (); } }),
				Task.Factory.StartNew (delegate { mre.WaitOne (); })
			};

			Assert.IsTrue (cde.Wait (1000), "#1");
			Assert.IsFalse (Task.WaitAll (tasks, 1000), "#2");

			mre.Set ();

			try {
				Assert.IsTrue (Task.WaitAll (tasks, 1000), "#3");
				Assert.Fail ("#4");
			} catch (AggregateException e) {
				Assert.AreEqual (2, e.InnerExceptions.Count, "#5");
			}
		}

		[Test]
		public void WaitAll_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { cancelation.Cancel (); }),
				new Task (delegate { }, cancelation.Token)
			};

			tasks[0].Start ();

			try {
				Task.WaitAll (tasks);
				Assert.Fail ("#1");
			} catch (AggregateException e) {
				var inner = (TaskCanceledException) e.InnerException;
				Assert.AreEqual (tasks[1], inner.Task, "#2");
			}

			Assert.IsTrue (tasks[0].IsCompleted, "#3");
			Assert.IsTrue (tasks[1].IsCanceled, "#4");
		}

#if NET_4_5		
		[Test]
		public void WaitAll_CancelledAndTimeout ()
		{
			var ct = new CancellationToken (true);
			var t1 = new Task (() => {}, ct);
			var t2 = Task.Delay (3000);
			Assert.IsFalse (Task.WaitAll (new[] { t1, t2 }, 10));
		}
#endif

		[Test]
		public void WaitAllExceptionThenCancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { cancelation.Cancel (); throw new ApplicationException (); }),
				new Task (delegate { }, cancelation.Token)
			};

			tasks[0].Start ();

			try {
				Task.WaitAll (tasks);
				Assert.Fail ("#1");
			} catch (AggregateException e) {
				Assert.IsInstanceOfType (typeof (ApplicationException), e.InnerException, "#2");
				var inner = (TaskCanceledException) e.InnerExceptions[1];
				Assert.AreEqual (tasks[1], inner.Task, "#3");
			}

			Assert.IsTrue (tasks[0].IsCompleted, "#4");
			Assert.IsTrue (tasks[1].IsCanceled, "#5");
		}

		[Test]
		public void WaitAll_StartedUnderWait ()
		{
			var task1 = new Task (delegate { });

			ThreadPool.QueueUserWorkItem (delegate {
				// Sleep little to let task to start and hit internal wait
				Thread.Sleep (20);
				task1.Start ();
			});

			Assert.IsTrue (Task.WaitAll (new [] { task1 }, 1000), "#1");
		}

		[Test]
		public void CancelBeforeStart ()
		{
			var src = new CancellationTokenSource ();

			Task t = new Task (delegate { }, src.Token);
			src.Cancel ();
			Assert.AreEqual (TaskStatus.Canceled, t.Status, "#1");

			try {
				t.Start ();
				Assert.Fail ("#2");
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void Wait_CancelledTask ()
		{
			var src = new CancellationTokenSource ();

			Task t = new Task (delegate { }, src.Token);
			src.Cancel ();

			try {
				t.Wait (1000);
				Assert.Fail ("#1");
			} catch (AggregateException e) {
				var details = (TaskCanceledException) e.InnerException;
				Assert.AreEqual (t, details.Task, "#1e");
			}

			try {
				t.Wait ();
				Assert.Fail ("#2");
			} catch (AggregateException e) {
				var details = (TaskCanceledException) e.InnerException;
				Assert.AreEqual (t, details.Task, "#2e");
				Assert.IsNull (details.Task.Exception, "#2e2");
			}
		}

		[Test]
		public void Wait_Inlined ()
		{
			bool? previouslyQueued = null;

			var scheduler = new MockScheduler ();
			scheduler.TryExecuteTaskInlineHandler += (task, b) => {
				previouslyQueued = b;
			};

			var tf = new TaskFactory (scheduler);
			var t = tf.StartNew (() => { });
			t.Wait ();

			Assert.AreEqual (true, previouslyQueued);
		}

		[Test, ExpectedException (typeof (InvalidOperationException))]
		public void CreationWhileInitiallyCanceled ()
		{
			var token = new CancellationToken (true);
			var task = new Task (() => { }, token);
			Assert.AreEqual (TaskStatus.Canceled, task.Status);
			task.Start ();
		}

		[Test]
		public void ContinueWithInvalidArguments ()
		{
			var task = new Task (() => { });
			try {
				task.ContinueWith (null);
				Assert.Fail ("#1");
			} catch (ArgumentException) {
			}

			try {
				task.ContinueWith (delegate { }, null);
				Assert.Fail ("#2");
			} catch (ArgumentException) {
			}

			try {
				task.ContinueWith (delegate { }, TaskContinuationOptions.OnlyOnCanceled | TaskContinuationOptions.NotOnCanceled);
				Assert.Fail ("#3");
			} catch (ArgumentException) {
			}

			try {
				task.ContinueWith (delegate { }, TaskContinuationOptions.OnlyOnRanToCompletion | TaskContinuationOptions.NotOnRanToCompletion);
				Assert.Fail ("#4");
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void ContinueWithOnAnyTestCase()
		{
			ParallelTestHelper.Repeat (delegate {
				bool result = false;
				
				Task t = Task.Factory.StartNew(delegate { });
				Task cont = t.ContinueWith(delegate { result = true; }, TaskContinuationOptions.None);
				Assert.IsTrue (t.Wait (2000), "First wait, (status, {0})", t.Status);
				Assert.IsTrue (cont.Wait(2000), "Cont wait, (result, {0}) (parent status, {2}) (status, {1})", result, cont.Status, t.Status);
				Assert.IsNull(cont.Exception, "#1");
				Assert.IsNotNull(cont, "#2");
				Assert.IsTrue(result, "#3");
			});
		}
		
		[Test]
		public void ContinueWithOnCompletedSuccessfullyTestCase()
		{
			ParallelTestHelper.Repeat (delegate {
				bool result = false;
				
				Task t = Task.Factory.StartNew(delegate { });
				Task cont = t.ContinueWith(delegate { result = true; }, TaskContinuationOptions.OnlyOnRanToCompletion);
				Assert.IsTrue (t.Wait(1000), "#4");
				Assert.IsTrue (cont.Wait(1000), "#5");
				
				Assert.IsNull(cont.Exception, "#1");
				Assert.IsNotNull(cont, "#2");
				Assert.IsTrue(result, "#3");
			});
		}
		
		[Test]
		public void ContinueWithOnAbortedTestCase()
		{
			bool result = false;
			bool taskResult = false;

			CancellationTokenSource src = new CancellationTokenSource ();
			Task t = new Task (delegate { taskResult = true; }, src.Token);

			Task cont = t.ContinueWith (delegate { result = true; },
				TaskContinuationOptions.OnlyOnCanceled | TaskContinuationOptions.ExecuteSynchronously);

			src.Cancel ();

			Assert.AreEqual (TaskStatus.Canceled, t.Status, "#1a");
			Assert.IsTrue (cont.IsCompleted, "#1b");
			Assert.IsTrue (result, "#1c");

			try {
				t.Start ();
				Assert.Fail ("#2");
			} catch (InvalidOperationException) {
			}

			Assert.IsTrue (cont.Wait (1000), "#3");

			Assert.IsFalse (taskResult, "#4");

			Assert.IsNull (cont.Exception, "#5");
			Assert.AreEqual (TaskStatus.RanToCompletion, cont.Status, "#6");
		}
		
		[Test]
		public void ContinueWithOnFailedTestCase()
		{
			ParallelTestHelper.Repeat (delegate {
				bool result = false;
				
				Task t = Task.Factory.StartNew(delegate { throw new Exception("foo"); });	
				Task cont = t.ContinueWith(delegate { result = true; }, TaskContinuationOptions.OnlyOnFaulted);
			
				Assert.IsTrue (cont.Wait(1000), "#0");
				Assert.IsNotNull (t.Exception, "#1");
				Assert.IsNotNull (cont, "#2");
				Assert.IsTrue (result, "#3");
			});
		}

		[Test]
		public void ContinueWithWithStart ()
		{
			Task t = new Task<int> (() => 1);
			t = t.ContinueWith (l => { });
			try {
				t.Start ();
				Assert.Fail ();
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void ContinueWithChildren ()
		{
			ParallelTestHelper.Repeat (delegate {
			    bool result = false;

			    var t = Task.Factory.StartNew (() => Task.Factory.StartNew (() => {}, TaskCreationOptions.AttachedToParent));

				var mre = new ManualResetEvent (false);
			    t.ContinueWith (l => {
					result = true;
					mre.Set ();
				});

				Assert.IsTrue (mre.WaitOne (1000), "#1");
			    Assert.IsTrue (result, "#2");
			}, 2);
		}

		[Test]
		public void ContinueWithDifferentOptionsAreCanceledTest ()
		{
			var mre = new ManualResetEventSlim ();
			var task = Task.Factory.StartNew (() => mre.Wait (200));
			var contFailed = task.ContinueWith (t => {}, TaskContinuationOptions.OnlyOnFaulted);
			var contCanceled = task.ContinueWith (t => {}, TaskContinuationOptions.OnlyOnCanceled);
			var contSuccess = task.ContinueWith (t => {}, TaskContinuationOptions.OnlyOnRanToCompletion);

			mre.Set ();
			contSuccess.Wait (100);

			Assert.IsTrue (contSuccess.IsCompleted);
			Assert.IsTrue (contFailed.IsCompleted);
			Assert.IsTrue (contCanceled.IsCompleted);
			Assert.IsFalse (contSuccess.IsCanceled);
			Assert.IsTrue (contFailed.IsCanceled);
			Assert.IsTrue (contCanceled.IsCanceled);
		}

		[Test]
		public void MultipleTasks()
		{
			ParallelTestHelper.Repeat (delegate {
				bool r1 = false, r2 = false, r3 = false;
				
				Task t1 = Task.Factory.StartNew(delegate {
					r1 = true;
				});
				Task t2 = Task.Factory.StartNew(delegate {
					r2 = true;
				});
				Task t3 = Task.Factory.StartNew(delegate {
					r3 = true;
				});
				
				t1.Wait(2000);
				t2.Wait(2000);
				t3.Wait(2000);
				
				Assert.IsTrue(r1, "#1");
				Assert.IsTrue(r2, "#2");
				Assert.IsTrue(r3, "#3");
			}, 100);
		}
		
		[Test]
		public void WaitChildTestCase()
		{
			ParallelTestHelper.Repeat (delegate {
				bool r1 = false, r2 = false, r3 = false;
				var mre = new ManualResetEventSlim (false);
				var mreStart = new ManualResetEventSlim (false);
				
				Task t = Task.Factory.StartNew(delegate {
					Task.Factory.StartNew(delegate {
						mre.Wait (300);
						r1 = true;
					}, TaskCreationOptions.AttachedToParent);
					Task.Factory.StartNew(delegate {
						r2 = true;
					}, TaskCreationOptions.AttachedToParent);
					Task.Factory.StartNew(delegate {
						r3 = true;
					}, TaskCreationOptions.AttachedToParent);
					mreStart.Set ();
				});
				
				mreStart.Wait (300);
				Assert.IsFalse (t.Wait (10), "#0a");
				mre.Set ();
				Assert.IsTrue (t.Wait (500), "#0b");
				Assert.IsTrue(r2, "#1");
				Assert.IsTrue(r3, "#2");
				Assert.IsTrue(r1, "#3");
				Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#4");
			}, 10);
		}

		[Test]
		public void WaitChildWithContinuationAttachedTest ()
		{
			bool result = false;
			var task = new Task(() =>
			{
				Task.Factory.StartNew(() =>	{
					Thread.Sleep (200);
				}, TaskCreationOptions.AttachedToParent).ContinueWith(t => {
					Thread.Sleep (200);
					result = true;
				}, TaskContinuationOptions.AttachedToParent);
			});
			task.Start();
			task.Wait();
			Assert.IsTrue (result);
		}

		[Test]
		public void WaitChildWithContinuationNotAttachedTest ()
		{
			var task = new Task(() =>
			{
				Task.Factory.StartNew(() =>	{
					Thread.Sleep (200);
				}, TaskCreationOptions.AttachedToParent).ContinueWith(t => {
					Thread.Sleep (3000);
				});
			});
			task.Start();
			Assert.IsTrue (task.Wait(400));
		}

		[Test]
		public void WaitChildWithNesting ()
		{
			var result = false;
			var t = Task.Factory.StartNew (() => {
				Task.Factory.StartNew (() => {
					Task.Factory.StartNew (() => {
						Thread.Sleep (500);
						result = true;
					}, TaskCreationOptions.AttachedToParent);
				}, TaskCreationOptions.AttachedToParent);
			});
			t.Wait ();
			Assert.IsTrue (result);
		}

		[Test]
		public void DoubleWaitTest ()
		{
			ParallelTestHelper.Repeat (delegate {
				var evt = new ManualResetEventSlim ();
				var t = Task.Factory.StartNew (() => evt.Wait (5000));
				var cntd = new CountdownEvent (2);
				var cntd2 = new CountdownEvent (2);

				bool r1 = false, r2 = false;
				ThreadPool.QueueUserWorkItem (delegate { cntd.Signal (); r1 = t.Wait (1000) && t.Result; cntd2.Signal (); });
				ThreadPool.QueueUserWorkItem (delegate { cntd.Signal (); r2 = t.Wait (1000) && t.Result; cntd2.Signal (); });

				Assert.IsTrue (cntd.Wait (2000), "#1");
				evt.Set ();
				Assert.IsTrue (cntd2.Wait (2000), "#2");
				Assert.IsTrue (r1, "r1");
				Assert.IsTrue (r2, "r2");
			}, 10);
		}

		[Test]
		public void DoubleTimeoutedWaitTest ()
		{
			var evt = new ManualResetEventSlim ();
			var t = new Task (delegate { });
			var cntd = new CountdownEvent (2);

			bool r1 = false, r2 = false;
			ThreadPool.QueueUserWorkItem (delegate { r1 = !t.Wait (100); cntd.Signal (); });
			ThreadPool.QueueUserWorkItem (delegate { r2 = !t.Wait (100); cntd.Signal (); });

			cntd.Wait (2000);
			Assert.IsTrue (r1);
			Assert.IsTrue (r2);
		}

		[Test]
		public void RunSynchronously ()
		{
			var val = 0;
			Task t = new Task (() => { Thread.Sleep (100); val = 1; });
			t.RunSynchronously ();

			Assert.AreEqual (1, val, "#1");

			t = new Task (() => { Thread.Sleep (0); val = 2; });

			bool? previouslyQueued = null;

			var scheduler = new MockScheduler ();
			scheduler.TryExecuteTaskInlineHandler += (task, b) => {
				previouslyQueued = b;
			};

			t.RunSynchronously (scheduler);

			Assert.AreEqual (2, val, "#2");
			Assert.AreEqual (false, previouslyQueued, "#2a");
		}

		[Test]
		public void RunSynchronouslyArgumentChecks ()
		{
			Task t = new Task (() => { });
			try {
				t.RunSynchronously (null);
				Assert.Fail ("#1");
			} catch (ArgumentNullException) {
			}
		}

		[Test]
		public void RunSynchronouslyWithAttachedChildren ()
		{
			var result = false;
			var t = new Task (() => {
				Task.Factory.StartNew (() => { Thread.Sleep (500); result = true; }, TaskCreationOptions.AttachedToParent);
			});
			t.RunSynchronously ();
			Assert.IsTrue (result);
		}

		[Test]
		public void UnobservedExceptionOnFinalizerThreadTest ()
		{
			bool wasCalled = false;
			TaskScheduler.UnobservedTaskException += (o, args) => {
				wasCalled = true;
				args.SetObserved ();
			};
			var inner = new ApplicationException ();
			Task.Factory.StartNew (() => { throw inner; });
			Thread.Sleep (1000);
			GC.Collect ();
			Thread.Sleep (1000);
			GC.WaitForPendingFinalizers ();

			Assert.IsTrue (wasCalled);
		}

		[Test, ExpectedException (typeof (InvalidOperationException))]
		public void StartFinishedTaskTest ()
		{
			var t = Task.Factory.StartNew (delegate () { });
			t.Wait ();

			t.Start ();
		}

		[Test]
		public void Start_NullArgument ()
		{
			var t = Task.Factory.StartNew (delegate () { });
			try {
				t.Start (null);
				Assert.Fail ();
			} catch (ArgumentNullException) {
			}
		}

		[Test, ExpectedException (typeof (InvalidOperationException))]
		public void DisposeUnstartedTest ()
		{
			var t = new Task (() => { });
			t.Dispose ();
		}

		[Test]
		public void ThrowingUnrelatedCanceledExceptionTest ()
		{
			Task t = new Task (() => {
				throw new TaskCanceledException ();
			});

			t.RunSynchronously ();
			Assert.IsTrue (t.IsFaulted);
			Assert.IsFalse (t.IsCanceled);
		}

		[Test]
		public void CanceledContinuationExecuteSynchronouslyTest ()
		{
			var source = new CancellationTokenSource();
			var token = source.Token;
			var evt = new ManualResetEventSlim ();
			bool result = false;
			bool thrown = false;

			var task = Task.Factory.StartNew (() => evt.Wait (100));
			var cont = task.ContinueWith (t => result = true, token, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);

			source.Cancel();
			evt.Set ();
			task.Wait (100);
			try {
				cont.Wait (100);
			} catch (Exception ex) {
				thrown = true;
			}

			Assert.IsTrue (task.IsCompleted);
			Assert.IsTrue (cont.IsCanceled);
			Assert.IsFalse (result);
			Assert.IsTrue (thrown);
		}

		[Test]
		public void WhenChildTaskErrorIsThrownParentTaskShouldBeFaulted ()
		{
			Task innerTask = null;
			var testTask = new Task (() =>
			{
				innerTask = new Task (() => 
				{
					throw new InvalidOperationException ();
				}, TaskCreationOptions.AttachedToParent);
				innerTask.RunSynchronously ();
			});
			testTask.RunSynchronously ();

			Assert.AreNotEqual (TaskStatus.Running, testTask.Status);
			Assert.IsNotNull (innerTask);
			Assert.IsTrue (innerTask.IsFaulted);
			Assert.IsNotNull (testTask.Exception);
			Assert.IsTrue (testTask.IsFaulted);
			Assert.IsNotNull (innerTask.Exception);
		}
		
		[Test]
		public void WhenChildTaskErrorIsThrownOnlyOnFaultedContinuationShouldExecute ()
		{
			var continuationRan = false;
			var testTask = new Task (() =>
			{
				var task = new Task (() => 
				{
					throw new InvalidOperationException();
				}, TaskCreationOptions.AttachedToParent);
				task.RunSynchronously ();
			});
			var onErrorTask = testTask.ContinueWith (x => continuationRan = true, TaskContinuationOptions.OnlyOnFaulted);
			testTask.RunSynchronously ();
			onErrorTask.Wait (100);
			Assert.IsTrue (continuationRan);
		}
		
		[Test]
		public void WhenChildTaskErrorIsThrownNotOnFaultedContinuationShouldNotBeExecuted ()
		{
			var continuationRan = false;
			var testTask = new Task (() =>
			{
				var task = new Task (() => 
				{
					throw new InvalidOperationException();
				}, TaskCreationOptions.AttachedToParent);
				task.RunSynchronously();
			});
			var onErrorTask = testTask.ContinueWith (x => continuationRan = true, TaskContinuationOptions.NotOnFaulted);
			testTask.RunSynchronously ();
			Assert.IsTrue (onErrorTask.IsCompleted);
			Assert.IsFalse (onErrorTask.IsFaulted);
			Assert.IsFalse (continuationRan);
		}	
		
		[Test]
		public void WhenChildTaskSeveralLevelsDeepHandlesAggregateExceptionErrorStillBubblesToParent ()
		{
			var continuationRan = false;
			AggregateException e = null;
			var testTask = new Task (() =>
			{
				var child1 = new Task (() =>
				{
					var child2 = new Task (() => 
					{
						throw new InvalidOperationException();
					}, TaskCreationOptions.AttachedToParent);
					child2.RunSynchronously ();
				}, TaskCreationOptions.AttachedToParent);
				
				child1.RunSynchronously();
				e = child1.Exception;
				child1.Exception.Handle (ex => true);
			});
			var onErrorTask = testTask.ContinueWith (x => continuationRan = true, TaskContinuationOptions.OnlyOnFaulted);
			testTask.RunSynchronously ();
			onErrorTask.Wait (100);
			Assert.IsNotNull (e);
			Assert.IsTrue (continuationRan);
		}
		
		[Test]
		public void AlreadyCompletedChildTaskShouldRunContinuationImmediately ()
		{
			string result = "Failed";
			var testTask = new Task (() => 
			{
				var child = new Task<string> (() =>
				{
					return "Success";
				}, TaskCreationOptions.AttachedToParent);
				child.RunSynchronously ();
				child.ContinueWith (x => { Thread.Sleep (50); result = x.Result; }, TaskContinuationOptions.AttachedToParent | TaskContinuationOptions.NotOnFaulted);
			});
			testTask.RunSynchronously ();

			Assert.AreEqual ("Success", result);
		}

		[Test]
		public void InlineNotTrashingParentRelationship ()
		{
			bool r1 = false, r2 = false;
			var t = new Task (() => {
				new Task (() => { r1 = true; }, TaskCreationOptions.AttachedToParent).RunSynchronously ();
				Task.Factory.StartNew (() => { Thread.Sleep (100); r2 = true; }, TaskCreationOptions.AttachedToParent);
		    });
			t.RunSynchronously ();

			Assert.IsTrue (r1);
			Assert.IsTrue (r2);
		}

#if NET_4_5
		[Test]
		public void Delay_Invalid ()
		{
			try {
				Task.Delay (-100);
			} catch (ArgumentOutOfRangeException) {
			}
		}

		[Test]
		public void Delay_Start ()
		{
			var t = Task.Delay (5000);
			try {
				t.Start ();
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void Delay_Simple ()
		{
			var t = Task.Delay (300);
			Assert.IsTrue (TaskStatus.WaitingForActivation == t.Status || TaskStatus.Running == t.Status, "#1");
			Assert.IsTrue (t.Wait (400), "#2");
		}

		[Test]
		public void Delay_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();

			var t = Task.Delay (5000, cancelation.Token);
			Assert.IsTrue (TaskStatus.WaitingForActivation == t.Status || TaskStatus.Running == t.Status, "#1");
			cancelation.Cancel ();
			try {
				t.Wait (1000);
				Assert.Fail ("#2");
			} catch (AggregateException) {
				Assert.AreEqual (TaskStatus.Canceled, t.Status, "#3");
			}
			
			cancelation = new CancellationTokenSource ();
			t = Task.Delay (Timeout.Infinite, cancelation.Token);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#11");
			cancelation.Cancel ();
			try {
				t.Wait (1000);
				Assert.Fail ("#12");
			} catch (AggregateException) {
				Assert.AreEqual (TaskStatus.Canceled, t.Status, "#13");
			}
		}

		[Test]
		public void WaitAny_WithNull ()
		{
			var tasks = new [] {
				Task.FromResult (2),
				null
			};

			try {
				Task.WaitAny (tasks);
				Assert.Fail ();
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void WhenAll_WithNull ()
		{
			var tasks = new[] {
				Task.FromResult (2),
				null
			};

			try {
				Task.WhenAll (tasks);
				Assert.Fail ("#1");
			} catch (ArgumentException) {
			}

			tasks = null;
			try {
				Task.WhenAll (tasks);
				Assert.Fail ("#2");
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void WhenAll_Start ()
		{
			Task[] tasks = new[] {
				Task.FromResult (2),
			};

			var t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");

			try {
				t.Start ();
				Assert.Fail ("#2");
			} catch (InvalidOperationException) {
			}

			tasks = new [] {
				new Task (delegate { }),
			};

			t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#11");

			try {
				t.Start ();
				Assert.Fail ("#12");
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void WhenAll_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				new Task (delegate { }, cancelation.Token)
			};

			cancelation.Cancel ();

			var t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			tasks[0].Start ();

			try {
				Assert.IsTrue (t.Wait (1000), "#2");
				Assert.Fail ("#2a");
			} catch (AggregateException e) {
				Assert.IsInstanceOfType (typeof (TaskCanceledException), e.InnerException, "#3");
			}
		}

		[Test]
		public void WhenAll_Faulted ()
		{
			var tcs = new TaskCompletionSource<object> ();
			tcs.SetException (new ApplicationException ());

			var tcs2 = new TaskCompletionSource<object> ();
			tcs2.SetException (new InvalidTimeZoneException ());

			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				new Task (delegate { }, cancelation.Token),
				tcs.Task,
				tcs2.Task
			};

			cancelation.Cancel ();

			var t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			tasks[0].Start ();

			try {
				Assert.IsTrue (t.Wait (1000), "#2");
				Assert.Fail ("#2a");
			} catch (AggregateException e) {
				Assert.IsInstanceOfType (typeof (ApplicationException), e.InnerException, "#3");
				Assert.IsInstanceOfType (typeof (InvalidTimeZoneException), e.InnerExceptions[1], "#4");
			}
		}

		[Test]
		public void WhenAll ()
		{
			var t1 = new Task (delegate { });
			var t2 = new Task (delegate { t1.Start (); });

			var tasks = new Task[] {
				t1,
				t2,
			};

			var t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			t2.Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
		}

		[Test]
		public void WhenAllResult_WithNull ()
		{
			var tasks = new[] {
				Task.FromResult (2),
				null
			};

			try {
				Task.WhenAll<int> (tasks);
				Assert.Fail ("#1");
			} catch (ArgumentException) {
			}

			tasks = null;
			try {
				Task.WhenAll<int> (tasks);
				Assert.Fail ("#2");
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void WhenAllResult_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new [] {
				new Task<int> (delegate { return 9; }),
				new Task<int> (delegate { return 1; }, cancelation.Token)
			};

			cancelation.Cancel ();

			var t = Task.WhenAll (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			tasks[0].Start ();

			try {
				Assert.IsTrue (t.Wait (1000), "#2");
				Assert.Fail ("#2a");
			} catch (AggregateException e) {
				Assert.IsInstanceOfType (typeof (TaskCanceledException), e.InnerException, "#3");
			}

			try {
				var r = t.Result;
				Assert.Fail ("#4");
			} catch (AggregateException) {
			}
		}

		[Test]
		public void WhenAllResult ()
		{
			var t1 = new Task<string> (delegate { return "a"; });
			var t2 = new Task<string> (delegate { t1.Start (); return "b"; });

			var tasks = new [] {
				t1,
				t2,
			};

			var t = Task.WhenAll<string> (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			t2.Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.AreEqual (2, t.Result.Length, "#3");
			Assert.AreEqual ("a", t.Result[0], "#3a");
			Assert.AreEqual ("b", t.Result[1], "#3b");
		}

		[Test]
		public void WhenAllResult_Completed ()
		{
			var tasks = new[] {
				Task.FromResult (1),
				Task.FromResult (2)
			};

			var t = Task.WhenAll<int> (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");
			Assert.AreEqual (2, t.Result.Length, "#2");
			Assert.AreEqual (1, t.Result[0], "#2a");
			Assert.AreEqual (2, t.Result[1], "#2b");
		}

		[Test]
		public void WhenAny_WithNull ()
		{
			var tasks = new Task[] {
				Task.FromResult (2),
				null
			};

			try {
				Task.WhenAny (tasks);
				Assert.Fail ("#1");
			} catch (ArgumentException) {
			}

			tasks = null;
			try {
				Task.WhenAny (tasks);
				Assert.Fail ("#2");
			} catch (ArgumentException) {
			}

			try {
				Task.WhenAny (new Task[0]);
				Assert.Fail ("#3");
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void WhenAny_Start ()
		{
			Task[] tasks = new[] {
				Task.FromResult (2),
			};

			var t = Task.WhenAny (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");

			try {
				t.Start ();
				Assert.Fail ("#2");
			} catch (InvalidOperationException) {
			}

			tasks = new[] {
				new Task (delegate { }),
			};

			t = Task.WhenAny (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#11");

			try {
				t.Start ();
				Assert.Fail ("#12");
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void WhenAny_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				new Task (delegate { }, cancelation.Token)
			};

			cancelation.Cancel ();

			var t = Task.WhenAny (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");
			tasks[0].Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.AreEqual (TaskStatus.Canceled, t.Result.Status, "#3");
		}

		[Test]
		public void WhenAny_Faulted ()
		{
			var tcs = new TaskCompletionSource<object> ();
			tcs.SetException (new ApplicationException ());

			var tcs2 = new TaskCompletionSource<object> ();
			tcs2.SetException (new InvalidTimeZoneException ());

			var cancelation = new CancellationTokenSource ();
			var tasks = new Task[] {
				new Task (delegate { }),
				tcs.Task,
				new Task (delegate { }, cancelation.Token),
				tcs2.Task
			};

			cancelation.Cancel ();

			var t = Task.WhenAny (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");
			tasks[0].Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.IsNull (t.Exception, "#3");

			Assert.IsInstanceOfType (typeof (ApplicationException), t.Result.Exception.InnerException, "#4");
		}

		[Test]
		public void WhenAny ()
		{
			var t1 = new Task (delegate { });
			var t2 = new Task (delegate { t1.Start (); });

			var tasks = new Task[] {
				t1,
				t2,
			};

			var t = Task.WhenAny (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			t2.Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.IsNotNull (t.Result, "#3");
		}

		[Test]
		public void WhenAnyResult_WithNull ()
		{
			var tasks = new [] {
				Task.FromResult (2),
				null
			};

			try {
				Task.WhenAny<int> (tasks);
				Assert.Fail ("#1");
			} catch (ArgumentException) {
			}

			tasks = null;
			try {
				Task.WhenAny<int> (tasks);
				Assert.Fail ("#2");
			} catch (ArgumentException) {
			}

			try {
				Task.WhenAny<short> (new Task<short>[0]);
				Assert.Fail ("#3");
			} catch (ArgumentException) {
			}
		}

		[Test]
		public void WhenAnyResult_Start ()
		{
			var tasks = new[] {
				Task.FromResult (2),
			};

			var t = Task.WhenAny<int> (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");

			try {
				t.Start ();
				Assert.Fail ("#2");
			} catch (InvalidOperationException) {
			}

			tasks = new[] {
				new Task<int> (delegate { return 55; }),
			};

			t = Task.WhenAny<int> (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#11");

			try {
				t.Start ();
				Assert.Fail ("#12");
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void WhenAnyResult_Cancelled ()
		{
			var cancelation = new CancellationTokenSource ();
			var tasks = new [] {
				new Task<double> (delegate { return 1.1; }),
				new Task<double> (delegate { return -4.4; }, cancelation.Token)
			};

			cancelation.Cancel ();

			var t = Task.WhenAny<double> (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");
			tasks[0].Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.AreEqual (TaskStatus.Canceled, t.Result.Status, "#3");
		}

		[Test]
		public void WhenAnyResult_Faulted ()
		{
			var tcs = new TaskCompletionSource<object> ();
			tcs.SetException (new ApplicationException ());

			var tcs2 = new TaskCompletionSource<object> ();
			tcs2.SetException (new InvalidTimeZoneException ());

			var cancelation = new CancellationTokenSource ();
			var tasks = new Task<object>[] {
				new Task<object> (delegate { return null; }),
				tcs.Task,
				new Task<object> (delegate { return ""; }, cancelation.Token),
				tcs2.Task
			};

			cancelation.Cancel ();

			var t = Task.WhenAny<object> (tasks);
			Assert.AreEqual (TaskStatus.RanToCompletion, t.Status, "#1");
			tasks[0].Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.IsNull (t.Exception, "#3");

			Assert.IsInstanceOfType (typeof (ApplicationException), t.Result.Exception.InnerException, "#4");
		}

		[Test]
		public void WhenAnyResult ()
		{
			var t1 = new Task<byte> (delegate { return 3; });
			var t2 = new Task<byte> (delegate { t1.Start (); return 2; });

			var tasks = new [] {
				t1,
				t2,
			};

			var t = Task.WhenAny<byte> (tasks);
			Assert.AreEqual (TaskStatus.WaitingForActivation, t.Status, "#1");
			t2.Start ();

			Assert.IsTrue (t.Wait (1000), "#2");
			Assert.IsTrue (t.Result.Result > 1, "#3");
		}

		[Test]
		public void ContinueWith_StateValue ()
		{
			var t = Task.Factory.StartNew (l => {
				Assert.AreEqual (1, l, "a-1");
			}, 1);

			var c = t.ContinueWith ((a, b) => {
				Assert.AreEqual (t, a, "c-1");
				Assert.AreEqual (2, b, "c-2");
			}, 2);

			var d = t.ContinueWith ((a, b) => {
				Assert.AreEqual (t, a, "d-1");
				Assert.AreEqual (3, b, "d-2");
				return 77;
			}, 3);

			Assert.IsTrue (d.Wait (1000), "#1");

			Assert.AreEqual (1, t.AsyncState, "#2");
			Assert.AreEqual (2, c.AsyncState, "#3");
			Assert.AreEqual (3, d.AsyncState, "#4");
		}

		[Test]
		public void ContinueWith_StateValueGeneric ()
		{
			var t = Task<int>.Factory.StartNew (l => {
				Assert.AreEqual (1, l, "a-1");
				return 80;
			}, 1);

			var c = t.ContinueWith ((a, b) => {
				Assert.AreEqual (t, a, "c-1");
				Assert.AreEqual (2, b, "c-2");
				return "c";
			}, 2);

			var d = t.ContinueWith ((a, b) => {
				Assert.AreEqual (t, a, "d-1");
				Assert.AreEqual (3, b, "d-2");
				return 'd';
			}, 3);

			Assert.IsTrue (d.Wait (1000), "#1");

			Assert.AreEqual (1, t.AsyncState, "#2");
			Assert.AreEqual (80, t.Result, "#2r");
			Assert.AreEqual (2, c.AsyncState, "#3");
			Assert.AreEqual ("c", c.Result, "#3r");
			Assert.AreEqual (3, d.AsyncState, "#4");
			Assert.AreEqual ('d', d.Result, "#3r");
		}

		[Test]
		public void FromResult ()
		{
			var t = Task.FromResult<object> (null);
			Assert.IsTrue (t.IsCompleted, "#1");
			Assert.AreEqual (null, t.Result, "#2");
			t.Dispose ();
			t.Dispose ();
		}

		[Test]
		public void LongRunning ()
		{
			bool? is_tp = null;
			bool? is_bg = null;
			var t = new Task (() => { is_tp = Thread.CurrentThread.IsThreadPoolThread; is_bg = Thread.CurrentThread.IsBackground; });
			t.Start ();
			Assert.IsTrue (t.Wait (100));
			Assert.IsTrue ((bool)is_tp, "#1");
			Assert.IsTrue ((bool)is_bg, "#2");

			is_tp = null;
			is_bg = null;
			t = new Task (() => { is_tp = Thread.CurrentThread.IsThreadPoolThread; is_bg = Thread.CurrentThread.IsBackground; }, TaskCreationOptions.LongRunning);
			t.Start ();

			Assert.IsTrue (t.Wait (100));
			Assert.IsFalse ((bool) is_tp, "#11");
			Assert.IsTrue ((bool) is_bg, "#12");
		}

		[Test]
		public void Run_ArgumentCheck ()
		{
			try {
				Task.Run (null as Action);
				Assert.Fail ("#1");
			} catch (ArgumentNullException) {
			}
		}

		[Test]
		public void Run ()
		{
			bool ranOnDefaultScheduler = false;
			var t = Task.Run (delegate { ranOnDefaultScheduler = Thread.CurrentThread.IsThreadPoolThread; });
			Assert.AreEqual (TaskCreationOptions.DenyChildAttach, t.CreationOptions, "#1");
			t.Wait ();
			Assert.IsTrue (ranOnDefaultScheduler, "#2");
		}

		[Test]
		public void Run_Cancel ()
		{
			var t = Task.Run (() => 1, new CancellationToken (true));
			try {
				var r = t.Result;
				Assert.Fail ("#1");
			} catch (AggregateException) {
			}

			Assert.IsTrue (t.IsCanceled, "#2");
		}

		[Test]
		public void Run_ExistingTaskT ()
		{
			var t = new Task<int> (() => 5);
			var t2 = Task.Run (() => { t.Start (); return t; });

			Assert.IsTrue (t2.Wait (1000), "#1");
			Assert.AreEqual (5, t2.Result, "#2");
		}

		[Test]
		public void Run_ExistingTask ()
		{
			var t = new Task (delegate { throw new Exception ("Foo"); });
			var t2 = Task.Run (() => { t.Start (); return t; });

			try {
				t2.Wait (1000);
				Assert.Fail ();
			} catch (Exception) {}

			Assert.AreEqual (TaskStatus.Faulted, t.Status, "#2");
		}

		[Test]
		public void DenyChildAttachTest ()
		{
			var mre = new ManualResetEventSlim ();
			Task parent = Task.Factory.StartNew (() => {
				Task.Factory.StartNew (() => mre.Wait (2000), TaskCreationOptions.AttachedToParent);
			}, TaskCreationOptions.DenyChildAttach);
			Assert.IsTrue (parent.Wait (500), "#1");
			mre.Set ();
		}

		class SynchronousScheduler : TaskScheduler
		{
			protected override IEnumerable<Task> GetScheduledTasks ()
			{
				throw new NotImplementedException ();
			}

			protected override void QueueTask (Task task)
			{
				TryExecuteTaskInline (task, false);
			}

			protected override bool TryExecuteTaskInline (Task task, bool taskWasPreviouslyQueued)
			{
				return base.TryExecuteTask (task);
			}
		}

		[Test]
		public void HideSchedulerTest ()
		{
			var mre = new ManualResetEventSlim ();
			var ranOnDefault = false;
			var scheduler = new SynchronousScheduler ();

			Task parent = Task.Factory.StartNew (() => {
				Task.Factory.StartNew (() => {
					ranOnDefault = Thread.CurrentThread.IsThreadPoolThread;
					mre.Set ();
				});
			}, CancellationToken.None, TaskCreationOptions.HideScheduler, scheduler);

			Assert.IsTrue (mre.Wait (1000), "#1");
			Assert.IsTrue (ranOnDefault, "#2");
		}

		[Test]
		public void LazyCancelationTest ()
		{
			var source = new CancellationTokenSource ();
			source.Cancel ();
			var parent = new Task (delegate {});
			var cont = parent.ContinueWith (delegate {}, source.Token, TaskContinuationOptions.LazyCancellation, TaskScheduler.Default);

			Assert.AreNotEqual (TaskStatus.Canceled, cont.Status, "#1");
			parent.Start ();
			try {
				Assert.IsTrue (cont.Wait (1000), "#2");
				Assert.Fail ();
			} catch (AggregateException ex) {
				Assert.IsInstanceOfType (typeof (TaskCanceledException), ex.InnerException);
			}
		}
#endif
	}
}
#endif