/
AwaitExtensionsTests.cs
887 lines (797 loc) · 31.5 KB
/
AwaitExtensionsTests.cs
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// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.VisualStudio.Threading;
using Microsoft.Win32;
using Xunit;
using Xunit.Abstractions;
#pragma warning disable CA1416 // Validate platform compatibility
public partial class AwaitExtensionsTests : TestBase
{
public AwaitExtensionsTests(ITestOutputHelper logger)
: base(logger)
{
}
public enum NamedSyncContext
{
None,
A,
B,
}
[Theory, CombinatorialData]
public void TaskYield_ConfigureAwait_OnDispatcher(bool useDefaultYield)
{
this.ExecuteOnDispatcher(async delegate
{
var asyncLocal = new System.Threading.AsyncLocal<object> { Value = 3 };
int originalThreadId = Environment.CurrentManagedThreadId;
if (useDefaultYield)
{
await Task.Yield();
}
else
{
await Task.Yield().ConfigureAwait(true);
}
Assert.Equal(3, asyncLocal.Value);
Assert.Equal(originalThreadId, Environment.CurrentManagedThreadId);
await Task.Yield().ConfigureAwait(false);
Assert.Equal(3, asyncLocal.Value);
Assert.NotEqual(originalThreadId, Environment.CurrentManagedThreadId);
});
}
[Theory, CombinatorialData]
public void TaskYield_ConfigureAwait_OnDefaultSyncContext(bool useDefaultYield)
{
Task.Run(async delegate
{
SynchronizationContext defaultSyncContext = new SynchronizationContext();
SynchronizationContext.SetSynchronizationContext(defaultSyncContext);
var asyncLocal = new System.Threading.AsyncLocal<object> { Value = 3 };
if (useDefaultYield)
{
await Task.Yield();
}
else
{
await Task.Yield().ConfigureAwait(true);
}
Assert.Equal(3, asyncLocal.Value);
Assert.Null(SynchronizationContext.Current);
await Task.Yield().ConfigureAwait(false);
Assert.Equal(3, asyncLocal.Value);
Assert.Null(SynchronizationContext.Current);
});
}
[Theory, CombinatorialData]
public void TaskYield_ConfigureAwait_OnNonDefaultTaskScheduler(bool useDefaultYield)
{
var scheduler = new MockTaskScheduler();
Task.Factory.StartNew(
async delegate
{
var asyncLocal = new System.Threading.AsyncLocal<object> { Value = 3 };
if (useDefaultYield)
{
await Task.Yield();
}
else
{
await Task.Yield().ConfigureAwait(true);
}
Assert.Equal(3, asyncLocal.Value);
Assert.Same(scheduler, TaskScheduler.Current);
await Task.Yield().ConfigureAwait(false);
Assert.Equal(3, asyncLocal.Value);
Assert.NotSame(scheduler, TaskScheduler.Current);
},
CancellationToken.None,
TaskCreationOptions.None,
scheduler).Unwrap().GetAwaiter().GetResult();
}
[Theory, CombinatorialData]
public void TaskYield_ConfigureAwait_OnDefaultTaskScheduler(bool useDefaultYield)
{
Task.Run(
async delegate
{
var asyncLocal = new System.Threading.AsyncLocal<object> { Value = 3 };
if (useDefaultYield)
{
await Task.Yield();
}
else
{
await Task.Yield().ConfigureAwait(true);
}
Assert.Equal(3, asyncLocal.Value);
Assert.Same(TaskScheduler.Default, TaskScheduler.Current);
await Task.Yield().ConfigureAwait(false);
Assert.Equal(3, asyncLocal.Value);
Assert.Same(TaskScheduler.Default, TaskScheduler.Current);
}).GetAwaiter().GetResult();
}
[Theory, CombinatorialData]
public async Task TaskYield_ConfigureAwait_OnCompleted_CapturesExecutionContext(bool captureContext)
{
var taskResultSource = new TaskCompletionSource<object?>();
System.Threading.AsyncLocal<object?> asyncLocal = new System.Threading.AsyncLocal<object?>();
asyncLocal.Value = "expected";
Task.Yield().ConfigureAwait(captureContext).GetAwaiter().OnCompleted(delegate
{
try
{
Assert.Equal("expected", asyncLocal.Value);
taskResultSource.SetResult(null);
}
catch (Exception ex)
{
taskResultSource.SetException(ex);
}
});
asyncLocal.Value = null;
await taskResultSource.Task;
}
[Fact]
public void AwaitCustomTaskScheduler()
{
var mockScheduler = new MockTaskScheduler();
Task.Run(async delegate
{
await mockScheduler;
Assert.Equal(1, mockScheduler.QueueTaskInvocations);
Assert.Same(mockScheduler, TaskScheduler.Current);
}).GetAwaiter().GetResult();
}
[Fact]
public void AwaitCustomTaskSchedulerNoYieldWhenAlreadyOnScheduler()
{
var mockScheduler = new MockTaskScheduler();
Task.Run(async delegate
{
await mockScheduler;
Assert.True(mockScheduler.GetAwaiter().IsCompleted, "We're already executing on that scheduler, so no reason to yield.");
}).GetAwaiter().GetResult();
}
[Fact]
public void AwaitThreadPoolSchedulerYieldsOnNonThreadPoolThreads()
{
// In some test runs (including VSTS cloud test), this test runs on a threadpool thread.
if (Thread.CurrentThread.IsThreadPoolThread)
{
Task? testResult = Task.Factory.StartNew(
delegate
{
Assert.False(Thread.CurrentThread.IsThreadPoolThread); // avoid infinite recursion if it doesn't get us off a threadpool thread.
this.AwaitThreadPoolSchedulerYieldsOnNonThreadPoolThreads();
},
CancellationToken.None,
TaskCreationOptions.LongRunning, // arrange for a dedicated thread
TaskScheduler.Default);
testResult.GetAwaiter().GetResult(); // rethrow any test failure.
return; // skip the test that runs on this thread.
}
Assert.False(TaskScheduler.Default.GetAwaiter().IsCompleted);
}
[Fact]
public void AwaitThreadPoolSchedulerNoYieldOnThreadPool()
{
Task.Run(delegate
{
Assert.True(Thread.CurrentThread.IsThreadPoolThread, "Test depends on thread looking like threadpool thread.");
Assert.True(TaskScheduler.Default.GetAwaiter().IsCompleted);
}).GetAwaiter().GetResult();
}
[Theory]
[CombinatorialData]
public void ConfigureAwaitRunInline_NoExtraThreadSwitching(NamedSyncContext invokeOn, NamedSyncContext completeOn)
{
// Set up various SynchronizationContexts that we may invoke or complete the async method with.
SynchronizationContext? aSyncContext = SingleThreadedTestSynchronizationContext.New();
SynchronizationContext? bSyncContext = SingleThreadedTestSynchronizationContext.New();
SynchronizationContext? invokeOnSyncContext = invokeOn == NamedSyncContext.None ? null
: invokeOn == NamedSyncContext.A ? aSyncContext
: invokeOn == NamedSyncContext.B ? bSyncContext
: throw new ArgumentOutOfRangeException(nameof(invokeOn));
SynchronizationContext? completeOnSyncContext = completeOn == NamedSyncContext.None ? null
: completeOn == NamedSyncContext.A ? aSyncContext
: completeOn == NamedSyncContext.B ? bSyncContext
: throw new ArgumentOutOfRangeException(nameof(completeOn));
// Set up a single-threaded SynchronizationContext that we'll invoke the async method within.
SynchronizationContext.SetSynchronizationContext(invokeOnSyncContext);
var unblockAsyncMethod = new TaskCompletionSource<bool>();
Task<int>? asyncTask = AwaitThenGetThreadAsync(unblockAsyncMethod.Task);
SynchronizationContext.SetSynchronizationContext(completeOnSyncContext);
unblockAsyncMethod.SetResult(true);
// Confirm that setting the intermediate task allowed the async method to complete immediately, using our thread to do it.
Assert.True(asyncTask.IsCompleted);
Assert.Equal(Environment.CurrentManagedThreadId, asyncTask.Result);
async Task<int> AwaitThenGetThreadAsync(Task antecedent)
{
await antecedent.ConfigureAwaitRunInline();
return Environment.CurrentManagedThreadId;
}
}
[Theory]
[CombinatorialData]
public void ConfigureAwaitRunInlineOfT_NoExtraThreadSwitching(NamedSyncContext invokeOn, NamedSyncContext completeOn)
{
// Set up various SynchronizationContexts that we may invoke or complete the async method with.
SynchronizationContext? aSyncContext = SingleThreadedTestSynchronizationContext.New();
SynchronizationContext? bSyncContext = SingleThreadedTestSynchronizationContext.New();
SynchronizationContext? invokeOnSyncContext = invokeOn == NamedSyncContext.None ? null
: invokeOn == NamedSyncContext.A ? aSyncContext
: invokeOn == NamedSyncContext.B ? bSyncContext
: throw new ArgumentOutOfRangeException(nameof(invokeOn));
SynchronizationContext? completeOnSyncContext = completeOn == NamedSyncContext.None ? null
: completeOn == NamedSyncContext.A ? aSyncContext
: completeOn == NamedSyncContext.B ? bSyncContext
: throw new ArgumentOutOfRangeException(nameof(completeOn));
// Set up a single-threaded SynchronizationContext that we'll invoke the async method within.
SynchronizationContext.SetSynchronizationContext(invokeOnSyncContext);
var unblockAsyncMethod = new TaskCompletionSource<bool>();
Task<int>? asyncTask = AwaitThenGetThreadAsync(unblockAsyncMethod.Task);
SynchronizationContext.SetSynchronizationContext(completeOnSyncContext);
unblockAsyncMethod.SetResult(true);
// Confirm that setting the intermediate task allowed the async method to complete immediately, using our thread to do it.
Assert.True(asyncTask.IsCompleted);
Assert.Equal(Environment.CurrentManagedThreadId, asyncTask.Result);
async Task<int> AwaitThenGetThreadAsync(Task<bool> antecedent)
{
bool result = await antecedent.ConfigureAwaitRunInline();
Assert.True(result);
return Environment.CurrentManagedThreadId;
}
}
[Fact]
public void ConfigureAwaitRunInline_AlreadyCompleted()
{
Task<int>? asyncTask = AwaitThenGetThreadAsync(Task.FromResult(true));
Assert.True(asyncTask.IsCompleted);
Assert.Equal(Environment.CurrentManagedThreadId, asyncTask.Result);
async Task<int> AwaitThenGetThreadAsync(Task antecedent)
{
await antecedent.ConfigureAwaitRunInline();
return Environment.CurrentManagedThreadId;
}
}
[Fact]
public void ConfigureAwaitRunInlineOfT_AlreadyCompleted()
{
Task<int>? asyncTask = AwaitThenGetThreadAsync(Task.FromResult(true));
Assert.True(asyncTask.IsCompleted);
Assert.Equal(Environment.CurrentManagedThreadId, asyncTask.Result);
async Task<int> AwaitThenGetThreadAsync(Task<bool> antecedent)
{
bool result = await antecedent.ConfigureAwaitRunInline();
Assert.True(result);
return Environment.CurrentManagedThreadId;
}
}
[Fact]
public async Task AwaitTaskScheduler_UnsafeOnCompleted_DoesNotCaptureExecutionContext()
{
var taskResultSource = new TaskCompletionSource<object?>();
System.Threading.AsyncLocal<object?> asyncLocal = new System.Threading.AsyncLocal<object?>();
asyncLocal.Value = "expected";
TaskScheduler.Default.GetAwaiter().UnsafeOnCompleted(delegate
{
try
{
Assert.Null(asyncLocal.Value);
taskResultSource.SetResult(null);
}
catch (Exception ex)
{
taskResultSource.SetException(ex);
}
});
asyncLocal.Value = null;
await taskResultSource.Task;
}
[Theory, CombinatorialData]
public async Task AwaitTaskScheduler_OnCompleted_CapturesExecutionContext(bool defaultTaskScheduler)
{
var taskResultSource = new TaskCompletionSource<object?>();
System.Threading.AsyncLocal<object?> asyncLocal = new System.Threading.AsyncLocal<object?>();
asyncLocal.Value = "expected";
TaskScheduler scheduler = defaultTaskScheduler ? TaskScheduler.Default : new MockTaskScheduler();
scheduler.GetAwaiter().OnCompleted(delegate
{
try
{
Assert.Equal("expected", asyncLocal.Value);
taskResultSource.SetResult(null);
}
catch (Exception ex)
{
taskResultSource.SetException(ex);
}
});
asyncLocal.Value = null;
await taskResultSource.Task;
}
[Fact]
public void AwaitWaitHandle()
{
var handle = new ManualResetEvent(initialState: false);
Func<Task> awaitHelper = async delegate
{
await handle;
};
Task awaitHelperResult = awaitHelper();
Assert.False(awaitHelperResult.IsCompleted);
handle.Set();
awaitHelperResult.Wait();
}
[Fact]
public async Task WaitForExit_NullArgument()
{
await Assert.ThrowsAsync<ArgumentNullException>(() => AwaitExtensions.WaitForExitAsync(null!));
}
[SkippableFact]
public async Task WaitForExitAsync_ExitCode()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
Process p = Process.Start(
new ProcessStartInfo("cmd.exe", "/c exit /b 55")
{
CreateNoWindow = true,
WindowStyle = ProcessWindowStyle.Hidden,
})!;
int exitCode = await AwaitExtensions.WaitForExitAsync(p);
Assert.Equal(55, exitCode);
}
[SkippableFact]
public void WaitForExitAsync_AlreadyExited()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
Process p = Process.Start(
new ProcessStartInfo("cmd.exe", "/c exit /b 55")
{
CreateNoWindow = true,
WindowStyle = ProcessWindowStyle.Hidden,
})!;
p.WaitForExit();
Task<int> t = AwaitExtensions.WaitForExitAsync(p);
Assert.True(t.IsCompleted);
Assert.Equal(55, t.Result);
}
[Fact]
public async Task WaitForExitAsync_UnstartedProcess()
{
string processName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "cmd.exe" : "/bin/bash";
var process = new Process();
process.StartInfo.FileName = processName;
process.StartInfo.CreateNoWindow = true;
await Assert.ThrowsAsync<InvalidOperationException>(() => process.WaitForExitAsync());
}
[Fact]
public async Task WaitForExitAsync_DoesNotCompleteTillKilled()
{
string processName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "cmd.exe" : "/bin/bash";
int expectedExitCode = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? -1 : 128 + 9; // https://stackoverflow.com/a/1041309
Process p = Process.Start(new ProcessStartInfo(processName) { CreateNoWindow = true, WindowStyle = ProcessWindowStyle.Hidden })!;
try
{
Task<int> t = AwaitExtensions.WaitForExitAsync(p);
Assert.False(t.IsCompleted);
p.Kill();
int exitCode = await t;
Assert.Equal(expectedExitCode, exitCode);
}
catch
{
try
{
p.Kill();
}
catch
{
}
throw;
}
}
[Fact]
public async Task WaitForExitAsync_Canceled()
{
string processName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "cmd.exe" : "/bin/bash";
Process p = Process.Start(new ProcessStartInfo(processName) { CreateNoWindow = true, WindowStyle = ProcessWindowStyle.Hidden })!;
try
{
var cts = new CancellationTokenSource();
Task<int> t = AwaitExtensions.WaitForExitAsync(p, cts.Token);
Assert.False(t.IsCompleted);
cts.Cancel();
await Assert.ThrowsAsync<TaskCanceledException>(() => t);
}
finally
{
p.Kill();
}
}
[Fact]
public async Task ConfigureAwaitForAggregateException_WithoutThrowing()
{
Task task = Task.FromResult(0);
await task.ConfigureAwaitForAggregateException();
}
[Theory]
[CombinatorialData]
public void ConfigureAwaitForAggregateException_OnDispatcher(bool continueOnCapturedContext)
{
this.ExecuteOnDispatcher(async delegate
{
int dispatcherThread = Environment.CurrentManagedThreadId;
var tcs = new TaskCompletionSource<object?>();
async Task Helper()
{
await tcs.Task.ConfigureAwaitForAggregateException(continueOnCapturedContext);
Assert.Equal(continueOnCapturedContext, dispatcherThread == Environment.CurrentManagedThreadId);
}
Task helperTask = Helper();
tcs.SetResult(null);
await helperTask;
});
}
[Fact]
public async Task ConfigureAwaitForAggregateException_ThrowsAggregateException()
{
Task fail1 = Task.FromException(new InvalidOperationException());
Task fail2 = Task.FromException(new ApplicationException());
Task joint = Task.WhenAll(fail1, fail2);
try
{
await joint.ConfigureAwaitForAggregateException();
Assert.False(true, "Exception was not thrown.");
}
catch (AggregateException ex)
{
Assert.Contains(fail1.Exception!.InnerException, ex.InnerExceptions);
Assert.Contains(fail2.Exception!.InnerException, ex.InnerExceptions);
}
}
[Fact]
public async Task ConfigureAwaitForAggregateException_Canceled()
{
Task canceled = Task.FromCanceled(new CancellationToken(true));
try
{
await canceled.ConfigureAwaitForAggregateException();
Assert.False(true, "Exception was not thrown.");
}
catch (OperationCanceledException)
{
}
}
[Fact]
public async Task ConfigureAwaitForAggregateException_InnerCanceled()
{
Task canceled1 = Task.FromCanceled(new CancellationToken(true));
Task canceled2 = Task.FromCanceled(new CancellationToken(true));
Task result = Task.FromResult<object?>(null);
Task joint = Task.WhenAll(canceled1, canceled2, result);
try
{
await joint.ConfigureAwaitForAggregateException();
Assert.False(true, "Exception was not thrown.");
}
catch (OperationCanceledException)
{
}
}
[Fact]
public async Task ConfigureAwaitForAggregateException_InnerCanceledAndFaulted()
{
Task canceled = Task.FromCanceled(new CancellationToken(true));
Task faulted = Task.FromException(new InvalidOperationException());
Task result = Task.FromResult<object?>(null);
Task joint = Task.WhenAll(canceled, faulted, result);
try
{
await joint.ConfigureAwaitForAggregateException();
Assert.False(true, "Exception was not thrown.");
}
catch (AggregateException ex)
{
Assert.Contains(faulted.Exception!.InnerException, ex.InnerExceptions);
Assert.Single(ex.InnerExceptions);
}
}
[Fact]
public void GetAwaiter_SynchronizationContext_ValidatesArgs()
{
Assert.Throws<ArgumentNullException>(() => AwaitExtensions.GetAwaiter((SynchronizationContext)null!));
}
[Fact]
public async Task SyncContext_Awaiter()
{
TaskCompletionSource<SingleThreadedSynchronizationContext> syncContextSource = new();
SingleThreadedSynchronizationContext.Frame frame = new();
Thread? otherThread = null;
Task otherThreadTask = Task.Run(delegate
{
SingleThreadedSynchronizationContext syncContext;
try
{
syncContext = new();
otherThread = Thread.CurrentThread;
syncContextSource.SetResult(syncContext);
}
catch (Exception ex)
{
syncContextSource.SetException(ex);
throw;
}
syncContext.PushFrame(frame);
});
try
{
SynchronizationContext context = await syncContextSource.Task;
Assert.NotSame(Thread.CurrentThread, otherThread);
await context;
Assert.Same(Thread.CurrentThread, otherThread);
await Task.Yield();
Assert.Same(Thread.CurrentThread, otherThread);
await TaskScheduler.Default.SwitchTo(alwaysYield: true);
Assert.NotSame(Thread.CurrentThread, otherThread);
}
finally
{
frame.Continue = false;
}
}
[SkippableFact]
public async Task AwaitRegKeyChange()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
Task changeWatcherTask = test.Key.WaitForChangeAsync();
Assert.False(changeWatcherTask.IsCompleted);
test.Key.SetValue("a", "b");
await changeWatcherTask;
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_TwoAtOnce_SameKeyHandle()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
Task changeWatcherTask1 = test.Key.WaitForChangeAsync();
Task changeWatcherTask2 = test.Key.WaitForChangeAsync();
Assert.False(changeWatcherTask1.IsCompleted);
Assert.False(changeWatcherTask2.IsCompleted);
test.Key.SetValue("a", "b");
await Task.WhenAll(changeWatcherTask1, changeWatcherTask2);
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_NoChange()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
Task changeWatcherTask = test.Key.WaitForChangeAsync(cancellationToken: test.FinishedToken);
Assert.False(changeWatcherTask.IsCompleted);
// Give a bit of time to confirm the task will not complete.
Task completedTask = await Task.WhenAny(changeWatcherTask, Task.Delay(AsyncDelay));
Assert.NotSame(changeWatcherTask, completedTask);
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_WatchSubtree()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
using (RegistryKey? subKey = test.CreateSubKey())
{
Task changeWatcherTask = test.Key.WaitForChangeAsync(watchSubtree: true, cancellationToken: test.FinishedToken);
subKey.SetValue("subkeyValueName", "b");
await changeWatcherTask;
}
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_KeyDeleted()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
using (RegistryKey? subKey = test.CreateSubKey())
{
Task changeWatcherTask = subKey.WaitForChangeAsync(watchSubtree: true, cancellationToken: test.FinishedToken);
test.Key.DeleteSubKey(Path.GetFileName(subKey.Name));
await changeWatcherTask;
}
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_NoWatchSubtree()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
using (RegistryKey? subKey = test.CreateSubKey())
{
Task changeWatcherTask = test.Key.WaitForChangeAsync(watchSubtree: false, cancellationToken: test.FinishedToken);
subKey.SetValue("subkeyValueName", "b");
// We do not expect changes to sub-keys to complete the task, so give a bit of time to confirm
// the task doesn't complete.
Task completedTask = await Task.WhenAny(changeWatcherTask, Task.Delay(AsyncDelay));
Assert.NotSame(changeWatcherTask, completedTask);
}
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_Canceled()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
var cts = new CancellationTokenSource();
Task changeWatcherTask = test.Key.WaitForChangeAsync(cancellationToken: cts.Token);
Assert.False(changeWatcherTask.IsCompleted);
cts.Cancel();
try
{
await changeWatcherTask;
Assert.True(false, "Expected exception not thrown.");
}
catch (OperationCanceledException ex)
{
Assert.Equal(cts.Token, ex.CancellationToken);
}
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_KeyDisposedWhileWatching()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
Task watchingTask;
using (var test = new RegKeyTest())
{
watchingTask = test.Key.WaitForChangeAsync();
}
// We expect the task to quietly complete (without throwing any exception).
await watchingTask;
}
[SkippableFact]
public async Task AwaitRegKeyChange_CanceledAndImmediatelyDisposed()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
Task watchingTask;
CancellationToken expectedCancellationToken;
using (var test = new RegKeyTest())
{
expectedCancellationToken = test.FinishedToken;
watchingTask = test.Key.WaitForChangeAsync(cancellationToken: test.FinishedToken);
}
try
{
await watchingTask;
Assert.True(false, "Expected exception not thrown.");
}
catch (OperationCanceledException ex)
{
Assert.Equal(expectedCancellationToken, ex.CancellationToken);
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_CallingThreadDestroyed()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
using (var test = new RegKeyTest())
{
// Start watching and be certain the thread that started watching is destroyed.
// This simulates a more common case of someone on a threadpool thread watching
// a key asynchronously and then the .NET Threadpool deciding to reduce the number of threads in the pool.
Task? watchingTask = null;
var thread = new Thread(() =>
{
watchingTask = test.Key.WaitForChangeAsync(cancellationToken: test.FinishedToken);
});
thread.Start();
thread.Join();
// Verify that the watching task is still watching.
Task completedTask = await Task.WhenAny(watchingTask!, Task.Delay(AsyncDelay));
Assert.NotSame(watchingTask, completedTask);
test.CreateSubKey().Dispose();
await watchingTask!;
}
}
[SkippableFact]
public async Task AwaitRegKeyChange_DoesNotPreventAppTerminationOnWin7()
{
Skip.IfNot(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
string testExePath = Path.Combine(
AppDomain.CurrentDomain.BaseDirectory!,
"..",
"..",
"..",
"Microsoft.VisualStudio.Threading.Tests.Win7RegistryWatcher",
#if DEBUG
"Debug",
#else
"Release",
#endif
"net472",
"Microsoft.VisualStudio.Threading.Tests.Win7RegistryWatcher.exe");
this.Logger.WriteLine("Using testexe path: {0}", testExePath);
var psi = new ProcessStartInfo(testExePath)
{
CreateNoWindow = true,
WindowStyle = ProcessWindowStyle.Hidden,
};
Process testExeProcess = Process.Start(psi)!;
try
{
// The assertion and timeout are interesting here:
// If the dedicated thread is not a background thread, the process does
// seem to terminate anyway, but it can sometimes (3 out of 10 times)
// take up to 10 seconds to terminate (perhaps when a GC finalizer runs?)
// while other times it's really fast.
// But when the dedicated thread is a background thread, it seems reliably fast.
this.TimeoutTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(8));
int exitCode = await AwaitExtensions.WaitForExitAsync(testExeProcess, this.TimeoutToken);
Assert.Equal(0, exitCode);
}
finally
{
if (!testExeProcess.HasExited)
{
testExeProcess.Kill();
}
}
}
private class RegKeyTest : IDisposable
{
private readonly string keyName;
private readonly RegistryKey key;
private readonly CancellationTokenSource testFinished = new CancellationTokenSource();
internal RegKeyTest()
{
this.keyName = "test_" + Path.GetRandomFileName();
this.key = Registry.CurrentUser.CreateSubKey(this.keyName, RegistryKeyPermissionCheck.ReadWriteSubTree, RegistryOptions.Volatile);
}
public RegistryKey Key => this.key;
public CancellationToken FinishedToken => this.testFinished.Token;
public RegistryKey CreateSubKey(string? name = null)
{
return this.key.CreateSubKey(name ?? Path.GetRandomFileName(), RegistryKeyPermissionCheck.Default, RegistryOptions.Volatile);
}
public void Dispose()
{
this.testFinished.Cancel();
this.testFinished.Dispose();
this.key.Dispose();
Registry.CurrentUser.DeleteSubKeyTree(this.keyName);
}
}
private class MockTaskScheduler : TaskScheduler
{
internal int QueueTaskInvocations { get; set; }
protected override IEnumerable<Task> GetScheduledTasks()
{
return Enumerable.Empty<Task>();
}
protected override void QueueTask(Task task)
{
this.QueueTaskInvocations++;
ThreadPool.QueueUserWorkItem(state => this.TryExecuteTask((Task)state!), task);
}
protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
{
return false;
}
}
}