public async Task Await_TaskCompletesOnNonDefaultSyncCtx_ContinuesOnDefaultSyncCtx()
{
await Task.Run(async delegate // escape xunit's sync context
{
Assert.Null(SynchronizationContext.Current);
Assert.Same(TaskScheduler.Default, TaskScheduler.Current);
var ctx = new ValidateCorrectContextSynchronizationContext();
var tcs = new TaskCompletionSource <bool>();
var ignored = Task.Delay(1).ContinueWith(_ =>
{
SynchronizationContext orig = SynchronizationContext.Current;
SynchronizationContext.SetSynchronizationContext(ctx);
try
{
tcs.SetResult(true);
}
finally
{
SynchronizationContext.SetSynchronizationContext(orig);
}
}, TaskScheduler.Default);
await tcs.Task;
Assert.Null(SynchronizationContext.Current);
Assert.Same(TaskScheduler.Default, TaskScheduler.Current);
});
}
public static async Task AsyncMethod_Yields_ReturnsToCorrectSynchronizationContext()
{
var sc = new ValidateCorrectContextSynchronizationContext ();
SynchronizationContext.SetSynchronizationContext(sc);
await Task.Yield();
Assert.Equal(1, sc.PostCount);
}
public static void OnCompleted_CompletesInAnotherSynchronizationContext(bool generic, bool? continueOnCapturedContext)
{
SynchronizationContext origCtx = SynchronizationContext.Current;
try
{
// Create a context that tracks operations, and set it as current
var validateCtx = new ValidateCorrectContextSynchronizationContext();
Assert.Equal(0, validateCtx.PostCount);
SynchronizationContext.SetSynchronizationContext(validateCtx);
// Create a not-completed task and get an awaiter for it
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
// Hook up a callback
bool postedInContext = false;
Action callback = () =>
{
postedInContext = ValidateCorrectContextSynchronizationContext.IsPostedInContext;
mres.Set();
};
if (generic)
{
if (continueOnCapturedContext.HasValue) tcs.Task.ConfigureAwait(continueOnCapturedContext.Value).GetAwaiter().OnCompleted(callback);
else tcs.Task.GetAwaiter().OnCompleted(callback);
}
else
{
if (continueOnCapturedContext.HasValue) ((Task)tcs.Task).ConfigureAwait(continueOnCapturedContext.Value).GetAwaiter().OnCompleted(callback);
else ((Task)tcs.Task).GetAwaiter().OnCompleted(callback);
}
Assert.False(mres.IsSet, "Callback should not yet have run.");
// Complete the task in another context and wait for the callback to run
Task.Run(() => tcs.SetResult(null));
mres.Wait();
// Validate the callback ran and in the correct context
bool shouldHavePosted = !continueOnCapturedContext.HasValue || continueOnCapturedContext.Value;
Assert.Equal(shouldHavePosted ? 1 : 0, validateCtx.PostCount);
Assert.Equal(shouldHavePosted, postedInContext);
}
finally
{
// Reset back to the original context
SynchronizationContext.SetSynchronizationContext(origCtx);
}
}
public static void OnCompleted_CompletesInAnotherSynchronizationContext(bool generic, bool?continueOnCapturedContext)
{
SynchronizationContext origCtx = SynchronizationContext.Current;
try
{
// Create a context that tracks operations, and set it as current
var validateCtx = new ValidateCorrectContextSynchronizationContext();
Assert.Equal(0, validateCtx.PostCount);
SynchronizationContext.SetSynchronizationContext(validateCtx);
// Create a not-completed task and get an awaiter for it
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
// Hook up a callback
bool postedInContext = false;
Action callback = () =>
{
postedInContext = ValidateCorrectContextSynchronizationContext.t_isPostedInContext;
mres.Set();
};
if (generic)
{
if (continueOnCapturedContext.HasValue)
{
tcs.Task.ConfigureAwait(continueOnCapturedContext.Value).GetAwaiter().OnCompleted(callback);
}
else
{
tcs.Task.GetAwaiter().OnCompleted(callback);
}
}
else
{
if (continueOnCapturedContext.HasValue)
{
((Task)tcs.Task).ConfigureAwait(continueOnCapturedContext.Value).GetAwaiter().OnCompleted(callback);
}
else
{
((Task)tcs.Task).GetAwaiter().OnCompleted(callback);
}
}
Assert.False(mres.IsSet, "Callback should not yet have run.");
// Complete the task in another context and wait for the callback to run
Task.Run(() => tcs.SetResult(null));
mres.Wait();
// Validate the callback ran and in the correct context
bool shouldHavePosted = !continueOnCapturedContext.HasValue || continueOnCapturedContext.Value;
Assert.Equal(shouldHavePosted ? 1 : 0, validateCtx.PostCount);
Assert.Equal(shouldHavePosted, postedInContext);
}
finally
{
// Reset back to the original context
SynchronizationContext.SetSynchronizationContext(origCtx);
}
}
public static void RunAsyncTaskAwaiterTests()
{
var completed = new TaskCompletionSource<string>();
Task task = completed.Task;
Task<string> taskOfString = completed.Task;
completed.SetResult("42");
{
// IsCompleted/OnCompleted on a non-completed Task with SyncContext and completes the task in another context
var vccsc = new ValidateCorrectContextSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(vccsc);
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
int result = 1;
var awaiter = ((Task)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext, " > FAILURE. Continuation should be running in captured sync context.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not run until task completes.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should have completed.");
Assert.True(vccsc.PostCount == 1, " > FAILURE. Await continuation should have posted to the target context.");
SynchronizationContext.SetSynchronizationContext(null);
}
{
// IsCompleted/OnCompleted on a non-completed Task with TaskScheduler and completes the task in another context
var quwi = new QUWITaskScheduler();
RunWithSchedulerAsCurrent(quwi, delegate
{
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
int result = 1;
var awaiter = ((Task)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(TaskScheduler.Current == quwi, " > FAILURE. Continuation should be running in task scheduler.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not run until task completes.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should have completed.");
});
}
{
// Configured IsCompleted/OnCompleted on a non-completed Task with SyncContext
for (int iter = 0; iter < 2; iter++)
{
Task.Factory.StartNew(() =>
{
bool continueOnCapturedContext = iter == 0;
SynchronizationContext.SetSynchronizationContext(new ValidateCorrectContextSynchronizationContext());
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
int result = 1;
var awaiter = ((Task)tcs.Task).ConfigureAwait(continueOnCapturedContext).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Configured awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext == continueOnCapturedContext,
" > FAILURE. Continuation should have been posted to context iff continueOnCapturedContext == true.");
//
// Assert.True(Environment.StackTrace.Contains("SetResult") != continueOnCapturedContext,
// " > FAILURE. Continuation should have been executed synchronously iff continueOnCapturedContext == false.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Factory.StartNew(() => tcs.SetResult(null));
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
SynchronizationContext.SetSynchronizationContext(null);
}, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Wait();
}
}
{
// IsCompleted/OnCompleted on a non-completed Task<TResult> with SyncContext and completes the task in another context
var vccsc = new ValidateCorrectContextSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(vccsc);
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
int result = 1;
var awaiter = ((Task<object>)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed Task<TResult> should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext, " > FAILURE. Await continuation should have posted to target context");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
Assert.True(vccsc.PostCount == 1, " > FAILURE. Await continuation should have posted to the target context");
SynchronizationContext.SetSynchronizationContext(null);
}
{
// Configured IsCompleted/OnCompleted on a non-completed Task<TResult> with SyncContext
for (int iter = 0; iter < 2; iter++)
{
Task.Factory.StartNew(() =>
{
bool continueOnCapturedContext = iter == 0;
SynchronizationContext.SetSynchronizationContext(new ValidateCorrectContextSynchronizationContext());
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource<object>();
int result = 1;
var awaiter = tcs.Task.ConfigureAwait(continueOnCapturedContext).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Configured awaiter on non-completed Task<TResult> should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(
ValidateCorrectContextSynchronizationContext.IsPostedInContext == continueOnCapturedContext,
" > FAILURE. Await continuation should have posted to target context iff continueOnCapturedContext == true");
// Assert.True(
// Environment.StackTrace.Contains("SetResult") != continueOnCapturedContext,
// " > FAILURE. Await continuation should have executed inline iff continueOnCapturedContext == false");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Factory.StartNew(() => tcs.SetResult(null));
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
SynchronizationContext.SetSynchronizationContext(null);
}, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Wait();
}
}
{
// Validate successful GetResult
task.GetAwaiter().GetResult();
task.ConfigureAwait(false).GetAwaiter().GetResult();
task.ConfigureAwait(true).GetAwaiter().GetResult();
Assert.Equal(taskOfString.GetAwaiter().GetResult(), "42");
Assert.Equal(taskOfString.ConfigureAwait(false).GetAwaiter().GetResult(), "42");
Assert.Equal(taskOfString.ConfigureAwait(true).GetAwaiter().GetResult(), "42");
}
{
// Validate GetResult blocks until completion
var tcs = new TaskCompletionSource<bool>();
// Kick off tasks that should all block
var t1 = Task.Factory.StartNew(() => tcs.Task.GetAwaiter().GetResult());
var t2 = Task.Factory.StartNew(() => ((Task)tcs.Task).GetAwaiter().GetResult());
var t3 = Task.Factory.StartNew(() => tcs.Task.ConfigureAwait(false).GetAwaiter().GetResult());
var t4 = Task.Factory.StartNew(() => ((Task)tcs.Task).ConfigureAwait(false).GetAwaiter().GetResult());
var allTasks = new Task[] { t1, t2, t3, t4 };
// Wait with timeout should return false
bool waitCompleted;
try
{
waitCompleted = Task.WaitAll(allTasks, 4000);
Assert.False(waitCompleted, " > Expected tasks to not be completed");
}
catch (Exception exc)
{
Assert.True(false, string.Format(" > Did not expect an exception: " + exc));
}
// Now complete the tasks
tcs.SetResult(true);
// All tasks should complete successfully
waitCompleted = Task.WaitAll(allTasks, 4000);
Assert.True(waitCompleted,
"After completion, excepted all GetResult calls to completed successfully");
foreach (var taskToCheck in allTasks)
{
Assert.True(taskToCheck.Status == TaskStatus.RanToCompletion, "Task was not run to completion. Excepted all GetResult calls to completed successfully");
}
}
}
public static void RunAsyncTaskAwaiterTests()
{
var completed = new TaskCompletionSource <string>();
Task task = completed.Task;
Task <string> taskOfString = completed.Task;
completed.SetResult("42");
{
// IsCompleted/OnCompleted on a non-completed Task with SyncContext and completes the task in another context
var vccsc = new ValidateCorrectContextSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(vccsc);
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
int result = 1;
var awaiter = ((Task)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext, " > FAILURE. Continuation should be running in captured sync context.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not run until task completes.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should have completed.");
Assert.True(vccsc.PostCount == 1, " > FAILURE. Await continuation should have posted to the target context.");
SynchronizationContext.SetSynchronizationContext(null);
}
{
// IsCompleted/OnCompleted on a non-completed Task with TaskScheduler and completes the task in another context
var quwi = new QUWITaskScheduler();
RunWithSchedulerAsCurrent(quwi, delegate
{
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
int result = 1;
var awaiter = ((Task)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(TaskScheduler.Current == quwi, " > FAILURE. Continuation should be running in task scheduler.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not run until task completes.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should have completed.");
});
}
{
// Configured IsCompleted/OnCompleted on a non-completed Task with SyncContext
for (int iter = 0; iter < 2; iter++)
{
Task.Factory.StartNew(() =>
{
bool continueOnCapturedContext = iter == 0;
SynchronizationContext.SetSynchronizationContext(new ValidateCorrectContextSynchronizationContext());
ManualResetEventSlim mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
int result = 1;
var awaiter = ((Task)tcs.Task).ConfigureAwait(continueOnCapturedContext).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Configured awaiter on non-completed task should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext == continueOnCapturedContext,
" > FAILURE. Continuation should have been posted to context iff continueOnCapturedContext == true.");
//
// Assert.True(Environment.StackTrace.Contains("SetResult") != continueOnCapturedContext,
// " > FAILURE. Continuation should have been executed synchronously iff continueOnCapturedContext == false.");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Factory.StartNew(() => tcs.SetResult(null));
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
SynchronizationContext.SetSynchronizationContext(null);
}, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Wait();
}
}
{
// IsCompleted/OnCompleted on a non-completed Task<TResult> with SyncContext and completes the task in another context
var vccsc = new ValidateCorrectContextSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(vccsc);
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
int result = 1;
var awaiter = ((Task <object>)tcs.Task).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Awaiter on non-completed Task<TResult> should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(ValidateCorrectContextSynchronizationContext.IsPostedInContext, " > FAILURE. Await continuation should have posted to target context");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Run(delegate { tcs.SetResult(null); });
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
Assert.True(vccsc.PostCount == 1, " > FAILURE. Await continuation should have posted to the target context");
SynchronizationContext.SetSynchronizationContext(null);
}
{
// Configured IsCompleted/OnCompleted on a non-completed Task<TResult> with SyncContext
for (int iter = 0; iter < 2; iter++)
{
Task.Factory.StartNew(() =>
{
bool continueOnCapturedContext = iter == 0;
SynchronizationContext.SetSynchronizationContext(new ValidateCorrectContextSynchronizationContext());
var mres = new ManualResetEventSlim();
var tcs = new TaskCompletionSource <object>();
int result = 1;
var awaiter = tcs.Task.ConfigureAwait(continueOnCapturedContext).GetAwaiter();
Assert.False(awaiter.IsCompleted, " > FAILURE. Configured awaiter on non-completed Task<TResult> should not be IsCompleted");
awaiter.OnCompleted(() =>
{
Assert.True(
ValidateCorrectContextSynchronizationContext.IsPostedInContext == continueOnCapturedContext,
" > FAILURE. Await continuation should have posted to target context iff continueOnCapturedContext == true");
// Assert.True(
// Environment.StackTrace.Contains("SetResult") != continueOnCapturedContext,
// " > FAILURE. Await continuation should have executed inline iff continueOnCapturedContext == false");
result = 2;
mres.Set();
});
Assert.True(result == 1, " > FAILURE. Await continuation should not have run before task completed.");
Task.Factory.StartNew(() => tcs.SetResult(null));
mres.Wait();
awaiter.GetResult();
Assert.True(result == 2, " > FAILURE. Await continuation should now have completed.");
SynchronizationContext.SetSynchronizationContext(null);
}, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Wait();
}
}
{
// Validate successful GetResult
task.GetAwaiter().GetResult();
task.ConfigureAwait(false).GetAwaiter().GetResult();
task.ConfigureAwait(true).GetAwaiter().GetResult();
Assert.Equal(taskOfString.GetAwaiter().GetResult(), "42");
Assert.Equal(taskOfString.ConfigureAwait(false).GetAwaiter().GetResult(), "42");
Assert.Equal(taskOfString.ConfigureAwait(true).GetAwaiter().GetResult(), "42");
}
{
// Validate GetResult blocks until completion
var tcs = new TaskCompletionSource <bool>();
// Kick off tasks that should all block
var t1 = Task.Factory.StartNew(() => tcs.Task.GetAwaiter().GetResult());
var t2 = Task.Factory.StartNew(() => ((Task)tcs.Task).GetAwaiter().GetResult());
var t3 = Task.Factory.StartNew(() => tcs.Task.ConfigureAwait(false).GetAwaiter().GetResult());
var t4 = Task.Factory.StartNew(() => ((Task)tcs.Task).ConfigureAwait(false).GetAwaiter().GetResult());
var allTasks = new Task[] { t1, t2, t3, t4 };
// Wait with timeout should return false
bool waitCompleted;
try
{
waitCompleted = Task.WaitAll(allTasks, 4000);
Assert.False(waitCompleted, " > Expected tasks to not be completed");
}
catch (Exception exc)
{
Assert.True(false, string.Format(" > Did not expect an exception: " + exc));
}
// Now complete the tasks
tcs.SetResult(true);
// All tasks should complete successfully
waitCompleted = Task.WaitAll(allTasks, 4000);
Assert.True(waitCompleted,
"After completion, excepted all GetResult calls to completed successfully");
foreach (var taskToCheck in allTasks)
{
Assert.True(taskToCheck.Status == TaskStatus.RanToCompletion, "Task was not run to completion. Excepted all GetResult calls to completed successfully");
}
}
}
