public async Task PushAsync_WhileEnumerating_BackpressureIsHandled()
{
var stream = new MessageStreamEnumerable <int>();
using var enumerator = stream.GetEnumerator();
var pushTask1 = stream.PushAsync(new PushedMessage(1, 1));
var pushTask2 = stream.PushAsync(new PushedMessage(2, 2));
var pushTask3 = stream.PushAsync(new PushedMessage(3, 3));
enumerator.MoveNext();
await Task.Delay(100);
pushTask1.IsCompleted.Should().BeFalse();
enumerator.MoveNext();
await AsyncTestingUtil.WaitAsync(() => pushTask1.IsCompleted);
pushTask1.IsCompleted.Should().BeTrue();
await Task.Delay(100);
pushTask2.IsCompleted.Should().BeFalse();
pushTask3.IsCompleted.Should().BeFalse();
enumerator.MoveNext();
await AsyncTestingUtil.WaitAsync(() => pushTask2.IsCompleted);
pushTask2.IsCompleted.Should().BeTrue();
pushTask3.IsCompleted.Should().BeFalse();
}
public async Task PushAsyncGetEnumeratorAndCompleteAsync_SomeMessages_MessagesPushedAndReceived()
{
var stream = new MessageStreamEnumerable <int>();
var success = false;
var enumerationTask = Task.Run(
() =>
{
using var enumerator = stream.GetEnumerator();
enumerator.MoveNext().Should().BeTrue();
enumerator.Current.Should().Be(1);
enumerator.MoveNext().Should().BeTrue();
enumerator.Current.Should().Be(2);
enumerator.MoveNext().Should().BeTrue();
enumerator.Current.Should().Be(3);
enumerator.MoveNext().Should().BeFalse();
success = true;
});
await stream.PushAsync(new PushedMessage(1, 1));
await stream.PushAsync(new PushedMessage(2, 2));
await stream.PushAsync(new PushedMessage(3, 3));
await stream.CompleteAsync();
await enumerationTask;
success.Should().BeTrue();
}
public async Task Abort_WhileEnumerating_EnumerationAborted()
{
var completed = false;
var stream = new MessageStreamEnumerable <int>();
using var enumerator = stream.GetEnumerator();
// ReSharper disable once AccessToDisposedClosure
var enumerationTask = Task.Run(
() =>
{
enumerator.MoveNext();
completed = true;
});
completed.Should().BeFalse();
stream.Abort();
// Give the other thread a chance to exit the MoveNext
await AsyncTestingUtil.WaitAsync(() => enumerationTask.IsCompleted);
completed.Should().BeFalse();
enumerationTask.Status.Should().Be(TaskStatus.Faulted);
enumerationTask.Exception !.InnerExceptions.First().Should().BeAssignableTo <OperationCanceledException>();
}
public async Task CompleteAsync_WhileEnumerating_EnumerationCompleted()
{
var completed = false;
var stream = new MessageStreamEnumerable <int>();
using var enumerator = stream.GetEnumerator();
// The next MoveNext reaches the end of the enumerable
// ReSharper disable once AccessToDisposedClosure
Task.Run(
() =>
{
enumerator.MoveNext();
completed = true;
}).FireAndForget();
completed.Should().BeFalse();
await stream.CompleteAsync();
// Give the other thread a chance to exit the MoveNext
await AsyncTestingUtil.WaitAsync(() => completed);
completed.Should().BeTrue();
}