public async Task InitializeAsync()
{
GivenInternal();
SystemUnderTest = CreateSystemUnderTest();
await WhenInternalAsync().ConfigureAwait(false);
}
public async Task Subscriber_Not_Started_No_Buffer_Filled_Then_No_More_Messages_Requested()
{
// Arrange
int messagesFromQueue = 0;
int messagesDispatched = 0;
int receivebufferSize = 2;
int multiplexerCapacity = 2;
// plus one "in flight" between buffer and multiplexer
int expectedReceiveFromQueueCount = receivebufferSize + multiplexerCapacity + 1;
var sqsQueue = TestQueue(() => Interlocked.Increment(ref messagesFromQueue));
IMessageReceiveBuffer buffer = CreateMessageReceiveBuffer(sqsQueue, receivebufferSize);
IMessageDispatcher dispatcher =
new FakeDispatcher(() => Interlocked.Increment(ref messagesDispatched));
IMultiplexerSubscriber consumer1 = CreateSubscriber(dispatcher);
IMultiplexer multiplexer = CreateMultiplexer(multiplexerCapacity);
multiplexer.ReadFrom(buffer.Reader);
consumer1.Subscribe(multiplexer.GetMessagesAsync());
// need to start the multiplexer before calling Messages
using var cts = new CancellationTokenSource();
// Act and Assert
var multiplexerCompletion = multiplexer.RunAsync(cts.Token);
var bufferCompletion = buffer.RunAsync(cts.Token);
cts.CancelAfter(TimeSpan.FromSeconds(3));
await multiplexerCompletion.HandleCancellation();
await Assert.ThrowsAnyAsync <OperationCanceledException>(() => bufferCompletion);
await Patiently.AssertThatAsync(OutputHelper,
() =>
{
messagesFromQueue.ShouldBe(expectedReceiveFromQueueCount);
messagesDispatched.ShouldBe(0);
return(true);
});
// Starting the consumer after the token is cancelled will not dispatch messages
await Assert.ThrowsAnyAsync <OperationCanceledException>(() => consumer1.RunAsync(cts.Token));
await Patiently.AssertThatAsync(OutputHelper,
() =>
{
messagesFromQueue.ShouldBe(expectedReceiveFromQueueCount);
messagesDispatched.ShouldBe(0);
return(true);
});
}
public async Task WhenSubscriberNotStarted_BufferShouldFillUp_AndStopDownloading(int receivePrefetch, int receiveBufferSize, int multiplexerCapacity, int expectedDownloadCount)
{
var sqsQueue = TestQueue();
IMessageReceiveBuffer buffer = CreateMessageReceiveBuffer(sqsQueue, receivePrefetch, receiveBufferSize);
FakeDispatcher dispatcher = new FakeDispatcher();
IMultiplexerSubscriber consumer1 = CreateSubscriber(dispatcher);
IMultiplexer multiplexer = CreateMultiplexer(multiplexerCapacity);
multiplexer.ReadFrom(buffer.Reader);
consumer1.Subscribe(multiplexer.GetMessagesAsync());
OutputHelper.WriteLine("Multiplexer" + JsonConvert.SerializeObject(multiplexer.Interrogate()));
OutputHelper.WriteLine("MessageReceiveBuffer" + JsonConvert.SerializeObject(buffer.Interrogate()));
using var cts = new CancellationTokenSource();
// Act and Assert
var multiplexerCompletion = multiplexer.RunAsync(cts.Token);
var bufferCompletion = buffer.RunAsync(cts.Token);
cts.CancelAfter(3.Seconds());
await multiplexerCompletion.HandleCancellation();
await bufferCompletion.HandleCancellation();
sqsQueue.ReceiveMessageRequests.Sum(x => x.NumMessagesReceived).ShouldBe(expectedDownloadCount);
dispatcher.DispatchedMessages.Count.ShouldBe(0);
// Starting the consumer after the token is cancelled will not dispatch messages
await Assert.ThrowsAnyAsync <OperationCanceledException>(() => consumer1.RunAsync(cts.Token));
await Patiently.AssertThatAsync(OutputHelper,
() =>
{
sqsQueue.ReceiveMessageRequests.Sum(x => x.NumMessagesReceived).ShouldBe(expectedDownloadCount);
dispatcher.DispatchedMessages.Count.ShouldBe(0);
});
}
