Github user NicoK commented on a diff in the pull request:
https://github.com/apache/flink/pull/4552#discussion_r161567305
--- Diff:
flink-runtime/src/test/java/org/apache/flink/runtime/io/network/netty/PartitionRequestQueueTest.java
---
@@ -71,4 +78,142 @@ public void testProducerFailedException() throws
Exception {
NettyMessage.ErrorResponse err = (NettyMessage.ErrorResponse)
msg;
assertTrue(err.cause instanceof CancelTaskException);
}
+
+ /**
+ * Tests {@link
PartitionRequestQueue#enqueueAvailableReader(SequenceNumberingViewReader)},
+ * verifying the reader would be enqueued in the pipeline if the next
sending buffer is event, even
+ * though it has no available credits.
+ */
+ @Test
+ public void testEnqueueReaderByNotifyingEventBuffer() throws Exception {
+ // setup
+ final ResultSubpartitionView view =
mock(ResultSubpartitionView.class);
+ when(view.nextBufferIsEvent()).thenReturn(true);
+
+ final ResultPartitionID partitionId = new ResultPartitionID();
+ final ResultPartitionProvider partitionProvider =
mock(ResultPartitionProvider.class);
+ when(partitionProvider.createSubpartitionView(
+ eq(partitionId),
+ eq(0),
+
any(BufferAvailabilityListener.class))).thenReturn(view);
+
+ final InputChannelID receiverId = new InputChannelID();
+ final PartitionRequestQueue queue = new PartitionRequestQueue();
+ final SequenceNumberingViewReader reader = new
SequenceNumberingViewReader(receiverId, 0, queue);
+ final EmbeddedChannel channel = new EmbeddedChannel(queue);
+
+ reader.requestSubpartitionView(partitionProvider, partitionId,
0);
+
+ // block the channel so that we see an intermediate state in
the test
+ ByteBuf channelBlockingBuffer = blockChannel(channel);
+ assertNull(channel.readOutbound());
+
+ // Notify an available event buffer to trigger enqueue the
reader
+ reader.notifyBuffersAvailable(1);
+
+ channel.runPendingTasks();
+
+ // The reader is enqueued in the pipeline because the next
buffer is an event, even though no credits are available
+ assertEquals(1, queue.getAvailableReaders().size());
+ assertEquals(0, reader.getNumCreditsAvailable());
+
+ // Flush the buffer to make the channel writable again and see
the final results
+ channel.flush();
+ assertSame(channelBlockingBuffer, channel.readOutbound());
+
+ assertEquals(0, queue.getAvailableReaders().size());
+ assertEquals(0, reader.getNumCreditsAvailable());
--- End diff --
let's end with `assertNull(channel.readOutbound());`
---
