FlowControlHandlerTest invalid condition

Motivation:
FlowControlHandlerTest attempts to validate the expected contents of the underlying queue in FlowControlHandler. However the condition which triggers the check is too early and the queue contents may not yet contain all expected objects. For example a CountDownLatch is counted down in a handler's channelRead which is  after the FlowControlHandler in the pipeline. At this point if there is a thread context switch the queue may not yet contain all the expected objects and checking the queue contents is not valid.

Modifications:
- Remove checking the queues contents in FLowControlHandlerTest and instead only check the empty condition at the end of the tests

Result:
FlowControlHandlerTest won't fail due to invalid checks of the contents of the queue.

handler/src/main/java/io/netty/handler/flow/FlowControlHandler.java

@@ -87,17 +87,11 @@ public class FlowControlHandler extends ChannelDuplexHandler {
     }
 
     /**
-     * Returns a copy of the underlying {@link Queue}. This method exists for
+     * Determine if the underlying {@link Queue} is empty. This method exists for
      * testing, debugging and inspection purposes and it is not Thread safe!
      */
-    Queue<Object> queue() {
+    boolean isQueueEmpty() {
-        RecyclableArrayDeque queue = this.queue;
+        return queue.isEmpty();
-
-        if (queue == null) {
-            return new ArrayDeque<Object>(0);
-        }
-
-        return new ArrayDeque<Object>(queue);
     }
 
     /**

handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java

@@ -15,25 +15,6 @@
  */
 package io.netty.handler.flow;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
-import java.net.SocketAddress;
-import java.util.List;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Exchanger;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicReference;
-
-import org.hamcrest.collection.IsIterableContainingInOrder;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
-
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.buffer.ByteBuf;
@@ -53,6 +34,23 @@ import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.util.ReferenceCountUtil;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.net.SocketAddress;
+import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Exchanger;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class FlowControlHandlerTest {
     private static EventLoopGroup GROUP;
@@ -231,7 +229,7 @@ public class FlowControlHandlerTest {
 
             // We should receive 3 messages
             assertTrue(latch.await(1L, TimeUnit.SECONDS));
-            assertTrue(flow.queue().isEmpty());
+            assertTrue(flow.isQueueEmpty());
         } finally {
             client.close();
             server.close();
@@ -284,7 +282,6 @@ public class FlowControlHandlerTest {
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertFalse(peer.config().isAutoRead());
             assertEquals(1, counter.get());
-            assertThat(flow.queue(), IsIterableContainingInOrder.<Object>contains("2", "3"));
 
             // channelRead(2)
             latchRef.set(new CountDownLatch(1));
@@ -292,7 +289,6 @@ public class FlowControlHandlerTest {
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertFalse(peer.config().isAutoRead());
             assertEquals(2, counter.get());
-            assertThat(flow.queue(), IsIterableContainingInOrder.<Object>contains("3"));
 
             // channelRead(3)
             latchRef.set(new CountDownLatch(1));
@@ -300,7 +296,7 @@ public class FlowControlHandlerTest {
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertFalse(peer.config().isAutoRead());
             assertEquals(3, counter.get());
-            assertTrue(flow.queue().isEmpty());
+            assertTrue(flow.isQueueEmpty());
         } finally {
             client.close();
             server.close();
@@ -350,21 +346,19 @@ public class FlowControlHandlerTest {
             peer.read();
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertEquals(1, counter.get());
-            assertThat(flow.queue(), IsIterableContainingInOrder.<Object>contains("2", "3"));
 
             // channelRead(2)
             latchRef.set(new CountDownLatch(1));
             peer.read();
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertEquals(2, counter.get());
-            assertThat(flow.queue(), IsIterableContainingInOrder.<Object>contains("3"));
 
             // channelRead(3)
             latchRef.set(new CountDownLatch(1));
             peer.read();
             assertTrue(latchRef.get().await(1L, TimeUnit.SECONDS));
             assertEquals(3, counter.get());
-            assertTrue(flow.queue().isEmpty());
+            assertTrue(flow.isQueueEmpty());
         } finally {
             client.close();
             server.close();