Add another test case for channelReadComplete() suppression

Related commit:
- a41b46ff43

Motivation:

We need a test case for the commit above.

transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java

@@ -621,6 +621,44 @@ public class DefaultChannelPipelineTest {
         }
     }
 
+    /**
+     * {@link ChannelInboundHandler#channelReadComplete(ChannelHandlerContext)} should not be suppressed
+     * when a handler has just been added and thus had no chance to get the previous
+     * {@link ChannelInboundHandler#channelRead(ChannelHandlerContext, Object)}.
+     */
+    @Test
+    public void testProhibitChannelReadCompleteSuppression() throws Exception {
+        final AtomicInteger readComplete = new AtomicInteger();
+
+        EmbeddedChannel ch = new EmbeddedChannel(new ChannelInboundHandlerAdapter() {
+            @Override
+            public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+                ctx.fireChannelRead(msg);
+
+                // Add a new handler *after* channelRead() is triggered, so that
+                // the new handler does not handle channelRead() at all.
+                ctx.pipeline().addAfter(ctx.name(), "newHandler", new ChannelInboundHandlerAdapter() {
+                    @Override
+                    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
+                        readComplete.incrementAndGet();
+                    }
+                });
+            }
+
+            @Override
+            public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
+                ctx.fireChannelReadComplete();
+            }
+        });
+
+        ChannelPipeline p = ch.pipeline();
+        p.fireChannelRead(Boolean.TRUE);
+        p.fireChannelReadComplete();
+        ch.finish();
+
+        assertEquals(1, readComplete.get());
+    }
+
     @Test
     public void testChannelReadTriggered() {
         final AtomicInteger read1 = new AtomicInteger();