[#2771] Correctly handle constructing of EmbeddedChannel

Motivation:

Because of an incorrect logic in teh EmbeddedChannel constructor it is not possible to use EmbeddedChannel with a ChannelInitializer as constructor argument. This is because it adds the internal LastInboundHandler to its ChannelPipeline before it register itself to the EventLoop.

Modifications:

First register self to EventLoop before add LastInboundHandler to the ChannelPipeline.

Result:

It's now possible to use EmbeddedChannel with ChannelInitializer.

transport/src/main/java/io/netty/channel/embedded/EmbeddedChannel.java

@@ -88,8 +88,8 @@ public class EmbeddedChannel extends AbstractChannel {
             p.addLast(h);
         }
 
-        p.addLast(new LastInboundHandler());
         loop.register(this);
+        p.addLast(new LastInboundHandler());
     }
 
     @Override

transport/src/test/java/io/netty/channel/embedded/EmbeddedChannelTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel.embedded;
+
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelPipeline;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class EmbeddedChannelTest {
+
+    @Test
+    public void testConstructWithChannelInitializer() {
+        final Integer first = 1;
+        final Integer second = 2;
+
+        final ChannelHandler handler = new ChannelInboundHandlerAdapter() {
+            @Override
+            public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+                ctx.fireChannelRead(first);
+                ctx.fireChannelRead(second);
+            }
+        };
+        EmbeddedChannel channel = new EmbeddedChannel(new ChannelInitializer<Channel>() {
+            @Override
+            protected void initChannel(Channel ch) throws Exception {
+                ch.pipeline().addLast(handler);
+            }
+        });
+        ChannelPipeline pipeline = channel.pipeline();
+        Assert.assertSame(handler, pipeline.firstContext().handler());
+        Assert.assertTrue(channel.writeInbound(3));
+        Assert.assertTrue(channel.finish());
+        Assert.assertSame(first, channel.readInbound());
+        Assert.assertSame(second, channel.readInbound());
+        Assert.assertNull(channel.readInbound());
+    }
+}