HTTP/2 Unit Tests EventLoopGroup cleanup

Motivation:
The HTTP/2 unit tests are suffering from OOME on the master branch.
These unit tests allocating a large number of threads (~706 peak live) which may
be related to this memory pressure.

Modifications:
Each EventLoopGroup shutdown operation will have a `sync()` call.

Result:
Lower peek live thread count and less associated memory pressure.

codec-http2/src/test/java/io/netty/handler/codec/http2/DataCompressionHttp2Test.java

@@ -43,10 +43,12 @@ import io.netty.handler.codec.compression.ZlibWrapper;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http2.Http2TestUtil.Http2Runnable;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 import org.junit.After;
 import org.junit.Before;
@@ -134,9 +136,12 @@ public class DataCompressionHttp2Test {
             dataCapture = null;
         }
         serverChannel.close().sync();
-        sb.group().shutdownGracefully();
+        Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        sb.childGroup().shutdownGracefully();
+        Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        cb.group().shutdownGracefully();
+        Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+        serverGroup.sync();
+        serverChildGroup.sync();
+        clientGroup.sync();
         serverAdapter = null;
         clientAdapter = null;
         serverConnection = null;

codec-http2/src/test/java/io/netty/handler/codec/http2/DelegatingHttp2HttpConnectionHandlerTest.java

@@ -47,10 +47,12 @@ import io.netty.handler.codec.http.FullHttpRequest;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpRequest;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 import org.junit.After;
 import org.junit.Before;
@@ -129,9 +131,12 @@ public class DelegatingHttp2HttpConnectionHandlerTest {
             capturedData = null;
         }
         serverChannel.close().sync();
-        sb.group().shutdownGracefully();
+        Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        sb.childGroup().shutdownGracefully();
+        Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        cb.group().shutdownGracefully();
+        Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+        serverGroup.sync();
+        serverChildGroup.sync();
+        clientGroup.sync();
     }
 
     @Test

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ConnectionRoundtripTest.java

@@ -41,6 +41,7 @@ import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http2.Http2TestUtil.Http2Runnable;
 import io.netty.util.CharsetUtil;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.util.List;
@@ -122,9 +123,12 @@ public class Http2ConnectionRoundtripTest {
     @After
     public void teardown() throws Exception {
         serverChannel.close().sync();
-        sb.group().shutdownGracefully();
+        Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        sb.childGroup().shutdownGracefully();
+        Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        cb.group().shutdownGracefully();
+        Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+        serverGroup.sync();
+        serverChildGroup.sync();
+        clientGroup.sync();
     }
 
     @Test

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameRoundtripTest.java

@@ -40,10 +40,12 @@ import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http2.Http2TestUtil.Http2Runnable;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 import org.junit.After;
 import org.junit.Before;
@@ -118,9 +120,12 @@ public class Http2FrameRoundtripTest {
             capturedData.get(i).release();
         }
         serverChannel.close().sync();
-        sb.group().shutdownGracefully();
+        Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        sb.childGroup().shutdownGracefully();
+        Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        cb.group().shutdownGracefully();
+        Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+        serverGroup.sync();
+        serverChildGroup.sync();
+        clientGroup.sync();
         serverAdapter = null;
     }
 

codec-http2/src/test/java/io/netty/handler/codec/http2/InboundHttp2ToHttpAdapterTest.java

@@ -46,10 +46,12 @@ import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http2.Http2TestUtil.Http2Runnable;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 import org.junit.After;
 import org.junit.Before;
@@ -145,9 +147,12 @@ public class InboundHttp2ToHttpAdapterTest {
         cleanupCapturedRequests();
         cleanupCapturedResponses();
         serverChannel.close().sync();
-        sb.group().shutdownGracefully();
+        Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        sb.childGroup().shutdownGracefully();
+        Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-        cb.group().shutdownGracefully();
+        Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+        serverGroup.sync();
+        serverChildGroup.sync();
+        clientGroup.sync();
         clientDelegator = null;
         serverDelegator = null;
         clientChannel = null;

handler/src/test/java/io/netty/handler/ssl/JettySslEngineTest.java

@@ -19,6 +19,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assume.assumeNoException;
+import static org.mockito.Mockito.verify;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.buffer.ByteBuf;
@@ -35,6 +36,7 @@ import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 import io.netty.handler.ssl.util.SelfSignedCertificate;
 import io.netty.util.NetUtil;
+import io.netty.util.concurrent.Future;
 
 import java.net.InetSocketAddress;
 import java.security.cert.CertificateException;
@@ -51,7 +53,6 @@ import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
-import static org.mockito.Mockito.verify;
 
 public class JettySslEngineTest {
     private static final String APPLICATION_LEVEL_PROTOCOL = "my-protocol";
@@ -102,9 +103,12 @@ public class JettySslEngineTest {
     public void tearDown() throws InterruptedException {
         if (serverChannel != null) {
             serverChannel.close().sync();
-            sb.group().shutdownGracefully();
+            Future<?> serverGroup = sb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-            sb.childGroup().shutdownGracefully();
+            Future<?> serverChildGroup = sb.childGroup().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
-            cb.group().shutdownGracefully();
+            Future<?> clientGroup = cb.group().shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
+            serverGroup.sync();
+            serverChildGroup.sync();
+            clientGroup.sync();
         }
         clientChannel = null;
         serverChannel = null;