Cleanup HTTP/2 tests for Http2FrameCodec and Http2MultiplexCodec (#8646)

Motiviation:

Http2FrameCodecTest and Http2MultiplexCodecTest were quite fragile and often not went through the whole pipeline which made testing sometimes hard and error-prone.

Modification:

- Refactor tests to have data flow through the whole pipeline and so made the test more robust (by testing the while implementation).

Result:

Easier to write tests for the codecs in the future and more robust testing in general.

Beside this it also fixes https://github.com/netty/netty/issues/6036.

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2FrameCodec.java

@@ -148,7 +148,7 @@ public class Http2FrameCodec extends Http2ConnectionHandler {
 
     private final Integer initialFlowControlWindowSize;
 
-    private ChannelHandlerContext ctx;
+    ChannelHandlerContext ctx;
 
     /** Number of buffered streams if the {@link StreamBufferingEncoder} is used. **/
     private int numBufferedStreams;

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2MultiplexCodec.java

@@ -414,28 +414,11 @@ public class Http2MultiplexCodec extends Http2FrameCodec {
         }
     }
 
-    // Allow to override for testing
+    final void flush0(ChannelHandlerContext ctx) {
-    void flush0(ChannelHandlerContext ctx) {
         flush(ctx);
     }
 
-    /**
+    static final class Http2MultiplexCodecStream extends DefaultHttp2FrameStream {
-     * Return bytes to flow control.
-     * <p>
-     * Package private to allow to override for testing
-     * @param ctx The {@link ChannelHandlerContext} associated with the parent channel.
-     * @param stream The object representing the HTTP/2 stream.
-     * @param bytes The number of bytes to return to flow control.
-     * @return {@code true} if a frame has been written as a result of this method call.
-     * @throws Http2Exception If this operation violates the flow control limits.
-     */
-    boolean onBytesConsumed(@SuppressWarnings("unused") ChannelHandlerContext ctx,
-                         Http2FrameStream stream, int bytes) throws Http2Exception {
-        return consumeBytes(stream.id(), bytes);
-    }
-
-    // Allow to extend for testing
-    static class Http2MultiplexCodecStream extends DefaultHttp2FrameStream {
         DefaultHttp2StreamChannel channel;
     }
 
@@ -1084,7 +1067,7 @@ public class Http2MultiplexCodec extends Http2FrameCodec {
                     allocHandle.lastBytesRead(numBytesToBeConsumed);
                     if (numBytesToBeConsumed != 0) {
                         try {
-                            writeDoneAndNoFlush |= onBytesConsumed(ctx, stream, numBytesToBeConsumed);
+                            writeDoneAndNoFlush |= consumeBytes(stream.id(), numBytesToBeConsumed);
                         } catch (Http2Exception e) {
                             pipeline().fireExceptionCaught(e);
                         }

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2MultiplexCodecBuilder.java

@@ -27,6 +27,7 @@ import static io.netty.util.internal.ObjectUtil.checkNotNull;
 @UnstableApi
 public class Http2MultiplexCodecBuilder
         extends AbstractHttp2ConnectionHandlerBuilder<Http2MultiplexCodec, Http2MultiplexCodecBuilder> {
+    private Http2FrameWriter frameWriter;
 
     final ChannelHandler childHandler;
     private ChannelHandler upgradeStreamHandler;
@@ -44,6 +45,12 @@ public class Http2MultiplexCodecBuilder
         return handler;
     }
 
+    // For testing only.
+    Http2MultiplexCodecBuilder frameWriter(Http2FrameWriter frameWriter) {
+        this.frameWriter = checkNotNull(frameWriter, "frameWriter");
+        return this;
+    }
+
     /**
      * Creates a builder for a HTTP/2 client.
      *
@@ -160,6 +167,28 @@ public class Http2MultiplexCodecBuilder
 
     @Override
     public Http2MultiplexCodec build() {
+        Http2FrameWriter frameWriter = this.frameWriter;
+        if (frameWriter != null) {
+            // This is to support our tests and will never be executed by the user as frameWriter(...)
+            // is package-private.
+            DefaultHttp2Connection connection = new DefaultHttp2Connection(isServer(), maxReservedStreams());
+            Long maxHeaderListSize = initialSettings().maxHeaderListSize();
+            Http2FrameReader frameReader = new DefaultHttp2FrameReader(maxHeaderListSize == null ?
+                    new DefaultHttp2HeadersDecoder(true) :
+                    new DefaultHttp2HeadersDecoder(true, maxHeaderListSize));
+
+            if (frameLogger() != null) {
+                frameWriter = new Http2OutboundFrameLogger(frameWriter, frameLogger());
+                frameReader = new Http2InboundFrameLogger(frameReader, frameLogger());
+            }
+            Http2ConnectionEncoder encoder = new DefaultHttp2ConnectionEncoder(connection, frameWriter);
+            if (encoderEnforceMaxConcurrentStreams()) {
+                encoder = new StreamBufferingEncoder(encoder);
+            }
+            Http2ConnectionDecoder decoder = new DefaultHttp2ConnectionDecoder(connection, encoder, frameReader);
+
+            return build(decoder, encoder, initialSettings());
+        }
         return super.build();
     }
 

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameCodecTest.java

@@ -15,9 +15,7 @@
 package io.netty.handler.codec.http2;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
-import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
@@ -57,6 +55,11 @@ import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static io.netty.handler.codec.http2.Http2CodecUtil.isStreamIdValid;
+import static io.netty.handler.codec.http2.Http2TestUtil.anyChannelPromise;
+import static io.netty.handler.codec.http2.Http2TestUtil.anyHttp2Settings;
+import static io.netty.handler.codec.http2.Http2TestUtil.assertEqualsAndRelease;
+import static io.netty.handler.codec.http2.Http2TestUtil.bb;
+
 import static org.hamcrest.Matchers.instanceOf;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -73,7 +76,6 @@ import static org.mockito.Mockito.anyShort;
 import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.same;
-import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
@@ -86,9 +88,10 @@ public class Http2FrameCodecTest {
     private Http2FrameWriter frameWriter;
     private Http2FrameCodec frameCodec;
     private EmbeddedChannel channel;
+
     // For injecting inbound frames
-    private Http2FrameListener frameListener;
+    private Http2FrameInboundWriter frameInboundWriter;
-    private ChannelHandlerContext http2HandlerCtx;
+
     private LastInboundHandler inboundHandler;
 
     private final Http2Headers request = new DefaultHttp2Headers()
@@ -123,29 +126,29 @@ public class Http2FrameCodecTest {
          */
         tearDown();
 
-        frameWriter = spy(new VerifiableHttp2FrameWriter());
+        frameWriter = Http2TestUtil.mockedFrameWriter();
+
         frameCodec = frameCodecBuilder.frameWriter(frameWriter).frameLogger(new Http2FrameLogger(LogLevel.TRACE))
                 .initialSettings(initialRemoteSettings).build();
-        frameListener = ((DefaultHttp2ConnectionDecoder) frameCodec.decoder())
-                .internalFrameListener();
         inboundHandler = new LastInboundHandler();
 
         channel = new EmbeddedChannel();
+        frameInboundWriter = new Http2FrameInboundWriter(channel);
         channel.connect(new InetSocketAddress(0));
         channel.pipeline().addLast(frameCodec);
         channel.pipeline().addLast(inboundHandler);
         channel.pipeline().fireChannelActive();
 
-        http2HandlerCtx = channel.pipeline().context(frameCodec);
-
         // Handshake
-        verify(frameWriter).writeSettings(eq(http2HandlerCtx),
+        verify(frameWriter).writeSettings(eqFrameCodecCtx(), anyHttp2Settings(), anyChannelPromise());
-                                          anyHttp2Settings(), anyChannelPromise());
         verifyNoMoreInteractions(frameWriter);
         channel.writeInbound(Http2CodecUtil.connectionPrefaceBuf());
-        frameListener.onSettingsRead(http2HandlerCtx, initialRemoteSettings);
+
-        verify(frameWriter).writeSettingsAck(eq(http2HandlerCtx), anyChannelPromise());
+        frameInboundWriter.writeInboundSettings(initialRemoteSettings);
-        frameListener.onSettingsAckRead(http2HandlerCtx);
+
+        verify(frameWriter).writeSettingsAck(eqFrameCodecCtx(), anyChannelPromise());
+
+        frameInboundWriter.writeInboundSettingsAck();
 
         Http2SettingsFrame settingsFrame = inboundHandler.readInbound();
         assertNotNull(settingsFrame);
@@ -153,7 +156,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void stateChanges() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 1, request, 31, true);
+        frameInboundWriter.writeInboundHeaders(1, request, 31, true);
 
         Http2Stream stream = frameCodec.connection().stream(1);
         assertNotNull(stream);
@@ -169,12 +172,12 @@ public class Http2FrameCodecTest {
         assertEquals(inboundFrame, new DefaultHttp2HeadersFrame(request, true, 31).stream(stream2));
         assertNull(inboundHandler.readInbound());
 
-        inboundHandler.writeOutbound(new DefaultHttp2HeadersFrame(response, true, 27).stream(stream2));
+        channel.writeOutbound(new DefaultHttp2HeadersFrame(response, true, 27).stream(stream2));
         verify(frameWriter).writeHeaders(
-                eq(http2HandlerCtx), eq(1), eq(response), anyInt(), anyShort(), anyBoolean(),
+                eqFrameCodecCtx(), eq(1), eq(response), anyInt(), anyShort(), anyBoolean(),
                 eq(27), eq(true), anyChannelPromise());
         verify(frameWriter, never()).writeRstStream(
-                any(ChannelHandlerContext.class), anyInt(), anyLong(), anyChannelPromise());
+                eqFrameCodecCtx(), anyInt(), anyLong(), anyChannelPromise());
 
         assertEquals(State.CLOSED, stream.state());
         event = inboundHandler.readInboundMessageOrUserEvent();
@@ -185,7 +188,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void headerRequestHeaderResponse() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 1, request, 31, true);
+        frameInboundWriter.writeInboundHeaders(1, request, 31, true);
 
         Http2Stream stream = frameCodec.connection().stream(1);
         assertNotNull(stream);
@@ -198,12 +201,12 @@ public class Http2FrameCodecTest {
         assertEquals(inboundFrame, new DefaultHttp2HeadersFrame(request, true, 31).stream(stream2));
         assertNull(inboundHandler.readInbound());
 
-        inboundHandler.writeOutbound(new DefaultHttp2HeadersFrame(response, true, 27).stream(stream2));
+        channel.writeOutbound(new DefaultHttp2HeadersFrame(response, true, 27).stream(stream2));
         verify(frameWriter).writeHeaders(
-                eq(http2HandlerCtx), eq(1), eq(response), anyInt(), anyShort(), anyBoolean(),
+                eqFrameCodecCtx(), eq(1), eq(response), anyInt(), anyShort(), anyBoolean(),
                 eq(27), eq(true), anyChannelPromise());
         verify(frameWriter, never()).writeRstStream(
-                any(ChannelHandlerContext.class), anyInt(), anyLong(), anyChannelPromise());
+                eqFrameCodecCtx(), anyInt(), anyLong(), anyChannelPromise());
 
         assertEquals(State.CLOSED, stream.state());
         assertTrue(channel.isActive());
@@ -225,7 +228,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void entityRequestEntityResponse() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 1, request, 0, false);
+        frameInboundWriter.writeInboundHeaders(1, request, 0, false);
 
         Http2Stream stream = frameCodec.connection().stream(1);
         assertNotNull(stream);
@@ -239,39 +242,35 @@ public class Http2FrameCodecTest {
         assertNull(inboundHandler.readInbound());
 
         ByteBuf hello = bb("hello");
-        frameListener.onDataRead(http2HandlerCtx, 1, hello, 31, true);
+        frameInboundWriter.writeInboundData(1, hello, 31, true);
-        // Release hello to emulate ByteToMessageDecoder
-        hello.release();
         Http2DataFrame inboundData = inboundHandler.readInbound();
         Http2DataFrame expected = new DefaultHttp2DataFrame(bb("hello"), true, 31).stream(stream2);
-        assertEquals(expected, inboundData);
+        assertEqualsAndRelease(expected, inboundData);
 
-        assertEquals(1, inboundData.refCnt());
-        expected.release();
-        inboundData.release();
         assertNull(inboundHandler.readInbound());
 
-        inboundHandler.writeOutbound(new DefaultHttp2HeadersFrame(response, false).stream(stream2));
+        channel.writeOutbound(new DefaultHttp2HeadersFrame(response, false).stream(stream2));
-        verify(frameWriter).writeHeaders(eq(http2HandlerCtx), eq(1), eq(response), anyInt(),
+        verify(frameWriter).writeHeaders(eqFrameCodecCtx(), eq(1), eq(response), anyInt(),
                                          anyShort(), anyBoolean(), eq(0), eq(false), anyChannelPromise());
 
-        inboundHandler.writeOutbound(new DefaultHttp2DataFrame(bb("world"), true, 27).stream(stream2));
+        channel.writeOutbound(new DefaultHttp2DataFrame(bb("world"), true, 27).stream(stream2));
         ArgumentCaptor<ByteBuf> outboundData = ArgumentCaptor.forClass(ByteBuf.class);
-        verify(frameWriter).writeData(eq(http2HandlerCtx), eq(1), outboundData.capture(), eq(27),
+        verify(frameWriter).writeData(eqFrameCodecCtx(), eq(1), outboundData.capture(), eq(27),
                                       eq(true), anyChannelPromise());
 
         ByteBuf bb = bb("world");
         assertEquals(bb, outboundData.getValue());
         assertEquals(1, outboundData.getValue().refCnt());
         bb.release();
-        verify(frameWriter, never()).writeRstStream(
+        outboundData.getValue().release();
-                any(ChannelHandlerContext.class), anyInt(), anyLong(), anyChannelPromise());
+
+        verify(frameWriter, never()).writeRstStream(eqFrameCodecCtx(), anyInt(), anyLong(), anyChannelPromise());
         assertTrue(channel.isActive());
     }
 
     @Test
     public void sendRstStream() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, true);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, true);
 
         Http2Stream stream = frameCodec.connection().stream(3);
         assertNotNull(stream);
@@ -285,16 +284,15 @@ public class Http2FrameCodecTest {
         assertNotNull(stream2);
         assertEquals(3, stream2.id());
 
-        inboundHandler.writeOutbound(new DefaultHttp2ResetFrame(314 /* non-standard error */).stream(stream2));
+        channel.writeOutbound(new DefaultHttp2ResetFrame(314 /* non-standard error */).stream(stream2));
-        verify(frameWriter).writeRstStream(
+        verify(frameWriter).writeRstStream(eqFrameCodecCtx(), eq(3), eq(314L), anyChannelPromise());
-                eq(http2HandlerCtx), eq(3), eq(314L), anyChannelPromise());
         assertEquals(State.CLOSED, stream.state());
         assertTrue(channel.isActive());
     }
 
     @Test
     public void receiveRstStream() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
 
         Http2Stream stream = frameCodec.connection().stream(3);
         assertNotNull(stream);
@@ -304,7 +302,7 @@ public class Http2FrameCodecTest {
         Http2HeadersFrame actualHeaders = inboundHandler.readInbound();
         assertEquals(expectedHeaders.stream(actualHeaders.stream()), actualHeaders);
 
-        frameListener.onRstStreamRead(http2HandlerCtx, 3, Http2Error.NO_ERROR.code());
+        frameInboundWriter.writeInboundRstStream(3, Http2Error.NO_ERROR.code());
 
         Http2ResetFrame expectedRst = new DefaultHttp2ResetFrame(Http2Error.NO_ERROR).stream(actualHeaders.stream());
         Http2ResetFrame actualRst = inboundHandler.readInbound();
@@ -315,8 +313,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void sendGoAway() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
-
         Http2Stream stream = frameCodec.connection().stream(3);
         assertNotNull(stream);
         assertEquals(State.OPEN, stream.state());
@@ -324,32 +321,29 @@ public class Http2FrameCodecTest {
         ByteBuf debugData = bb("debug");
         ByteBuf expected = debugData.copy();
 
-        Http2GoAwayFrame goAwayFrame = new DefaultHttp2GoAwayFrame(Http2Error.NO_ERROR.code(), debugData.slice());
+        Http2GoAwayFrame goAwayFrame = new DefaultHttp2GoAwayFrame(Http2Error.NO_ERROR.code(), debugData);
         goAwayFrame.setExtraStreamIds(2);
 
-        inboundHandler.writeOutbound(goAwayFrame);
+        channel.writeOutbound(goAwayFrame);
-        verify(frameWriter).writeGoAway(
+        verify(frameWriter).writeGoAway(eqFrameCodecCtx(), eq(7),
-                eq(http2HandlerCtx), eq(7), eq(Http2Error.NO_ERROR.code()), eq(expected), anyChannelPromise());
+                eq(Http2Error.NO_ERROR.code()), eq(expected), anyChannelPromise());
         assertEquals(1, debugData.refCnt());
         assertEquals(State.OPEN, stream.state());
         assertTrue(channel.isActive());
         expected.release();
+        debugData.release();
     }
 
     @Test
     public void receiveGoaway() throws Exception {
         ByteBuf debugData = bb("foo");
-        frameListener.onGoAwayRead(http2HandlerCtx, 2, Http2Error.NO_ERROR.code(), debugData);
+        frameInboundWriter.writeInboundGoAway(2, Http2Error.NO_ERROR.code(), debugData);
-        // Release debugData to emulate ByteToMessageDecoder
-        debugData.release();
         Http2GoAwayFrame expectedFrame = new DefaultHttp2GoAwayFrame(2, Http2Error.NO_ERROR.code(), bb("foo"));
         Http2GoAwayFrame actualFrame = inboundHandler.readInbound();
 
-        assertEquals(expectedFrame, actualFrame);
+        assertEqualsAndRelease(expectedFrame, actualFrame);
-        assertNull(inboundHandler.readInbound());
 
-        expectedFrame.release();
+        assertNull(inboundHandler.readInbound());
-        actualFrame.release();
     }
 
     @Test
@@ -383,7 +377,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void goAwayLastStreamIdOverflowed() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 5, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(5, request, 31, false);
 
         Http2Stream stream = frameCodec.connection().stream(5);
         assertNotNull(stream);
@@ -393,10 +387,10 @@ public class Http2FrameCodecTest {
         Http2GoAwayFrame goAwayFrame = new DefaultHttp2GoAwayFrame(Http2Error.NO_ERROR.code(), debugData.slice());
         goAwayFrame.setExtraStreamIds(Integer.MAX_VALUE);
 
-        inboundHandler.writeOutbound(goAwayFrame);
+        channel.writeOutbound(goAwayFrame);
         // When the last stream id computation overflows, the last stream id should just be set to 2^31 - 1.
-        verify(frameWriter).writeGoAway(eq(http2HandlerCtx), eq(Integer.MAX_VALUE), eq(Http2Error.NO_ERROR.code()),
+        verify(frameWriter).writeGoAway(eqFrameCodecCtx(), eq(Integer.MAX_VALUE),
-                                        eq(debugData), anyChannelPromise());
+                eq(Http2Error.NO_ERROR.code()), eq(debugData), anyChannelPromise());
         assertEquals(1, debugData.refCnt());
         assertEquals(State.OPEN, stream.state());
         assertTrue(channel.isActive());
@@ -404,13 +398,13 @@ public class Http2FrameCodecTest {
 
     @Test
     public void streamErrorShouldFireExceptionForInbound() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
 
         Http2Stream stream = frameCodec.connection().stream(3);
         assertNotNull(stream);
 
         StreamException streamEx = new StreamException(3, Http2Error.INTERNAL_ERROR, "foo");
-        frameCodec.onError(http2HandlerCtx, false, streamEx);
+        channel.pipeline().fireExceptionCaught(streamEx);
 
         Http2FrameStreamEvent event = inboundHandler.readInboundMessageOrUserEvent();
         assertEquals(Http2FrameStreamEvent.Type.State, event.type());
@@ -430,13 +424,13 @@ public class Http2FrameCodecTest {
 
     @Test
     public void streamErrorShouldNotFireExceptionForOutbound() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
 
         Http2Stream stream = frameCodec.connection().stream(3);
         assertNotNull(stream);
 
         StreamException streamEx = new StreamException(3, Http2Error.INTERNAL_ERROR, "foo");
-        frameCodec.onError(http2HandlerCtx, true, streamEx);
+        frameCodec.onError(frameCodec.ctx, true, streamEx);
 
         Http2FrameStreamEvent event = inboundHandler.readInboundMessageOrUserEvent();
         assertEquals(Http2FrameStreamEvent.Type.State, event.type());
@@ -452,14 +446,14 @@ public class Http2FrameCodecTest {
 
     @Test
     public void windowUpdateFrameDecrementsConsumedBytes() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
 
         Http2Connection connection = frameCodec.connection();
         Http2Stream stream = connection.stream(3);
         assertNotNull(stream);
 
         ByteBuf data = Unpooled.buffer(100).writeZero(100);
-        frameListener.onDataRead(http2HandlerCtx, 3, data, 0, true);
+        frameInboundWriter.writeInboundData(3, data, 0, false);
 
         Http2HeadersFrame inboundHeaders = inboundHandler.readInbound();
         assertNotNull(inboundHeaders);
@@ -472,12 +466,11 @@ public class Http2FrameCodecTest {
         int after = connection.local().flowController().unconsumedBytes(stream);
         assertEquals(100, before - after);
         assertTrue(f.isSuccess());
-        data.release();
     }
 
     @Test
     public void windowUpdateMayFail() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
         Http2Connection connection = frameCodec.connection();
         Http2Stream stream = connection.stream(3);
         assertNotNull(stream);
@@ -496,10 +489,10 @@ public class Http2FrameCodecTest {
 
     @Test
     public void inboundWindowUpdateShouldBeForwarded() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 31, false);
-        frameListener.onWindowUpdateRead(http2HandlerCtx, 3, 100);
+        frameInboundWriter.writeInboundWindowUpdate(3, 100);
         // Connection-level window update
-        frameListener.onWindowUpdateRead(http2HandlerCtx, 0, 100);
+        frameInboundWriter.writeInboundWindowUpdate(0, 100);
 
         Http2HeadersFrame headersFrame = inboundHandler.readInbound();
         assertNotNull(headersFrame);
@@ -558,7 +551,7 @@ public class Http2FrameCodecTest {
         unknownFrame.stream(stream);
         channel.write(unknownFrame);
 
-        verify(frameWriter).writeFrame(eq(http2HandlerCtx), eq(unknownFrame.frameType()),
+        verify(frameWriter).writeFrame(eqFrameCodecCtx(), eq(unknownFrame.frameType()),
                 eq(unknownFrame.stream().id()), eq(unknownFrame.flags()), eq(buffer), any(ChannelPromise.class));
     }
 
@@ -567,7 +560,7 @@ public class Http2FrameCodecTest {
         Http2Settings settings = new Http2Settings();
         channel.write(new DefaultHttp2SettingsFrame(settings));
 
-        verify(frameWriter).writeSettings(eq(http2HandlerCtx), same(settings), any(ChannelPromise.class));
+        verify(frameWriter).writeSettings(eqFrameCodecCtx(), same(settings), any(ChannelPromise.class));
     }
 
     @Test(timeout = 5000)
@@ -619,7 +612,7 @@ public class Http2FrameCodecTest {
         assertFalse(promise2.isDone());
 
         // Increase concurrent streams limit to 2
-        frameListener.onSettingsRead(http2HandlerCtx, new Http2Settings().maxConcurrentStreams(2));
+        frameInboundWriter.writeInboundSettings(new Http2Settings().maxConcurrentStreams(2));
 
         channel.flush();
 
@@ -643,7 +636,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void receivePing() throws Http2Exception {
-        frameListener.onPingRead(http2HandlerCtx, 12345L);
+        frameInboundWriter.writeInboundPing(false, 12345L);
 
         Http2PingFrame pingFrame = inboundHandler.readInbound();
         assertNotNull(pingFrame);
@@ -656,13 +649,13 @@ public class Http2FrameCodecTest {
     public void sendPing() {
         channel.writeAndFlush(new DefaultHttp2PingFrame(12345));
 
-        verify(frameWriter).writePing(eq(http2HandlerCtx), eq(false), eq(12345L), anyChannelPromise());
+        verify(frameWriter).writePing(eqFrameCodecCtx(), eq(false), eq(12345L), anyChannelPromise());
     }
 
     @Test
     public void receiveSettings() throws Http2Exception {
         Http2Settings settings = new Http2Settings().maxConcurrentStreams(1);
-        frameListener.onSettingsRead(http2HandlerCtx, settings);
+        frameInboundWriter.writeInboundSettings(settings);
 
         Http2SettingsFrame settingsFrame = inboundHandler.readInbound();
         assertNotNull(settingsFrame);
@@ -674,7 +667,7 @@ public class Http2FrameCodecTest {
         Http2Settings settings = new Http2Settings().maxConcurrentStreams(1);
         channel.writeAndFlush(new DefaultHttp2SettingsFrame(settings));
 
-        verify(frameWriter).writeSettings(eq(http2HandlerCtx), eq(settings), anyChannelPromise());
+        verify(frameWriter).writeSettings(eqFrameCodecCtx(), eq(settings), anyChannelPromise());
     }
 
     @Test
@@ -682,7 +675,7 @@ public class Http2FrameCodecTest {
         setUp(Http2FrameCodecBuilder.forServer().encoderEnforceMaxConcurrentStreams(true),
               new Http2Settings().maxConcurrentStreams(1));
 
-        frameListener.onHeadersRead(http2HandlerCtx, 3, request, 0, false);
+        frameInboundWriter.writeInboundHeaders(3, request, 0, false);
 
         Http2HeadersFrame headersFrame = inboundHandler.readInbound();
         assertNotNull(headersFrame);
@@ -736,8 +729,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void upgradeEventNoRefCntError() throws Exception {
-        frameListener.onHeadersRead(http2HandlerCtx, Http2CodecUtil.HTTP_UPGRADE_STREAM_ID, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(Http2CodecUtil.HTTP_UPGRADE_STREAM_ID, request, 31, false);
-
         // Using reflect as the constructor is package-private and the class is final.
         Constructor<UpgradeEvent> constructor =
                 UpgradeEvent.class.getDeclaredConstructor(CharSequence.class, FullHttpRequest.class);
@@ -753,7 +745,7 @@ public class Http2FrameCodecTest {
 
     @Test
     public void upgradeWithoutFlowControlling() throws Exception {
-        channel.pipeline().addAfter(http2HandlerCtx.name(), null, new ChannelInboundHandlerAdapter() {
+        channel.pipeline().addAfter(frameCodec.ctx.name(), null, new ChannelInboundHandlerAdapter() {
             @Override
             public void channelRead(final ChannelHandlerContext ctx, Object msg) throws Exception {
                 if (msg instanceof Http2DataFrame) {
@@ -774,7 +766,7 @@ public class Http2FrameCodecTest {
             }
         });
 
-        frameListener.onHeadersRead(http2HandlerCtx, Http2CodecUtil.HTTP_UPGRADE_STREAM_ID, request, 31, false);
+        frameInboundWriter.writeInboundHeaders(Http2CodecUtil.HTTP_UPGRADE_STREAM_ID, request, 31, false);
 
         // Using reflect as the constructor is package-private and the class is final.
         Constructor<UpgradeEvent> constructor =
@@ -792,24 +784,7 @@ public class Http2FrameCodecTest {
         channel.pipeline().fireUserEventTriggered(upgradeEvent);
     }
 
-    private static ChannelPromise anyChannelPromise() {
+    private ChannelHandlerContext eqFrameCodecCtx() {
-        return any(ChannelPromise.class);
+        return eq(frameCodec.ctx);
-    }
-
-    private static Http2Settings anyHttp2Settings() {
-        return any(Http2Settings.class);
-    }
-
-    private static ByteBuf bb(String s) {
-        return ByteBufUtil.writeUtf8(UnpooledByteBufAllocator.DEFAULT, s);
-    }
-
-    private static class VerifiableHttp2FrameWriter extends DefaultHttp2FrameWriter {
-        @Override
-        public ChannelFuture writeData(ChannelHandlerContext ctx, int streamId, ByteBuf data,
-                                       int padding, boolean endStream, ChannelPromise promise) {
-            // duplicate 'data' to prevent readerIndex from being changed, to ease verification
-            return super.writeData(ctx, streamId, data.duplicate(), padding, endStream, promise);
-        }
     }
 }

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameInboundWriter.java

@@ -0,0 +1,340 @@
+/*
+ * Copyright 2018 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.handler.codec.http2;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.ChannelProgressivePromise;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
+import io.netty.util.concurrent.EventExecutor;
+
+import java.net.SocketAddress;
+
+/**
+ * Utility class which allows easy writing of HTTP2 frames via {@link EmbeddedChannel#writeInbound(Object...)}.
+ */
+final class Http2FrameInboundWriter {
+
+    private final ChannelHandlerContext ctx;
+    private final Http2FrameWriter writer;
+
+    Http2FrameInboundWriter(EmbeddedChannel channel) {
+        this(channel, new DefaultHttp2FrameWriter());
+    }
+
+    Http2FrameInboundWriter(EmbeddedChannel channel, Http2FrameWriter writer) {
+        this.ctx = new WriteInboundChannelHandlerContext(channel);
+        this.writer = writer;
+    }
+
+    void writeInboundData(int streamId, ByteBuf data, int padding, boolean endStream) {
+        writer.writeData(ctx, streamId, data, padding, endStream, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundHeaders(int streamId, Http2Headers headers,
+                         int padding, boolean endStream) {
+        writer.writeHeaders(ctx, streamId, headers, padding, endStream, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundHeaders(int streamId, Http2Headers headers,
+                               int streamDependency, short weight, boolean exclusive, int padding, boolean endStream) {
+        writer.writeHeaders(ctx, streamId, headers, streamDependency,
+                weight, exclusive, padding, endStream, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundPriority(int streamId, int streamDependency,
+                                short weight, boolean exclusive) {
+        writer.writePriority(ctx, streamId, streamDependency, weight,
+                exclusive, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundRstStream(int streamId, long errorCode) {
+        writer.writeRstStream(ctx, streamId, errorCode, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundSettings(Http2Settings settings) {
+        writer.writeSettings(ctx, settings, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundSettingsAck() {
+        writer.writeSettingsAck(ctx, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundPing(boolean ack, long data) {
+        writer.writePing(ctx, ack, data, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writePushPromise(int streamId, int promisedStreamId,
+                                   Http2Headers headers, int padding) {
+           writer.writePushPromise(ctx, streamId, promisedStreamId,
+                   headers, padding, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundGoAway(int lastStreamId, long errorCode, ByteBuf debugData) {
+        writer.writeGoAway(ctx, lastStreamId, errorCode, debugData, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundWindowUpdate(int streamId, int windowSizeIncrement) {
+        writer.writeWindowUpdate(ctx, streamId, windowSizeIncrement, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    void writeInboundFrame(byte frameType, int streamId,
+                             Http2Flags flags, ByteBuf payload) {
+        writer.writeFrame(ctx, frameType, streamId, flags, payload, ctx.newPromise()).syncUninterruptibly();
+    }
+
+    private static final class WriteInboundChannelHandlerContext extends ChannelOutboundHandlerAdapter
+            implements ChannelHandlerContext {
+        private final EmbeddedChannel channel;
+
+        WriteInboundChannelHandlerContext(EmbeddedChannel channel) {
+            this.channel = channel;
+        }
+
+        @Override
+        public Channel channel() {
+            return channel;
+        }
+
+        @Override
+        public EventExecutor executor() {
+            return channel.eventLoop();
+        }
+
+        @Override
+        public String name() {
+            return "WriteInbound";
+        }
+
+        @Override
+        public ChannelHandler handler() {
+            return this;
+        }
+
+        @Override
+        public boolean isRemoved() {
+            return false;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelRegistered() {
+            channel.pipeline().fireChannelRegistered();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelUnregistered() {
+            channel.pipeline().fireChannelUnregistered();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelActive() {
+            channel.pipeline().fireChannelActive();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelInactive() {
+            channel.pipeline().fireChannelInactive();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireExceptionCaught(Throwable cause) {
+            channel.pipeline().fireExceptionCaught(cause);
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireUserEventTriggered(Object evt) {
+            channel.pipeline().fireUserEventTriggered(evt);
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelRead(Object msg) {
+            channel.pipeline().fireChannelRead(msg);
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelReadComplete() {
+            channel.pipeline().fireChannelReadComplete();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext fireChannelWritabilityChanged() {
+            channel.pipeline().fireChannelWritabilityChanged();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext read() {
+            channel.read();
+            return this;
+        }
+
+        @Override
+        public ChannelHandlerContext flush() {
+            channel.pipeline().fireChannelReadComplete();
+            return this;
+        }
+
+        @Override
+        public ChannelPipeline pipeline() {
+            return channel.pipeline();
+        }
+
+        @Override
+        public ByteBufAllocator alloc() {
+            return channel.alloc();
+        }
+
+        @Override
+        public <T> Attribute<T> attr(AttributeKey<T> key) {
+            return channel.attr(key);
+        }
+
+        @Override
+        public <T> boolean hasAttr(AttributeKey<T> key) {
+            return channel.hasAttr(key);
+        }
+
+        @Override
+        public ChannelFuture bind(SocketAddress localAddress) {
+            return channel.bind(localAddress);
+        }
+
+        @Override
+        public ChannelFuture connect(SocketAddress remoteAddress) {
+            return channel.connect(remoteAddress);
+        }
+
+        @Override
+        public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress) {
+            return channel.connect(remoteAddress, localAddress);
+        }
+
+        @Override
+        public ChannelFuture disconnect() {
+            return channel.disconnect();
+        }
+
+        @Override
+        public ChannelFuture close() {
+            return channel.close();
+        }
+
+        @Override
+        public ChannelFuture deregister() {
+            return channel.deregister();
+        }
+
+        @Override
+        public ChannelFuture bind(SocketAddress localAddress, ChannelPromise promise) {
+            return channel.bind(localAddress, promise);
+        }
+
+        @Override
+        public ChannelFuture connect(SocketAddress remoteAddress, ChannelPromise promise) {
+            return channel.connect(remoteAddress, promise);
+        }
+
+        @Override
+        public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
+            return channel.connect(remoteAddress, localAddress, promise);
+        }
+
+        @Override
+        public ChannelFuture disconnect(ChannelPromise promise) {
+            return channel.disconnect(promise);
+        }
+
+        @Override
+        public ChannelFuture close(ChannelPromise promise) {
+            return channel.close(promise);
+        }
+
+        @Override
+        public ChannelFuture deregister(ChannelPromise promise) {
+            return channel.deregister(promise);
+        }
+
+        @Override
+        public ChannelFuture write(Object msg) {
+            return write(msg, newPromise());
+        }
+
+        @Override
+        public ChannelFuture write(Object msg, ChannelPromise promise) {
+            return writeAndFlush(msg, promise);
+        }
+
+        @Override
+        public ChannelFuture writeAndFlush(Object msg, ChannelPromise promise) {
+            try {
+                channel.writeInbound(msg);
+                channel.runPendingTasks();
+                promise.setSuccess();
+            } catch (Throwable cause) {
+                promise.setFailure(cause);
+            }
+            return promise;
+        }
+
+        @Override
+        public ChannelFuture writeAndFlush(Object msg) {
+            return writeAndFlush(msg, newPromise());
+        }
+
+        @Override
+        public ChannelPromise newPromise() {
+            return channel.newPromise();
+        }
+
+        @Override
+        public ChannelProgressivePromise newProgressivePromise() {
+            return channel.newProgressivePromise();
+        }
+
+        @Override
+        public ChannelFuture newSucceededFuture() {
+            return channel.newSucceededFuture();
+        }
+
+        @Override
+        public ChannelFuture newFailedFuture(Throwable cause) {
+            return channel.newFailedFuture(cause);
+        }
+
+        @Override
+        public ChannelPromise voidPromise() {
+            return channel.voidPromise();
+        }
+    }
+}

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2TestUtil.java

@@ -15,7 +15,9 @@
 package io.netty.handler.codec.http2;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
+import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
@@ -24,18 +26,34 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.DefaultChannelPromise;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.util.AsciiString;
+import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.Future;
 import io.netty.util.concurrent.GenericFutureListener;
 import io.netty.util.concurrent.ImmediateEventExecutor;
 import junit.framework.AssertionFailedError;
+import org.mockito.Mockito;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
 
 import java.util.List;
 import java.util.Random;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CountDownLatch;
 
 import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_HEADER_LIST_SIZE;
 import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_HEADER_TABLE_SIZE;
+import static io.netty.util.ReferenceCountUtil.release;
 import static java.lang.Math.min;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyByte;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyShort;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.when;
 
 /**
  * Utilities for the integration tests.
@@ -506,4 +524,179 @@ public final class Http2TestUtil {
             return isWriteAllowed ? (int) min(pendingBytes, Integer.MAX_VALUE) : -1;
         }
     }
+
+    static Http2FrameWriter mockedFrameWriter() {
+        Http2FrameWriter.Configuration configuration = new Http2FrameWriter.Configuration() {
+            private final Http2HeadersEncoder.Configuration headerConfiguration =
+                    new Http2HeadersEncoder.Configuration() {
+                @Override
+                public void maxHeaderTableSize(long max)  {
+                    // NOOP
+                }
+
+                @Override
+                public long maxHeaderTableSize() {
+                    return 0;
+                }
+
+                @Override
+                public void maxHeaderListSize(long max) {
+                    // NOOP
+                }
+
+                @Override
+                public long maxHeaderListSize() {
+                    return 0;
+                }
+            };
+
+            private final Http2FrameSizePolicy policy = new Http2FrameSizePolicy() {
+                @Override
+                public void maxFrameSize(int max) {
+                    // NOOP
+                }
+
+                @Override
+                public int maxFrameSize() {
+                    return 0;
+                }
+            };
+            @Override
+            public Http2HeadersEncoder.Configuration headersConfiguration() {
+                return headerConfiguration;
+            }
+
+            @Override
+            public Http2FrameSizePolicy frameSizePolicy() {
+                return policy;
+            }
+        };
+
+        final ConcurrentLinkedQueue<ByteBuf> buffers = new ConcurrentLinkedQueue<ByteBuf>();
+
+        Http2FrameWriter frameWriter = Mockito.mock(Http2FrameWriter.class);
+        doAnswer(new Answer() {
+            @Override
+            public Object answer(InvocationOnMock invocationOnMock) {
+                for (;;) {
+                    ByteBuf buf = buffers.poll();
+                    if (buf == null) {
+                        break;
+                    }
+                    buf.release();
+                }
+                return null;
+            }
+        }).when(frameWriter).close();
+
+        when(frameWriter.configuration()).thenReturn(configuration);
+        when(frameWriter.writeSettings(any(ChannelHandlerContext.class), any(Http2Settings.class),
+                any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(2)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeSettingsAck(any(ChannelHandlerContext.class), any(ChannelPromise.class)))
+                .thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(1)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeGoAway(any(ChannelHandlerContext.class), anyInt(),
+                anyLong(), any(ByteBuf.class), any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                buffers.offer((ByteBuf) invocationOnMock.getArgument(3));
+                return ((ChannelPromise) invocationOnMock.getArgument(4)).setSuccess();
+            }
+        });
+        when(frameWriter.writeHeaders(any(ChannelHandlerContext.class), anyInt(), any(Http2Headers.class), anyInt(),
+                anyBoolean(), any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(5)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeHeaders(any(ChannelHandlerContext.class), anyInt(),
+                any(Http2Headers.class), anyInt(), anyShort(), anyBoolean(), anyInt(), anyBoolean(),
+                any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(8)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeData(any(ChannelHandlerContext.class), anyInt(), any(ByteBuf.class), anyInt(),
+                anyBoolean(), any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                buffers.offer((ByteBuf) invocationOnMock.getArgument(2));
+                return ((ChannelPromise) invocationOnMock.getArgument(5)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeRstStream(any(ChannelHandlerContext.class), anyInt(),
+                anyLong(), any(ChannelPromise.class))).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(3)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeWindowUpdate(any(ChannelHandlerContext.class), anyInt(), anyInt(),
+                any(ChannelPromise.class))).then(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(3)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writePushPromise(any(ChannelHandlerContext.class), anyInt(), anyInt(), any(Http2Headers.class),
+                anyInt(), anyChannelPromise())).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                return ((ChannelPromise) invocationOnMock.getArgument(5)).setSuccess();
+            }
+        });
+
+        when(frameWriter.writeFrame(any(ChannelHandlerContext.class), anyByte(), anyInt(), any(Http2Flags.class),
+                any(ByteBuf.class), anyChannelPromise())).thenAnswer(new Answer<ChannelFuture>() {
+            @Override
+            public ChannelFuture answer(InvocationOnMock invocationOnMock) {
+                buffers.offer((ByteBuf) invocationOnMock.getArgument(4));
+                return ((ChannelPromise) invocationOnMock.getArgument(5)).setSuccess();
+            }
+        });
+        return frameWriter;
+    }
+
+    static ChannelPromise anyChannelPromise() {
+        return any(ChannelPromise.class);
+    }
+
+    static Http2Settings anyHttp2Settings() {
+        return any(Http2Settings.class);
+    }
+
+    static ByteBuf bb(String s) {
+        return ByteBufUtil.writeUtf8(UnpooledByteBufAllocator.DEFAULT, s);
+    }
+
+    static void assertEqualsAndRelease(Http2Frame expected, Http2Frame actual) {
+        try {
+            assertEquals(expected, actual);
+        } finally {
+            release(expected);
+            release(actual);
+            // Will return -1 when not implements ReferenceCounted.
+            assertTrue(ReferenceCountUtil.refCnt(expected) <= 0);
+            assertTrue(ReferenceCountUtil.refCnt(actual) <= 0);
+        }
+    }
+
 }

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

@@ -50,9 +50,9 @@ public class TestChannelInitializer extends ChannelInitializer<Channel> {
     /**
      * Designed to read a single byte at a time to control the number of reads done at a fine granularity.
      */
-    private static final class TestNumReadsRecvByteBufAllocator implements RecvByteBufAllocator {
+    static final class TestNumReadsRecvByteBufAllocator implements RecvByteBufAllocator {
         private final AtomicInteger numReads;
-        TestNumReadsRecvByteBufAllocator(AtomicInteger numReads) {
+        private TestNumReadsRecvByteBufAllocator(AtomicInteger numReads) {
             this.numReads = numReads;
         }