diff --git a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
index 3c714139ae..229bd284dd 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
@@ -21,6 +21,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 
+import java.nio.ByteBuffer;
 import java.util.zip.CRC32;
 import java.util.zip.DataFormatException;
 import java.util.zip.Deflater;
@@ -233,15 +234,24 @@ public class JdkZlibDecoder extends ZlibDecoder {
         try {
             boolean readFooter = false;
             while (!inflater.needsInput()) {
-                byte[] outArray = decompressed.array();
                 int writerIndex = decompressed.writerIndex();
-                int outIndex = decompressed.arrayOffset() + writerIndex;
                 int writable = decompressed.writableBytes();
-                int outputLength = inflater.inflate(outArray, outIndex, writable);
+                int outputLength;
+                if (decompressed.hasArray()) {
+                    byte[] outArray = decompressed.array();
+                    int outIndex = decompressed.arrayOffset() + writerIndex;
+                    outputLength = inflater.inflate(outArray, outIndex, writable);
+                } else if (decompressed.nioBufferCount() == 1) {
+                    ByteBuffer buffer = decompressed.internalNioBuffer(writerIndex, writable);
+                    outputLength = inflater.inflate(buffer);
+                } else {
+                    throw new IllegalStateException(
+                            "Decompress buffer must have array or exactly 1 NIO buffer: " + decompressed);
+                }
                 if (outputLength > 0) {
                     decompressed.writerIndex(writerIndex + outputLength);
                     if (crc != null) {
-                        crc.update(outArray, outIndex, outputLength);
+                        crc.update(decompressed, writerIndex, outputLength);
                     }
                 } else  if (inflater.needsDictionary()) {
                     if (dictionary == null) {
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
index 4ef50a0a36..c95a4d10e0 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
@@ -25,6 +25,7 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.ChannelPromiseNotifier;
 import io.netty.util.concurrent.EventExecutor;
 
+import java.nio.ByteBuffer;
 import java.util.concurrent.TimeUnit;
 import java.util.zip.CRC32;
 import java.util.zip.Deflater;
@@ -81,6 +82,10 @@ public class JdkZlibEncoder extends ZlibEncoder {
         this(wrapper, 6);
     }
 
+    public JdkZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
+        this(wrapper, compressionLevel, false);
+    }
+
     /**
      * Creates a new zlib encoder with the specified {@code compressionLevel}
      * and the specified wrapper.
@@ -89,10 +94,12 @@ public class JdkZlibEncoder extends ZlibEncoder {
      *        {@code 1} yields the fastest compression and {@code 9} yields the
      *        best compression.  {@code 0} means no compression.  The default
      *        compression level is {@code 6}.
+     * @param preferDirectBuffers {@code true} if a direct {@link ByteBuf} should be tried to be used as target for
+     *                              decompression, or {@code false} if heap allocated {@link ByteBuf}s should be used.
      *
      * @throws CompressionException if failed to initialize zlib
      */
-    public JdkZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
+    public JdkZlibEncoder(ZlibWrapper wrapper, int compressionLevel, boolean preferDirectBuffers) {
         if (compressionLevel < 0 || compressionLevel > 9) {
             throw new IllegalArgumentException(
                     "compressionLevel: " + compressionLevel + " (expected: 0-9)");
@@ -251,7 +258,7 @@ public class JdkZlibEncoder extends ZlibEncoder {
                     // no op
             }
         }
-        return ctx.alloc().heapBuffer(sizeEstimate);
+        return ctx.alloc().buffer(sizeEstimate);
     }
 
     @Override
@@ -308,13 +315,28 @@ public class JdkZlibEncoder extends ZlibEncoder {
     }
 
     private void deflate(ByteBuf out) {
-        int numBytes;
-        do {
-            int writerIndex = out.writerIndex();
-            numBytes = deflater.deflate(
-                    out.array(), out.arrayOffset() + writerIndex, out.writableBytes(), Deflater.SYNC_FLUSH);
-            out.writerIndex(writerIndex + numBytes);
-        } while (numBytes > 0);
+        if (out.hasArray()) {
+            int numBytes;
+            do {
+                int writerIndex = out.writerIndex();
+                numBytes = deflater.deflate(
+                        out.array(), out.arrayOffset() + writerIndex, out.writableBytes(), Deflater.SYNC_FLUSH);
+                out.writerIndex(writerIndex + numBytes);
+            } while (numBytes > 0);
+        } else if (out.nioBufferCount() == 1) {
+            // Use internalNioBuffer because nioBuffer is allowed to copy,
+            // which is fine for reading but not for writing.
+            int numBytes;
+            do {
+                int writerIndex = out.writerIndex();
+                ByteBuffer buffer = out.internalNioBuffer(writerIndex, out.writableBytes());
+                numBytes = deflater.deflate(buffer, Deflater.SYNC_FLUSH);
+                out.writerIndex(writerIndex + numBytes);
+            } while (numBytes > 0);
+        } else {
+            throw new IllegalArgumentException(
+                    "Don't know how to deflate buffer without array or NIO buffer count of 1: " + out);
+        }
     }
 
     @Override
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/ZlibDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/ZlibDecoder.java
index 7a1edfe2da..0444b2e03a 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/ZlibDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/ZlibDecoder.java
@@ -29,6 +29,7 @@ public abstract class ZlibDecoder extends ByteToMessageDecoder {
      * Maximum allowed size of the decompression buffer.
      */
     protected final int maxAllocation;
+    protected final boolean preferDirect = false;
 
     /**
      * Same as {@link #ZlibDecoder(int)} with maxAllocation = 0.
@@ -63,10 +64,10 @@ public abstract class ZlibDecoder extends ByteToMessageDecoder {
     protected ByteBuf prepareDecompressBuffer(ChannelHandlerContext ctx, ByteBuf buffer, int preferredSize) {
         if (buffer == null) {
             if (maxAllocation == 0) {
-                return ctx.alloc().heapBuffer(preferredSize);
+                return ctx.alloc().buffer(preferredSize);
             }
 
-            return ctx.alloc().heapBuffer(Math.min(preferredSize, maxAllocation), maxAllocation);
+            return ctx.alloc().buffer(Math.min(preferredSize, maxAllocation), maxAllocation);
         }
 
         // this always expands the buffer if possible, even if the expansion is less than preferredSize
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/ZlibEncoder.java b/codec/src/main/java/io/netty/handler/codec/compression/ZlibEncoder.java
index b558eaa076..600be717cb 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/ZlibEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/ZlibEncoder.java
@@ -29,6 +29,10 @@ public abstract class ZlibEncoder extends MessageToByteEncoder<ByteBuf> {
         super(false);
     }
 
+    protected ZlibEncoder(boolean preferDirectBuffers) {
+        super(preferDirectBuffers);
+    }
+
     /**
      * Returns {@code true} if and only if the end of the compressed stream
      * has been reached.
diff --git a/codec/src/test/java/io/netty/handler/codec/compression/JdkZlibTest.java b/codec/src/test/java/io/netty/handler/codec/compression/JdkZlibTest.java
index fcd9dbca6c..1c8e40d805 100644
--- a/codec/src/test/java/io/netty/handler/codec/compression/JdkZlibTest.java
+++ b/codec/src/test/java/io/netty/handler/codec/compression/JdkZlibTest.java
@@ -15,37 +15,513 @@
  */
 package io.netty.handler.codec.compression;
 
+import io.netty.buffer.AbstractByteBufAllocator;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.buffer.ByteBufInputStream;
 import io.netty.buffer.Unpooled;
+import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
+import io.netty.util.internal.EmptyArrays;
 import org.apache.commons.compress.utils.IOUtils;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.Queue;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.Stream;
+import java.util.zip.DeflaterOutputStream;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
 
-import static org.junit.Assert.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 
+public class JdkZlibTest {
+    private static final byte[] BYTES_SMALL = new byte[128];
+    private static final byte[] BYTES_LARGE = new byte[1024 * 1024];
+    private static final byte[] BYTES_LARGE2 = ("<!--?xml version=\"1.0\" encoding=\"ISO-8859-1\"?-->\n" +
+            "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" " +
+            "\"https://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n" +
+            "<html xmlns=\"https://www.w3.org/1999/xhtml\" xml:lang=\"en\" lang=\"en\"><head>\n" +
+            "    <title>Apache Tomcat</title>\n" +
+            "</head>\n" +
+            '\n' +
+            "<body>\n" +
+            "<h1>It works !</h1>\n" +
+            '\n' +
+            "<p>If you're seeing this page via a web browser, it means you've setup Tomcat successfully." +
+            " Congratulations!</p>\n" +
+            " \n" +
+            "<p>This is the default Tomcat home page." +
+            " It can be found on the local filesystem at: <code>/var/lib/tomcat7/webapps/ROOT/index.html</code></p>\n" +
+            '\n' +
+            "<p>Tomcat7 veterans might be pleased to learn that this system instance of Tomcat is installed with" +
+            " <code>CATALINA_HOME</code> in <code>/usr/share/tomcat7</code> and <code>CATALINA_BASE</code> in" +
+            " <code>/var/lib/tomcat7</code>, following the rules from" +
+            " <code>/usr/share/doc/tomcat7-common/RUNNING.txt.gz</code>.</p>\n" +
+            '\n' +
+            "<p>You might consider installing the following packages, if you haven't already done so:</p>\n" +
+            '\n' +
+            "<p><b>tomcat7-docs</b>: This package installs a web application that allows to browse the Tomcat 7" +
+            " documentation locally. Once installed, you can access it by clicking <a href=\"docs/\">here</a>.</p>\n" +
+            '\n' +
+            "<p><b>tomcat7-examples</b>: This package installs a web application that allows to access the Tomcat" +
+            " 7 Servlet and JSP examples. Once installed, you can access it by clicking" +
+            " <a href=\"examples/\">here</a>.</p>\n" +
+            '\n' +
+            "<p><b>tomcat7-admin</b>: This package installs two web applications that can help managing this Tomcat" +
+            " instance. Once installed, you can access the <a href=\"manager/html\">manager webapp</a> and" +
+            " the <a href=\"host-manager/html\">host-manager webapp</a>.</p><p>\n" +
+            '\n' +
+            "</p><p>NOTE: For security reasons, using the manager webapp is restricted" +
+            " to users with role \"manager\"." +
+            " The host-manager webapp is restricted to users with role \"admin\". Users are " +
+            "defined in <code>/etc/tomcat7/tomcat-users.xml</code>.</p>\n" +
+            '\n' +
+            '\n' +
+            '\n' +
+            "</body></html>").getBytes(CharsetUtil.UTF_8);
 
-public class JdkZlibTest extends ZlibTest {
-
-    @Override
-    protected ZlibEncoder createEncoder(ZlibWrapper wrapper) {
-        return new JdkZlibEncoder(wrapper);
+    static {
+        Random rand = ThreadLocalRandom.current();
+        rand.nextBytes(BYTES_SMALL);
+        rand.nextBytes(BYTES_LARGE);
+    }
+
+    enum Data {
+        NONE(null),
+        SMALL(BYTES_SMALL),
+        LARGE(BYTES_LARGE);
+
+        final byte[] bytes;
+
+        Data(byte[] bytes) {
+            this.bytes = bytes;
+        }
+    }
+
+    enum BufferType {
+        HEAP,
+        DIRECT;
+
+        ByteBuf allocate(byte[] bytes) {
+            switch (this) {
+            case HEAP: return Unpooled.wrappedBuffer(bytes);
+            case DIRECT: return Unpooled.directBuffer(bytes.length).writeBytes(bytes);
+            }
+            return fail("Fall-through should not be possible: " + this);
+        }
+    }
+
+    protected ZlibDecoder createDecoder(ZlibWrapper wrapper) {
+        return createDecoder(wrapper, 0);
+    }
+
+    protected ZlibEncoder createEncoder(ZlibWrapper wrapper, BufferType bufferType) {
+        return new JdkZlibEncoder(wrapper, 6, bufferType == BufferType.DIRECT);
     }
 
-    @Override
     protected ZlibDecoder createDecoder(ZlibWrapper wrapper, int maxAllocation) {
         return new JdkZlibDecoder(wrapper, maxAllocation);
     }
 
-    @Test(expected = DecompressionException.class)
-    @Override
+    static Stream<Arguments> compressionConfigurations() {
+        Stream.Builder<Arguments> args = Stream.builder();
+        Data[] dataVals = Data.values();
+        BufferType[] bufferTypeVals = BufferType.values();
+        ZlibWrapper[] zlibWrappers = ZlibWrapper.values();
+        for (Data data : dataVals) {
+            for (BufferType inBuf : bufferTypeVals) {
+                for (BufferType outBuf : bufferTypeVals) {
+                    for (ZlibWrapper inputWrapper : zlibWrappers) {
+                        for (ZlibWrapper outputWrapper : zlibWrappers) {
+                            args.add(Arguments.of(data, inBuf, outBuf, inputWrapper, outputWrapper));
+                        }
+                    }
+                }
+            }
+        }
+        return args.build();
+    }
+
+    static Stream<Arguments> workingConfigurations() {
+        return compressionConfigurations().filter(JdkZlibTest::isWorkingConfiguration);
+    }
+
+    private static boolean isWorkingConfiguration(Arguments args) {
+        Object[] objs = args.get();
+        ZlibWrapper inWrap = (ZlibWrapper) objs[3];
+        ZlibWrapper outWrap = (ZlibWrapper) objs[4];
+        if (inWrap == ZlibWrapper.ZLIB_OR_NONE) {
+            return false;
+        }
+        if (inWrap == ZlibWrapper.GZIP || outWrap == ZlibWrapper.GZIP) {
+            return inWrap == outWrap;
+        }
+        if (inWrap == ZlibWrapper.NONE) {
+            return outWrap == ZlibWrapper.NONE || outWrap == ZlibWrapper.ZLIB_OR_NONE;
+        }
+        if (outWrap == ZlibWrapper.NONE) {
+            return inWrap == ZlibWrapper.NONE;
+        }
+        return true;
+    }
+
+    @ParameterizedTest
+    @MethodSource("workingConfigurations")
+    void compressionInputOutput(
+            Data data, BufferType inBuf, BufferType outBuf, ZlibWrapper inWrap, ZlibWrapper outWrap) {
+        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(inWrap, inBuf));
+        EmbeddedChannel chDecoder = new EmbeddedChannel(createDecoder(outWrap));
+        chEncoder.config().setAllocator(new UnpooledByteBufAllocator(inBuf == BufferType.DIRECT));
+        chDecoder.config().setAllocator(new UnpooledByteBufAllocator(outBuf == BufferType.DIRECT));
+
+        try {
+            if (data != Data.NONE) {
+                chEncoder.writeOutbound(inBuf.allocate(data.bytes));
+                chEncoder.flush();
+
+                for (;;) {
+                    ByteBuf deflatedData = chEncoder.readOutbound();
+                    if (deflatedData == null) {
+                        break;
+                    }
+                    chDecoder.writeInbound(deflatedData);
+                }
+
+                byte[] decompressed = new byte[data.bytes.length];
+                int offset = 0;
+                for (;;) {
+                    ByteBuf buf = chDecoder.readInbound();
+                    if (buf == null) {
+                        break;
+                    }
+                    int length = buf.readableBytes();
+                    buf.readBytes(decompressed, offset, length);
+                    offset += length;
+                    buf.release();
+                    if (offset == decompressed.length) {
+                        break;
+                    }
+                }
+                assertArrayEquals(data.bytes, decompressed);
+                assertNull(chDecoder.readInbound());
+            }
+
+            // Closing an encoder channel will generate a footer.
+            assertTrue(chEncoder.finish());
+            for (;;) {
+                Object msg = chEncoder.readOutbound();
+                if (msg == null) {
+                    break;
+                }
+                ReferenceCountUtil.release(msg);
+            }
+            // But, the footer will be decoded into nothing. It's only for validation.
+            assertFalse(chDecoder.finish());
+        } finally {
+            dispose(chEncoder);
+            dispose(chDecoder);
+        }
+    }
+
+    @Test
+    public void testGZIP2() throws Exception {
+        byte[] bytes = "message".getBytes(CharsetUtil.UTF_8);
+        ByteBuf data = Unpooled.wrappedBuffer(bytes);
+        ByteBuf deflatedData = Unpooled.wrappedBuffer(gzip(bytes));
+
+        EmbeddedChannel chDecoderGZip = new EmbeddedChannel(createDecoder(ZlibWrapper.GZIP));
+        try {
+            while (deflatedData.isReadable()) {
+                chDecoderGZip.writeInbound(deflatedData.readRetainedSlice(1));
+            }
+            deflatedData.release();
+            assertTrue(chDecoderGZip.finish());
+            ByteBuf buf = Unpooled.buffer();
+            for (;;) {
+                ByteBuf b = chDecoderGZip.readInbound();
+                if (b == null) {
+                    break;
+                }
+                buf.writeBytes(b);
+                b.release();
+            }
+            assertEquals(buf, data);
+            assertNull(chDecoderGZip.readInbound());
+            data.release();
+            buf.release();
+        } finally {
+            dispose(chDecoderGZip);
+        }
+    }
+
+    private void testCompress0(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper, ByteBuf data) throws Exception {
+        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper, BufferType.HEAP));
+        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
+
+        try {
+            chEncoder.writeOutbound(data.retain());
+            chEncoder.flush();
+            data.readerIndex(0);
+
+            for (;;) {
+                ByteBuf deflatedData = chEncoder.readOutbound();
+                if (deflatedData == null) {
+                    break;
+                }
+                chDecoderZlib.writeInbound(deflatedData);
+            }
+
+            byte[] decompressed = new byte[data.readableBytes()];
+            int offset = 0;
+            for (;;) {
+                ByteBuf buf = chDecoderZlib.readInbound();
+                if (buf == null) {
+                    break;
+                }
+                int length = buf.readableBytes();
+                buf.readBytes(decompressed, offset, length);
+                offset += length;
+                buf.release();
+                if (offset == decompressed.length) {
+                    break;
+                }
+            }
+            assertEquals(data, Unpooled.wrappedBuffer(decompressed));
+            assertNull(chDecoderZlib.readInbound());
+
+            // Closing an encoder channel will generate a footer.
+            assertTrue(chEncoder.finish());
+            for (;;) {
+                Object msg = chEncoder.readOutbound();
+                if (msg == null) {
+                    break;
+                }
+                ReferenceCountUtil.release(msg);
+            }
+            // But, the footer will be decoded into nothing. It's only for validation.
+            assertFalse(chDecoderZlib.finish());
+
+            data.release();
+        } finally {
+            dispose(chEncoder);
+            dispose(chDecoderZlib);
+        }
+    }
+
+    private void testCompressNone(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
+        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper, BufferType.HEAP));
+        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
+
+        try {
+            // Closing an encoder channel without writing anything should generate both header and footer.
+            assertTrue(chEncoder.finish());
+
+            for (;;) {
+                ByteBuf deflatedData = chEncoder.readOutbound();
+                if (deflatedData == null) {
+                    break;
+                }
+                chDecoderZlib.writeInbound(deflatedData);
+            }
+
+            // Decoder should not generate anything at all.
+            boolean decoded = false;
+            for (;;) {
+                ByteBuf buf = chDecoderZlib.readInbound();
+                if (buf == null) {
+                    break;
+                }
+
+                buf.release();
+                decoded = true;
+            }
+            assertFalse(decoded, "should decode nothing");
+
+            assertFalse(chDecoderZlib.finish());
+        } finally {
+            dispose(chEncoder);
+            dispose(chDecoderZlib);
+        }
+    }
+
+    private static void dispose(EmbeddedChannel ch) {
+        if (ch.finish()) {
+            for (;;) {
+                Object msg = ch.readInbound();
+                if (msg == null) {
+                    break;
+                }
+                ReferenceCountUtil.release(msg);
+            }
+            for (;;) {
+                Object msg = ch.readOutbound();
+                if (msg == null) {
+                    break;
+                }
+                ReferenceCountUtil.release(msg);
+            }
+        }
+    }
+
+    // Test for https://github.com/netty/netty/issues/2572
+    private void testDecompressOnly(ZlibWrapper decoderWrapper, byte[] compressed, byte[] data) throws Exception {
+        EmbeddedChannel chDecoder = new EmbeddedChannel(createDecoder(decoderWrapper));
+        chDecoder.writeInbound(Unpooled.copiedBuffer(compressed));
+        assertTrue(chDecoder.finish());
+
+        ByteBuf decoded = Unpooled.buffer(data.length);
+
+        for (;;) {
+            ByteBuf buf = chDecoder.readInbound();
+            if (buf == null) {
+                break;
+            }
+            decoded.writeBytes(buf);
+            buf.release();
+        }
+        assertEquals(Unpooled.copiedBuffer(data), decoded);
+        decoded.release();
+    }
+
+    private void testCompressSmall(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
+        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_SMALL));
+        testCompress0(encoderWrapper, decoderWrapper,
+                Unpooled.directBuffer(BYTES_SMALL.length).writeBytes(BYTES_SMALL));
+    }
+
+    private void testCompressLarge(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
+        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_LARGE));
+        testCompress0(encoderWrapper, decoderWrapper,
+                Unpooled.directBuffer(BYTES_LARGE.length).writeBytes(BYTES_LARGE));
+    }
+
+    @Test
+    public void testZLIB() throws Exception {
+        testCompressNone(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
+        testCompressSmall(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
+        testCompressLarge(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
+        testDecompressOnly(ZlibWrapper.ZLIB, deflate(BYTES_LARGE2), BYTES_LARGE2);
+    }
+
+    @Test
+    public void testNONE() throws Exception {
+        testCompressNone(ZlibWrapper.NONE, ZlibWrapper.NONE);
+        testCompressSmall(ZlibWrapper.NONE, ZlibWrapper.NONE);
+        testCompressLarge(ZlibWrapper.NONE, ZlibWrapper.NONE);
+    }
+
+    @Test
+    public void testGZIP() throws Exception {
+        testCompressNone(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
+        testCompressSmall(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
+        testCompressLarge(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
+        testDecompressOnly(ZlibWrapper.GZIP, gzip(BYTES_LARGE2), BYTES_LARGE2);
+    }
+
+    @Test
+    public void testGZIPCompressOnly() throws Exception {
+        testGZIPCompressOnly0(null); // Do not write anything; just finish the stream.
+        testGZIPCompressOnly0(EmptyArrays.EMPTY_BYTES); // Write an empty array.
+        testGZIPCompressOnly0(BYTES_SMALL);
+        testGZIPCompressOnly0(BYTES_LARGE);
+    }
+
+    private void testGZIPCompressOnly0(byte[] data) throws IOException {
+        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(ZlibWrapper.GZIP, BufferType.HEAP));
+        if (data != null) {
+            chEncoder.writeOutbound(Unpooled.wrappedBuffer(data));
+        }
+        assertTrue(chEncoder.finish());
+
+        ByteBuf encoded = Unpooled.buffer();
+        for (;;) {
+            ByteBuf buf = chEncoder.readOutbound();
+            if (buf == null) {
+                break;
+            }
+            encoded.writeBytes(buf);
+            buf.release();
+        }
+
+        ByteBuf decoded = Unpooled.buffer();
+        GZIPInputStream stream = new GZIPInputStream(new ByteBufInputStream(encoded, true));
+        try {
+            byte[] buf = new byte[8192];
+            for (;;) {
+                int readBytes = stream.read(buf);
+                if (readBytes < 0) {
+                    break;
+                }
+                decoded.writeBytes(buf, 0, readBytes);
+            }
+        } finally {
+            stream.close();
+        }
+
+        if (data != null) {
+            assertEquals(Unpooled.wrappedBuffer(data), decoded);
+        } else {
+            assertFalse(decoded.isReadable());
+        }
+
+        decoded.release();
+    }
+
+    @Test
+    public void testZLIB_OR_NONE() throws Exception {
+        testCompressNone(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
+        testCompressSmall(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
+        testCompressLarge(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
+    }
+
+    @Test
+    public void testZLIB_OR_NONE2() throws Exception {
+        testCompressNone(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
+        testCompressSmall(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
+        testCompressLarge(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
+    }
+
+    @Test
     public void testZLIB_OR_NONE3() throws Exception {
-        super.testZLIB_OR_NONE3();
+        assertThrows(DecompressionException.class, () -> testCompressNone(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE));
+        assertThrows(DecompressionException.class, () -> testCompressSmall(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE));
+        assertThrows(DecompressionException.class, () -> testCompressLarge(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE));
+    }
+
+    @Test
+    public void testMaxAllocation() throws Exception {
+        int maxAllocation = 1024;
+        ZlibDecoder decoder = createDecoder(ZlibWrapper.ZLIB, maxAllocation);
+        EmbeddedChannel chDecoder = new EmbeddedChannel(decoder);
+        TestByteBufAllocator alloc = new TestByteBufAllocator(chDecoder.alloc());
+        chDecoder.config().setAllocator(alloc);
+
+        try {
+            chDecoder.writeInbound(Unpooled.wrappedBuffer(deflate(BYTES_LARGE)));
+            fail("decompressed size > maxAllocation, so should have thrown exception");
+        } catch (DecompressionException e) {
+            assertTrue(e.getMessage().startsWith("Decompression buffer has reached maximum size"));
+            assertEquals(maxAllocation, alloc.getMaxAllocation());
+            assertTrue(decoder.isClosed());
+            assertFalse(chDecoder.finish());
+        }
     }
 
     @Test
@@ -120,4 +596,50 @@ public class JdkZlibTest extends ZlibTest {
             chDecoderGZip.close();
         }
     }
+
+    private static byte[] gzip(byte[] bytes) throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        GZIPOutputStream stream = new GZIPOutputStream(out);
+        stream.write(bytes);
+        stream.close();
+        return out.toByteArray();
+    }
+
+    private static byte[] deflate(byte[] bytes) throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        OutputStream stream = new DeflaterOutputStream(out);
+        stream.write(bytes);
+        stream.close();
+        return out.toByteArray();
+    }
+
+    private static final class TestByteBufAllocator extends AbstractByteBufAllocator {
+        private final ByteBufAllocator wrapped;
+        private int maxAllocation;
+
+        TestByteBufAllocator(ByteBufAllocator wrapped) {
+            this.wrapped = wrapped;
+        }
+
+        public int getMaxAllocation() {
+            return maxAllocation;
+        }
+
+        @Override
+        public boolean isDirectBufferPooled() {
+            return wrapped.isDirectBufferPooled();
+        }
+
+        @Override
+        protected ByteBuf newHeapBuffer(int initialCapacity, int maxCapacity) {
+            maxAllocation = Math.max(maxAllocation, maxCapacity);
+            return wrapped.heapBuffer(initialCapacity, maxCapacity);
+        }
+
+        @Override
+        protected ByteBuf newDirectBuffer(int initialCapacity, int maxCapacity) {
+            maxAllocation = Math.max(maxAllocation, maxCapacity);
+            return wrapped.directBuffer(initialCapacity, maxCapacity);
+        }
+    }
 }
diff --git a/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java b/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java
deleted file mode 100644
index dbd091488a..0000000000
--- a/codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java
+++ /dev/null
@@ -1,429 +0,0 @@
-/*
- * Copyright 2013 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:
- *
- *   https://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.compression;
-
-import io.netty.buffer.AbstractByteBufAllocator;
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufAllocator;
-import io.netty.buffer.ByteBufInputStream;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.util.CharsetUtil;
-import io.netty.util.ReferenceCountUtil;
-import io.netty.util.internal.EmptyArrays;
-import org.junit.Test;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.util.Random;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.zip.DeflaterOutputStream;
-import java.util.zip.GZIPInputStream;
-import java.util.zip.GZIPOutputStream;
-
-import static org.junit.Assert.*;
-
-public abstract class ZlibTest {
-
-    private static final byte[] BYTES_SMALL = new byte[128];
-    private static final byte[] BYTES_LARGE = new byte[1024 * 1024];
-    private static final byte[] BYTES_LARGE2 = ("<!--?xml version=\"1.0\" encoding=\"ISO-8859-1\"?-->\n" +
-            "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" " +
-            "\"https://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n" +
-            "<html xmlns=\"https://www.w3.org/1999/xhtml\" xml:lang=\"en\" lang=\"en\"><head>\n" +
-            "    <title>Apache Tomcat</title>\n" +
-            "</head>\n" +
-            '\n' +
-            "<body>\n" +
-            "<h1>It works !</h1>\n" +
-            '\n' +
-            "<p>If you're seeing this page via a web browser, it means you've setup Tomcat successfully." +
-            " Congratulations!</p>\n" +
-            " \n" +
-            "<p>This is the default Tomcat home page." +
-            " It can be found on the local filesystem at: <code>/var/lib/tomcat7/webapps/ROOT/index.html</code></p>\n" +
-            '\n' +
-            "<p>Tomcat7 veterans might be pleased to learn that this system instance of Tomcat is installed with" +
-            " <code>CATALINA_HOME</code> in <code>/usr/share/tomcat7</code> and <code>CATALINA_BASE</code> in" +
-            " <code>/var/lib/tomcat7</code>, following the rules from" +
-            " <code>/usr/share/doc/tomcat7-common/RUNNING.txt.gz</code>.</p>\n" +
-            '\n' +
-            "<p>You might consider installing the following packages, if you haven't already done so:</p>\n" +
-            '\n' +
-            "<p><b>tomcat7-docs</b>: This package installs a web application that allows to browse the Tomcat 7" +
-            " documentation locally. Once installed, you can access it by clicking <a href=\"docs/\">here</a>.</p>\n" +
-            '\n' +
-            "<p><b>tomcat7-examples</b>: This package installs a web application that allows to access the Tomcat" +
-            " 7 Servlet and JSP examples. Once installed, you can access it by clicking" +
-            " <a href=\"examples/\">here</a>.</p>\n" +
-            '\n' +
-            "<p><b>tomcat7-admin</b>: This package installs two web applications that can help managing this Tomcat" +
-            " instance. Once installed, you can access the <a href=\"manager/html\">manager webapp</a> and" +
-            " the <a href=\"host-manager/html\">host-manager webapp</a>.</p><p>\n" +
-            '\n' +
-            "</p><p>NOTE: For security reasons, using the manager webapp is restricted" +
-            " to users with role \"manager\"." +
-            " The host-manager webapp is restricted to users with role \"admin\". Users are " +
-            "defined in <code>/etc/tomcat7/tomcat-users.xml</code>.</p>\n" +
-            '\n' +
-            '\n' +
-            '\n' +
-            "</body></html>").getBytes(CharsetUtil.UTF_8);
-
-    static {
-        Random rand = ThreadLocalRandom.current();
-        rand.nextBytes(BYTES_SMALL);
-        rand.nextBytes(BYTES_LARGE);
-    }
-
-    protected ZlibDecoder createDecoder(ZlibWrapper wrapper) {
-        return createDecoder(wrapper, 0);
-    }
-
-    protected abstract ZlibEncoder createEncoder(ZlibWrapper wrapper);
-    protected abstract ZlibDecoder createDecoder(ZlibWrapper wrapper, int maxAllocation);
-
-    @Test
-    public void testGZIP2() throws Exception {
-        byte[] bytes = "message".getBytes(CharsetUtil.UTF_8);
-        ByteBuf data = Unpooled.wrappedBuffer(bytes);
-        ByteBuf deflatedData = Unpooled.wrappedBuffer(gzip(bytes));
-
-        EmbeddedChannel chDecoderGZip = new EmbeddedChannel(createDecoder(ZlibWrapper.GZIP));
-        try {
-            while (deflatedData.isReadable()) {
-                chDecoderGZip.writeInbound(deflatedData.readRetainedSlice(1));
-            }
-            deflatedData.release();
-            assertTrue(chDecoderGZip.finish());
-            ByteBuf buf = Unpooled.buffer();
-            for (;;) {
-                ByteBuf b = chDecoderGZip.readInbound();
-                if (b == null) {
-                    break;
-                }
-                buf.writeBytes(b);
-                b.release();
-            }
-            assertEquals(buf, data);
-            assertNull(chDecoderGZip.readInbound());
-            data.release();
-            buf.release();
-        } finally {
-            dispose(chDecoderGZip);
-        }
-    }
-
-    private void testCompress0(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper, ByteBuf data) throws Exception {
-        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper));
-        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
-
-        try {
-            chEncoder.writeOutbound(data.retain());
-            chEncoder.flush();
-            data.readerIndex(0);
-
-            for (;;) {
-                ByteBuf deflatedData = chEncoder.readOutbound();
-                if (deflatedData == null) {
-                    break;
-                }
-                chDecoderZlib.writeInbound(deflatedData);
-            }
-
-            byte[] decompressed = new byte[data.readableBytes()];
-            int offset = 0;
-            for (;;) {
-                ByteBuf buf = chDecoderZlib.readInbound();
-                if (buf == null) {
-                    break;
-                }
-                int length = buf.readableBytes();
-                buf.readBytes(decompressed, offset, length);
-                offset += length;
-                buf.release();
-                if (offset == decompressed.length) {
-                    break;
-                }
-            }
-            assertEquals(data, Unpooled.wrappedBuffer(decompressed));
-            assertNull(chDecoderZlib.readInbound());
-
-            // Closing an encoder channel will generate a footer.
-            assertTrue(chEncoder.finish());
-            for (;;) {
-                Object msg = chEncoder.readOutbound();
-                if (msg == null) {
-                    break;
-                }
-                ReferenceCountUtil.release(msg);
-            }
-            // But, the footer will be decoded into nothing. It's only for validation.
-            assertFalse(chDecoderZlib.finish());
-
-            data.release();
-        } finally {
-            dispose(chEncoder);
-            dispose(chDecoderZlib);
-        }
-    }
-
-    private void testCompressNone(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
-        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper));
-        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
-
-        try {
-            // Closing an encoder channel without writing anything should generate both header and footer.
-            assertTrue(chEncoder.finish());
-
-            for (;;) {
-                ByteBuf deflatedData = chEncoder.readOutbound();
-                if (deflatedData == null) {
-                    break;
-                }
-                chDecoderZlib.writeInbound(deflatedData);
-            }
-
-            // Decoder should not generate anything at all.
-            boolean decoded = false;
-            for (;;) {
-                ByteBuf buf = chDecoderZlib.readInbound();
-                if (buf == null) {
-                    break;
-                }
-
-                buf.release();
-                decoded = true;
-            }
-            assertFalse("should decode nothing", decoded);
-
-            assertFalse(chDecoderZlib.finish());
-        } finally {
-            dispose(chEncoder);
-            dispose(chDecoderZlib);
-        }
-    }
-
-    private static void dispose(EmbeddedChannel ch) {
-        if (ch.finish()) {
-            for (;;) {
-                Object msg = ch.readInbound();
-                if (msg == null) {
-                    break;
-                }
-                ReferenceCountUtil.release(msg);
-            }
-            for (;;) {
-                Object msg = ch.readOutbound();
-                if (msg == null) {
-                    break;
-                }
-                ReferenceCountUtil.release(msg);
-            }
-        }
-    }
-
-    // Test for https://github.com/netty/netty/issues/2572
-    private void testDecompressOnly(ZlibWrapper decoderWrapper, byte[] compressed, byte[] data) throws Exception {
-        EmbeddedChannel chDecoder = new EmbeddedChannel(createDecoder(decoderWrapper));
-        chDecoder.writeInbound(Unpooled.copiedBuffer(compressed));
-        assertTrue(chDecoder.finish());
-
-        ByteBuf decoded = Unpooled.buffer(data.length);
-
-        for (;;) {
-            ByteBuf buf = chDecoder.readInbound();
-            if (buf == null) {
-                break;
-            }
-            decoded.writeBytes(buf);
-            buf.release();
-        }
-        assertEquals(Unpooled.copiedBuffer(data), decoded);
-        decoded.release();
-    }
-
-    private void testCompressSmall(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
-        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_SMALL));
-        testCompress0(encoderWrapper, decoderWrapper,
-                Unpooled.directBuffer(BYTES_SMALL.length).writeBytes(BYTES_SMALL));
-    }
-
-    private void testCompressLarge(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
-        testCompress0(encoderWrapper, decoderWrapper, Unpooled.wrappedBuffer(BYTES_LARGE));
-        testCompress0(encoderWrapper, decoderWrapper,
-                Unpooled.directBuffer(BYTES_LARGE.length).writeBytes(BYTES_LARGE));
-    }
-
-    @Test
-    public void testZLIB() throws Exception {
-        testCompressNone(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
-        testCompressSmall(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
-        testCompressLarge(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB);
-        testDecompressOnly(ZlibWrapper.ZLIB, deflate(BYTES_LARGE2), BYTES_LARGE2);
-    }
-
-    @Test
-    public void testNONE() throws Exception {
-        testCompressNone(ZlibWrapper.NONE, ZlibWrapper.NONE);
-        testCompressSmall(ZlibWrapper.NONE, ZlibWrapper.NONE);
-        testCompressLarge(ZlibWrapper.NONE, ZlibWrapper.NONE);
-    }
-
-    @Test
-    public void testGZIP() throws Exception {
-        testCompressNone(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
-        testCompressSmall(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
-        testCompressLarge(ZlibWrapper.GZIP, ZlibWrapper.GZIP);
-        testDecompressOnly(ZlibWrapper.GZIP, gzip(BYTES_LARGE2), BYTES_LARGE2);
-    }
-
-    @Test
-    public void testGZIPCompressOnly() throws Exception {
-        testGZIPCompressOnly0(null); // Do not write anything; just finish the stream.
-        testGZIPCompressOnly0(EmptyArrays.EMPTY_BYTES); // Write an empty array.
-        testGZIPCompressOnly0(BYTES_SMALL);
-        testGZIPCompressOnly0(BYTES_LARGE);
-    }
-
-    private void testGZIPCompressOnly0(byte[] data) throws IOException {
-        EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(ZlibWrapper.GZIP));
-        if (data != null) {
-            chEncoder.writeOutbound(Unpooled.wrappedBuffer(data));
-        }
-        assertTrue(chEncoder.finish());
-
-        ByteBuf encoded = Unpooled.buffer();
-        for (;;) {
-            ByteBuf buf = chEncoder.readOutbound();
-            if (buf == null) {
-                break;
-            }
-            encoded.writeBytes(buf);
-            buf.release();
-        }
-
-        ByteBuf decoded = Unpooled.buffer();
-        GZIPInputStream stream = new GZIPInputStream(new ByteBufInputStream(encoded, true));
-        try {
-            byte[] buf = new byte[8192];
-            for (;;) {
-                int readBytes = stream.read(buf);
-                if (readBytes < 0) {
-                    break;
-                }
-                decoded.writeBytes(buf, 0, readBytes);
-            }
-        } finally {
-            stream.close();
-        }
-
-        if (data != null) {
-            assertEquals(Unpooled.wrappedBuffer(data), decoded);
-        } else {
-            assertFalse(decoded.isReadable());
-        }
-
-        decoded.release();
-    }
-
-    @Test
-    public void testZLIB_OR_NONE() throws Exception {
-        testCompressNone(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressSmall(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressLarge(ZlibWrapper.NONE, ZlibWrapper.ZLIB_OR_NONE);
-    }
-
-    @Test
-    public void testZLIB_OR_NONE2() throws Exception {
-        testCompressNone(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressSmall(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressLarge(ZlibWrapper.ZLIB, ZlibWrapper.ZLIB_OR_NONE);
-    }
-
-    @Test
-    public void testZLIB_OR_NONE3() throws Exception {
-        testCompressNone(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressSmall(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE);
-        testCompressLarge(ZlibWrapper.GZIP, ZlibWrapper.ZLIB_OR_NONE);
-    }
-
-    @Test
-    public void testMaxAllocation() throws Exception {
-        int maxAllocation = 1024;
-        ZlibDecoder decoder = createDecoder(ZlibWrapper.ZLIB, maxAllocation);
-        EmbeddedChannel chDecoder = new EmbeddedChannel(decoder);
-        TestByteBufAllocator alloc = new TestByteBufAllocator(chDecoder.alloc());
-        chDecoder.config().setAllocator(alloc);
-
-        try {
-            chDecoder.writeInbound(Unpooled.wrappedBuffer(deflate(BYTES_LARGE)));
-            fail("decompressed size > maxAllocation, so should have thrown exception");
-        } catch (DecompressionException e) {
-            assertTrue(e.getMessage().startsWith("Decompression buffer has reached maximum size"));
-            assertEquals(maxAllocation, alloc.getMaxAllocation());
-            assertTrue(decoder.isClosed());
-            assertFalse(chDecoder.finish());
-        }
-    }
-
-    private static byte[] gzip(byte[] bytes) throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        GZIPOutputStream stream = new GZIPOutputStream(out);
-        stream.write(bytes);
-        stream.close();
-        return out.toByteArray();
-    }
-
-    private static byte[] deflate(byte[] bytes) throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        OutputStream stream = new DeflaterOutputStream(out);
-        stream.write(bytes);
-        stream.close();
-        return out.toByteArray();
-    }
-
-    private static final class TestByteBufAllocator extends AbstractByteBufAllocator {
-        private ByteBufAllocator wrapped;
-        private int maxAllocation;
-
-        TestByteBufAllocator(ByteBufAllocator wrapped) {
-            this.wrapped = wrapped;
-        }
-
-        public int getMaxAllocation() {
-            return maxAllocation;
-        }
-
-        @Override
-        public boolean isDirectBufferPooled() {
-            return wrapped.isDirectBufferPooled();
-        }
-
-        @Override
-        protected ByteBuf newHeapBuffer(int initialCapacity, int maxCapacity) {
-            maxAllocation = Math.max(maxAllocation, maxCapacity);
-            return wrapped.heapBuffer(initialCapacity, maxCapacity);
-        }
-
-        @Override
-        protected ByteBuf newDirectBuffer(int initialCapacity, int maxCapacity) {
-            maxAllocation = Math.max(maxAllocation, maxCapacity);
-            return wrapped.directBuffer(initialCapacity, maxCapacity);
-        }
-    }
-}
diff --git a/pom.xml b/pom.xml
index ce859d7838..4133e2b10b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -604,6 +604,12 @@
         <version>${junit.version}</version>
         <scope>test</scope>
       </dependency>
+      <dependency>
+        <groupId>org.junit.jupiter</groupId>
+        <artifactId>junit-jupiter-params</artifactId>
+        <version>${junit.version}</version>
+        <scope>test</scope>
+      </dependency>
       <dependency>
         <groupId>org.junit.vintage</groupId>
         <artifactId>junit-vintage-engine</artifactId>
@@ -729,6 +735,11 @@
       <artifactId>junit-jupiter-engine</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-params</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.junit.vintage</groupId>
       <artifactId>junit-vintage-engine</artifactId>