diff -r 81eb51edf2cb -r 3eae36c6baa5 test/jdk/java/net/httpclient/whitebox/jdk.incubator.httpclient/jdk/incubator/http/internal/frame/FramesDecoderTest.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/net/httpclient/whitebox/jdk.incubator.httpclient/jdk/incubator/http/internal/frame/FramesDecoderTest.java	Tue Jan 23 12:23:55 2018 +0000
@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.incubator.http.internal.frame;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import static java.lang.System.out;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.testng.Assert.*;
+
+public class FramesDecoderTest {
+
+    abstract class TestFrameProcessor implements FramesDecoder.FrameProcessor {
+        protected volatile int count;
+        public int numberOfFramesDecoded() { return count; }
+    }
+
+    /**
+     * Verifies that a ByteBuffer containing more that one frame, destined
+     * to be returned to the user's subscriber, i.e. a data frame, does not
+     * inadvertently expose the following frame ( between its limit and
+     * capacity ).
+     */
+    @Test
+    public void decodeDataFrameFollowedByAnother() throws Exception {
+        // input frames for to the decoder
+        List<ByteBuffer> data1 = List.of(ByteBuffer.wrap("XXXX".getBytes(UTF_8)));
+        DataFrame dataFrame1 = new DataFrame(1, 0, data1);
+        List<ByteBuffer> data2 = List.of(ByteBuffer.wrap("YYYY".getBytes(UTF_8)));
+        DataFrame dataFrame2 = new DataFrame(1, 0, data2);
+
+        List<ByteBuffer> buffers = new ArrayList<>();
+        FramesEncoder encoder = new FramesEncoder();
+        buffers.addAll(encoder.encodeFrame(dataFrame1));
+        buffers.addAll(encoder.encodeFrame(dataFrame2));
+
+        ByteBuffer combined = ByteBuffer.allocate(1024);
+        buffers.stream().forEach(combined::put);
+        combined.flip();
+
+        TestFrameProcessor testFrameProcessor = new TestFrameProcessor() {
+            @Override
+            public void processFrame(Http2Frame frame) throws IOException {
+                assertTrue(frame instanceof DataFrame);
+                DataFrame dataFrame = (DataFrame) frame;
+                List<ByteBuffer> list = dataFrame.getData();
+                assertEquals(list.size(), 1);
+                ByteBuffer data = list.get(0);
+                byte[] bytes = new byte[data.remaining()];
+                data.get(bytes);
+                if (count == 0) {
+                    assertEquals(new String(bytes, UTF_8), "XXXX");
+                    out.println("First data received:" + data);
+                    assertEquals(data.position(), data.limit());  // since bytes read
+                    assertEquals(data.limit(), data.capacity());
+                } else {
+                    assertEquals(new String(bytes, UTF_8), "YYYY");
+                    out.println("Second data received:" + data);
+                }
+                count++;
+            }
+        };
+        FramesDecoder decoder = new FramesDecoder(testFrameProcessor);
+
+        out.println("Sending " + combined + " to decoder: ");
+        decoder.decode(combined);
+        Assert.assertEquals(testFrameProcessor.numberOfFramesDecoded(), 2);
+    }
+
+
+    /**
+     * Verifies that a ByteBuffer containing ONLY data one frame, destined
+     * to be returned to the user's subscriber, does not restrict the capacity.
+     * The complete buffer ( all its capacity ), since no longer used by the
+     * HTTP Client, should be returned to the user.
+     */
+    @Test
+    public void decodeDataFrameEnsureNotCapped() throws Exception {
+        // input frames for to the decoder
+        List<ByteBuffer> data1 = List.of(ByteBuffer.wrap("XXXX".getBytes(UTF_8)));
+        DataFrame dataFrame1 = new DataFrame(1, 0, data1);
+
+        List<ByteBuffer> buffers = new ArrayList<>();
+        FramesEncoder encoder = new FramesEncoder();
+        buffers.addAll(encoder.encodeFrame(dataFrame1));
+
+        ByteBuffer combined = ByteBuffer.allocate(1024);
+        buffers.stream().forEach(combined::put);
+        combined.flip();
+
+        TestFrameProcessor testFrameProcessor = new TestFrameProcessor() {
+            @Override
+            public void processFrame(Http2Frame frame) throws IOException {
+                assertTrue(frame instanceof DataFrame);
+                DataFrame dataFrame = (DataFrame) frame;
+                List<ByteBuffer> list = dataFrame.getData();
+                assertEquals(list.size(), 1);
+                ByteBuffer data = list.get(0);
+                byte[] bytes = new byte[data.remaining()];
+                data.get(bytes);
+                assertEquals(new String(bytes, UTF_8), "XXXX");
+                out.println("First data received:" + data);
+                assertEquals(data.position(), data.limit());  // since bytes read
+                //assertNotEquals(data.limit(), data.capacity());
+                assertEquals(data.capacity(), 1024 - 9 /*frame header*/);
+                count++;
+            }
+        };
+        FramesDecoder decoder = new FramesDecoder(testFrameProcessor);
+
+        out.println("Sending " + combined + " to decoder: ");
+        decoder.decode(combined);
+        Assert.assertEquals(testFrameProcessor.numberOfFramesDecoded(), 1);
+    }
+}