Update //third_party/protobuf to version 3.

third_party/protobuf/java/src/test/java/com/google/protobuf/WireFormatTest.java

Index: third_party/protobuf/java/src/test/java/com/google/protobuf/WireFormatTest.java
diff --git a/third_party/protobuf/java/src/test/java/com/google/protobuf/WireFormatTest.java b/third_party/protobuf/java/src/test/java/com/google/protobuf/WireFormatTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..0175005d2ca9f844cfc52305abbcab449cbd7eb1
--- /dev/null
+++ b/third_party/protobuf/java/src/test/java/com/google/protobuf/WireFormatTest.java
@@ -0,0 +1,606 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import junit.framework.TestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.List;
+
+import protobuf_unittest.UnittestProto;
+import protobuf_unittest.UnittestProto.TestAllExtensions;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+import protobuf_unittest.UnittestProto.TestFieldOrderings;
+import protobuf_unittest.UnittestProto.TestOneof2;
+import protobuf_unittest.UnittestProto.TestOneofBackwardsCompatible;
+import protobuf_unittest.UnittestProto.TestPackedExtensions;
+import protobuf_unittest.UnittestProto.TestPackedTypes;
+import protobuf_unittest.UnittestMset.RawMessageSet;
+import protobuf_unittest.UnittestMset.TestMessageSetExtension1;
+import protobuf_unittest.UnittestMset.TestMessageSetExtension2;
+import proto2_wireformat_unittest.UnittestMsetWireFormat.TestMessageSet;
+import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
+import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
+
+/**
+ * Tests related to parsing and serialization.
+ *
+ * @author kenton@google.com (Kenton Varda)
+ */
+public class WireFormatTest extends TestCase {
+  public void testSerialization() throws Exception {
+    TestAllTypes message = TestUtil.getAllSet();
+
+    ByteString rawBytes = message.toByteString();
+    assertEquals(rawBytes.size(), message.getSerializedSize());
+
+    TestAllTypes message2 = TestAllTypes.parseFrom(rawBytes);
+
+    TestUtil.assertAllFieldsSet(message2);
+  }
+
+  public void testSerializationPacked() throws Exception {
+    TestPackedTypes message = TestUtil.getPackedSet();
+
+    ByteString rawBytes = message.toByteString();
+    assertEquals(rawBytes.size(), message.getSerializedSize());
+
+    TestPackedTypes message2 = TestPackedTypes.parseFrom(rawBytes);
+
+    TestUtil.assertPackedFieldsSet(message2);
+  }
+
+  public void testSerializeExtensions() throws Exception {
+    // TestAllTypes and TestAllExtensions should have compatible wire formats,
+    // so if we serialize a TestAllExtensions then parse it as TestAllTypes
+    // it should work.
+
+    TestAllExtensions message = TestUtil.getAllExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+    assertEquals(rawBytes.size(), message.getSerializedSize());
+
+    TestAllTypes message2 = TestAllTypes.parseFrom(rawBytes);
+
+    TestUtil.assertAllFieldsSet(message2);
+  }
+
+  public void testSerializePackedExtensions() throws Exception {
+    // TestPackedTypes and TestPackedExtensions should have compatible wire
+    // formats; check that they serialize to the same string.
+    TestPackedExtensions message = TestUtil.getPackedExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+
+    TestPackedTypes message2 = TestUtil.getPackedSet();
+    ByteString rawBytes2 = message2.toByteString();
+
+    assertEquals(rawBytes, rawBytes2);
+  }
+
+  public void testSerializationPackedWithoutGetSerializedSize()
+      throws Exception {
+    // Write directly to an OutputStream, without invoking getSerializedSize()
+    // This used to be a bug where the size of a packed field was incorrect,
+    // since getSerializedSize() was never invoked.
+    TestPackedTypes message = TestUtil.getPackedSet();
+
+    // Directly construct a CodedOutputStream around the actual OutputStream,
+    // in case writeTo(OutputStream output) invokes getSerializedSize();
+    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+    CodedOutputStream codedOutput = CodedOutputStream.newInstance(outputStream);
+
+    message.writeTo(codedOutput);
+
+    codedOutput.flush();
+
+    TestPackedTypes message2 = TestPackedTypes.parseFrom(
+        outputStream.toByteArray());
+
+    TestUtil.assertPackedFieldsSet(message2);
+  }
+
+  public void testSerializeExtensionsLite() throws Exception {
+    // TestAllTypes and TestAllExtensions should have compatible wire formats,
+    // so if we serialize a TestAllExtensions then parse it as TestAllTypes
+    // it should work.
+
+    TestAllExtensionsLite message = TestUtil.getAllLiteExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+    assertEquals(rawBytes.size(), message.getSerializedSize());
+
+    TestAllTypes message2 = TestAllTypes.parseFrom(rawBytes);
+
+    TestUtil.assertAllFieldsSet(message2);
+  }
+
+  public void testSerializePackedExtensionsLite() throws Exception {
+    // TestPackedTypes and TestPackedExtensions should have compatible wire
+    // formats; check that they serialize to the same string.
+    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+
+    TestPackedTypes message2 = TestUtil.getPackedSet();
+    ByteString rawBytes2 = message2.toByteString();
+
+    assertEquals(rawBytes, rawBytes2);
+  }
+
+  public void testParseExtensions() throws Exception {
+    // TestAllTypes and TestAllExtensions should have compatible wire formats,
+    // so if we serialize a TestAllTypes then parse it as TestAllExtensions
+    // it should work.
+
+    TestAllTypes message = TestUtil.getAllSet();
+    ByteString rawBytes = message.toByteString();
+
+    ExtensionRegistry registry = TestUtil.getExtensionRegistry();
+
+    TestAllExtensions message2 =
+      TestAllExtensions.parseFrom(rawBytes, registry);
+
+    TestUtil.assertAllExtensionsSet(message2);
+  }
+
+  public void testParsePackedExtensions() throws Exception {
+    // Ensure that packed extensions can be properly parsed.
+    TestPackedExtensions message = TestUtil.getPackedExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+
+    ExtensionRegistry registry = TestUtil.getExtensionRegistry();
+
+    TestPackedExtensions message2 =
+        TestPackedExtensions.parseFrom(rawBytes, registry);
+
+    TestUtil.assertPackedExtensionsSet(message2);
+  }
+
+  public void testParseExtensionsLite() throws Exception {
+    // TestAllTypes and TestAllExtensions should have compatible wire formats,
+    // so if we serialize a TestAllTypes then parse it as TestAllExtensions
+    // it should work.
+
+    TestAllTypes message = TestUtil.getAllSet();
+    ByteString rawBytes = message.toByteString();
+
+    ExtensionRegistryLite registry_lite = TestUtil.getExtensionRegistryLite();
+
+    TestAllExtensionsLite message2 =
+      TestAllExtensionsLite.parseFrom(rawBytes, registry_lite);
+
+    TestUtil.assertAllExtensionsSet(message2);
+
+    // Try again using a full extension registry.
+    ExtensionRegistry registry = TestUtil.getExtensionRegistry();
+
+    TestAllExtensionsLite message3 =
+      TestAllExtensionsLite.parseFrom(rawBytes, registry);
+
+    TestUtil.assertAllExtensionsSet(message3);
+  }
+
+  public void testParsePackedExtensionsLite() throws Exception {
+    // Ensure that packed extensions can be properly parsed.
+    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    ByteString rawBytes = message.toByteString();
+
+    ExtensionRegistryLite registry = TestUtil.getExtensionRegistryLite();
+
+    TestPackedExtensionsLite message2 =
+        TestPackedExtensionsLite.parseFrom(rawBytes, registry);
+
+    TestUtil.assertPackedExtensionsSet(message2);
+  }
+
+  public void testExtensionsSerializedSize() throws Exception {
+    assertNotSame(TestUtil.getAllSet().getSerializedSize(),
+                  TestUtil.getAllExtensionsSet().getSerializedSize());
+  }
+
+  public void testSerializeDelimited() throws Exception {
+    ByteArrayOutputStream output = new ByteArrayOutputStream();
+    TestUtil.getAllSet().writeDelimitedTo(output);
+    output.write(12);
+    TestUtil.getPackedSet().writeDelimitedTo(output);
+    output.write(34);
+
+    ByteArrayInputStream input = new ByteArrayInputStream(output.toByteArray());
+
+    TestUtil.assertAllFieldsSet(TestAllTypes.parseDelimitedFrom(input));
+    assertEquals(12, input.read());
+    TestUtil.assertPackedFieldsSet(TestPackedTypes.parseDelimitedFrom(input));
+    assertEquals(34, input.read());
+    assertEquals(-1, input.read());
+
+    // We're at EOF, so parsing again should return null.
+    assertTrue(TestAllTypes.parseDelimitedFrom(input) == null);
+  }
+
+  private void assertFieldsInOrder(ByteString data) throws Exception {
+    CodedInputStream input = data.newCodedInput();
+    int previousTag = 0;
+
+    while (true) {
+      int tag = input.readTag();
+      if (tag == 0) {
+        break;
+      }
+
+      assertTrue(tag > previousTag);
+      previousTag = tag;
+      input.skipField(tag);
+    }
+  }
+
+  public void testInterleavedFieldsAndExtensions() throws Exception {
+    // Tests that fields are written in order even when extension ranges
+    // are interleaved with field numbers.
+    ByteString data =
+      TestFieldOrderings.newBuilder()
+        .setMyInt(1)
+        .setMyString("foo")
+        .setMyFloat(1.0F)
+        .setExtension(UnittestProto.myExtensionInt, 23)
+        .setExtension(UnittestProto.myExtensionString, "bar")
+        .build().toByteString();
+    assertFieldsInOrder(data);
+
+    Descriptors.Descriptor descriptor = TestFieldOrderings.getDescriptor();
+    ByteString dynamic_data =
+      DynamicMessage.newBuilder(TestFieldOrderings.getDescriptor())
+        .setField(descriptor.findFieldByName("my_int"), 1L)
+        .setField(descriptor.findFieldByName("my_string"), "foo")
+        .setField(descriptor.findFieldByName("my_float"), 1.0F)
+        .setField(UnittestProto.myExtensionInt.getDescriptor(), 23)
+        .setField(UnittestProto.myExtensionString.getDescriptor(), "bar")
+        .build().toByteString();
+    assertFieldsInOrder(dynamic_data);
+  }
+
+  private ExtensionRegistry getTestFieldOrderingsRegistry() {
+    ExtensionRegistry result = ExtensionRegistry.newInstance();
+    result.add(UnittestProto.myExtensionInt);
+    result.add(UnittestProto.myExtensionString);
+    return result;
+  }
+
+  public void testParseMultipleExtensionRanges() throws Exception {
+    // Make sure we can parse a message that contains multiple extensions
+    // ranges.
+    TestFieldOrderings source =
+      TestFieldOrderings.newBuilder()
+        .setMyInt(1)
+        .setMyString("foo")
+        .setMyFloat(1.0F)
+        .setExtension(UnittestProto.myExtensionInt, 23)
+        .setExtension(UnittestProto.myExtensionString, "bar")
+        .build();
+    TestFieldOrderings dest =
+      TestFieldOrderings.parseFrom(source.toByteString(),
+                                   getTestFieldOrderingsRegistry());
+    assertEquals(source, dest);
+  }
+
+  public void testParseMultipleExtensionRangesDynamic() throws Exception {
+    // Same as above except with DynamicMessage.
+    Descriptors.Descriptor descriptor = TestFieldOrderings.getDescriptor();
+    DynamicMessage source =
+      DynamicMessage.newBuilder(TestFieldOrderings.getDescriptor())
+        .setField(descriptor.findFieldByName("my_int"), 1L)
+        .setField(descriptor.findFieldByName("my_string"), "foo")
+        .setField(descriptor.findFieldByName("my_float"), 1.0F)
+        .setField(UnittestProto.myExtensionInt.getDescriptor(), 23)
+        .setField(UnittestProto.myExtensionString.getDescriptor(), "bar")
+        .build();
+    DynamicMessage dest =
+      DynamicMessage.parseFrom(descriptor, source.toByteString(),
+                               getTestFieldOrderingsRegistry());
+    assertEquals(source, dest);
+  }
+
+  private static final int UNKNOWN_TYPE_ID = 1550055;
+  private static final int TYPE_ID_1 =
+    TestMessageSetExtension1.getDescriptor().getExtensions().get(0).getNumber();
+  private static final int TYPE_ID_2 =
+    TestMessageSetExtension2.getDescriptor().getExtensions().get(0).getNumber();
+
+  public void testSerializeMessageSetEagerly() throws Exception {
+    testSerializeMessageSetWithFlag(true);
+  }
+
+  public void testSerializeMessageSetNotEagerly() throws Exception {
+    testSerializeMessageSetWithFlag(false);
+  }
+
+  private void testSerializeMessageSetWithFlag(boolean eagerParsing)
+      throws Exception {
+    ExtensionRegistryLite.setEagerlyParseMessageSets(eagerParsing);
+    // Set up a TestMessageSet with two known messages and an unknown one.
+    TestMessageSet messageSet =
+      TestMessageSet.newBuilder()
+        .setExtension(
+          TestMessageSetExtension1.messageSetExtension,
+          TestMessageSetExtension1.newBuilder().setI(123).build())
+        .setExtension(
+          TestMessageSetExtension2.messageSetExtension,
+          TestMessageSetExtension2.newBuilder().setStr("foo").build())
+        .setUnknownFields(
+          UnknownFieldSet.newBuilder()
+            .addField(UNKNOWN_TYPE_ID,
+              UnknownFieldSet.Field.newBuilder()
+                .addLengthDelimited(ByteString.copyFromUtf8("bar"))
+                .build())
+            .build())
+        .build();
+
+    ByteString data = messageSet.toByteString();
+
+    // Parse back using RawMessageSet and check the contents.
+    RawMessageSet raw = RawMessageSet.parseFrom(data);
+
+    assertTrue(raw.getUnknownFields().asMap().isEmpty());
+
+    assertEquals(3, raw.getItemCount());
+    assertEquals(TYPE_ID_1, raw.getItem(0).getTypeId());
+    assertEquals(TYPE_ID_2, raw.getItem(1).getTypeId());
+    assertEquals(UNKNOWN_TYPE_ID, raw.getItem(2).getTypeId());
+
+    TestMessageSetExtension1 message1 =
+      TestMessageSetExtension1.parseFrom(
+        raw.getItem(0).getMessage().toByteArray());
+    assertEquals(123, message1.getI());
+
+    TestMessageSetExtension2 message2 =
+      TestMessageSetExtension2.parseFrom(
+        raw.getItem(1).getMessage().toByteArray());
+    assertEquals("foo", message2.getStr());
+
+    assertEquals("bar", raw.getItem(2).getMessage().toStringUtf8());
+  }
+
+  public void testParseMessageSetEagerly() throws Exception {
+    testParseMessageSetWithFlag(true);
+  }
+
+  public void testParseMessageSetNotEagerly()throws Exception {
+    testParseMessageSetWithFlag(false);
+  }
+
+  private void testParseMessageSetWithFlag(boolean eagerParsing)
+      throws Exception {
+    ExtensionRegistryLite.setEagerlyParseMessageSets(eagerParsing);
+    ExtensionRegistry extensionRegistry = ExtensionRegistry.newInstance();
+    extensionRegistry.add(TestMessageSetExtension1.messageSetExtension);
+    extensionRegistry.add(TestMessageSetExtension2.messageSetExtension);
+
+    // Set up a RawMessageSet with two known messages and an unknown one.
+    RawMessageSet raw =
+      RawMessageSet.newBuilder()
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(TYPE_ID_1)
+            .setMessage(
+              TestMessageSetExtension1.newBuilder()
+                .setI(123)
+                .build().toByteString())
+            .build())
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(TYPE_ID_2)
+            .setMessage(
+              TestMessageSetExtension2.newBuilder()
+                .setStr("foo")
+                .build().toByteString())
+            .build())
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(UNKNOWN_TYPE_ID)
+            .setMessage(ByteString.copyFromUtf8("bar"))
+            .build())
+        .build();
+
+    ByteString data = raw.toByteString();
+
+    // Parse as a TestMessageSet and check the contents.
+    TestMessageSet messageSet =
+      TestMessageSet.parseFrom(data, extensionRegistry);
+
+    assertEquals(123, messageSet.getExtension(
+      TestMessageSetExtension1.messageSetExtension).getI());
+    assertEquals("foo", messageSet.getExtension(
+      TestMessageSetExtension2.messageSetExtension).getStr());
+
+    // Check for unknown field with type LENGTH_DELIMITED,
+    //   number UNKNOWN_TYPE_ID, and contents "bar".
+    UnknownFieldSet unknownFields = messageSet.getUnknownFields();
+    assertEquals(1, unknownFields.asMap().size());
+    assertTrue(unknownFields.hasField(UNKNOWN_TYPE_ID));
+
+    UnknownFieldSet.Field field = unknownFields.getField(UNKNOWN_TYPE_ID);
+    assertEquals(1, field.getLengthDelimitedList().size());
+    assertEquals("bar", field.getLengthDelimitedList().get(0).toStringUtf8());
+  }
+
+  public void testParseMessageSetExtensionEagerly() throws Exception {
+    testParseMessageSetExtensionWithFlag(true);
+  }
+
+  public void testParseMessageSetExtensionNotEagerly() throws Exception {
+    testParseMessageSetExtensionWithFlag(false);
+  }
+
+  private void testParseMessageSetExtensionWithFlag(boolean eagerParsing)
+      throws Exception {
+    ExtensionRegistryLite.setEagerlyParseMessageSets(eagerParsing);
+    ExtensionRegistry extensionRegistry = ExtensionRegistry.newInstance();
+    extensionRegistry.add(TestMessageSetExtension1.messageSetExtension);
+
+    // Set up a RawMessageSet with a known messages.
+    int TYPE_ID_1 =
+        TestMessageSetExtension1
+            .getDescriptor().getExtensions().get(0).getNumber();
+    RawMessageSet raw =
+      RawMessageSet.newBuilder()
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(TYPE_ID_1)
+            .setMessage(
+              TestMessageSetExtension1.newBuilder()
+                .setI(123)
+                .build().toByteString())
+            .build())
+        .build();
+
+    ByteString data = raw.toByteString();
+
+    // Parse as a TestMessageSet and check the contents.
+    TestMessageSet messageSet =
+        TestMessageSet.parseFrom(data, extensionRegistry);
+    assertEquals(123, messageSet.getExtension(
+        TestMessageSetExtension1.messageSetExtension).getI());
+  }
+
+  public void testMergeLazyMessageSetExtensionEagerly() throws Exception {
+    testMergeLazyMessageSetExtensionWithFlag(true);
+  }
+
+  public void testMergeLazyMessageSetExtensionNotEagerly() throws Exception {
+    testMergeLazyMessageSetExtensionWithFlag(false);
+  }
+
+  private void testMergeLazyMessageSetExtensionWithFlag(boolean eagerParsing)
+      throws Exception {
+    ExtensionRegistryLite.setEagerlyParseMessageSets(eagerParsing);
+    ExtensionRegistry extensionRegistry = ExtensionRegistry.newInstance();
+    extensionRegistry.add(TestMessageSetExtension1.messageSetExtension);
+
+    // Set up a RawMessageSet with a known messages.
+    int TYPE_ID_1 =
+        TestMessageSetExtension1
+            .getDescriptor().getExtensions().get(0).getNumber();
+    RawMessageSet raw =
+      RawMessageSet.newBuilder()
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(TYPE_ID_1)
+            .setMessage(
+              TestMessageSetExtension1.newBuilder()
+                .setI(123)
+                .build().toByteString())
+            .build())
+        .build();
+
+    ByteString data = raw.toByteString();
+
+    // Parse as a TestMessageSet and store value into lazy field
+    TestMessageSet messageSet =
+        TestMessageSet.parseFrom(data, extensionRegistry);
+    // Merge lazy field check the contents.
+    messageSet =
+        messageSet.toBuilder().mergeFrom(data, extensionRegistry).build();
+    assertEquals(123, messageSet.getExtension(
+        TestMessageSetExtension1.messageSetExtension).getI());
+  }
+
+  public void testMergeMessageSetExtensionEagerly() throws Exception {
+    testMergeMessageSetExtensionWithFlag(true);
+  }
+
+  public void testMergeMessageSetExtensionNotEagerly() throws Exception {
+    testMergeMessageSetExtensionWithFlag(false);
+  }
+
+  private void testMergeMessageSetExtensionWithFlag(boolean eagerParsing)
+      throws Exception {
+    ExtensionRegistryLite.setEagerlyParseMessageSets(eagerParsing);
+    ExtensionRegistry extensionRegistry = ExtensionRegistry.newInstance();
+    extensionRegistry.add(TestMessageSetExtension1.messageSetExtension);
+
+    // Set up a RawMessageSet with a known messages.
+    int TYPE_ID_1 =
+        TestMessageSetExtension1
+            .getDescriptor().getExtensions().get(0).getNumber();
+    RawMessageSet raw =
+      RawMessageSet.newBuilder()
+        .addItem(
+          RawMessageSet.Item.newBuilder()
+            .setTypeId(TYPE_ID_1)
+            .setMessage(
+              TestMessageSetExtension1.newBuilder()
+                .setI(123)
+                .build().toByteString())
+            .build())
+        .build();
+
+    // Serialize RawMessageSet unnormally (message value before type id)
+    ByteString.CodedBuilder out = ByteString.newCodedBuilder(
+        raw.getSerializedSize());
+    CodedOutputStream output = out.getCodedOutput();
+    List<RawMessageSet.Item> items = raw.getItemList();
+    for (int i = 0; i < items.size(); i++) {
+      RawMessageSet.Item item = items.get(i);
+      output.writeTag(1, WireFormat.WIRETYPE_START_GROUP);
+      output.writeBytes(3, item.getMessage());
+      output.writeInt32(2, item.getTypeId());
+      output.writeTag(1, WireFormat.WIRETYPE_END_GROUP);
+    }
+    ByteString data = out.build();
+
+    // Merge bytes into TestMessageSet and check the contents.
+    TestMessageSet messageSet =
+        TestMessageSet.newBuilder().mergeFrom(data, extensionRegistry).build();
+    assertEquals(123, messageSet.getExtension(
+        TestMessageSetExtension1.messageSetExtension).getI());
+  }
+
+  // ================================================================
+  // oneof
+  public void testOneofWireFormat() throws Exception {
+    TestOneof2.Builder builder = TestOneof2.newBuilder();
+    TestUtil.setOneof(builder);
+    TestOneof2 message = builder.build();
+    ByteString rawBytes = message.toByteString();
+
+    assertEquals(rawBytes.size(), message.getSerializedSize());
+
+    TestOneof2 message2 = TestOneof2.parseFrom(rawBytes);
+    TestUtil.assertOneofSet(message2);
+  }
+
+  public void testOneofOnlyLastSet() throws Exception {
+    TestOneofBackwardsCompatible source = TestOneofBackwardsCompatible
+        .newBuilder().setFooInt(100).setFooString("101").build();
+
+    ByteString rawBytes = source.toByteString();
+    TestOneof2 message = TestOneof2.parseFrom(rawBytes);
+    assertFalse(message.hasFooInt());
+    assertTrue(message.hasFooString());
+  }
+}