text: // 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.
  
  #include <string>
  
  #include <google/protobuf/unittest_no_field_presence.pb.h>
  #include <google/protobuf/unittest.pb.h>
  #include <google/protobuf/descriptor.pb.h>
  #include <google/protobuf/descriptor.h>
  #include <gtest/gtest.h>
  
  namespace google {
  namespace protobuf {
  namespace {
  
  // Helper: checks that all fields have default (zero/empty) values.
  void CheckDefaultValues(
      const proto2_nofieldpresence_unittest::TestAllTypes& m) {
    EXPECT_EQ(0, m.optional_int32());
    EXPECT_EQ(0, m.optional_int64());
    EXPECT_EQ(0, m.optional_uint32());
    EXPECT_EQ(0, m.optional_uint64());
    EXPECT_EQ(0, m.optional_sint32());
    EXPECT_EQ(0, m.optional_sint64());
    EXPECT_EQ(0, m.optional_fixed32());
    EXPECT_EQ(0, m.optional_fixed64());
    EXPECT_EQ(0, m.optional_sfixed32());
    EXPECT_EQ(0, m.optional_sfixed64());
    EXPECT_EQ(0, m.optional_float());
    EXPECT_EQ(0, m.optional_double());
    EXPECT_EQ(false, m.optional_bool());
    EXPECT_EQ(0, m.optional_string().size());
    EXPECT_EQ(0, m.optional_bytes().size());
  
    EXPECT_EQ(false, m.has_optional_nested_message());
    // accessor for message fields returns default instance when not present
    EXPECT_EQ(0, m.optional_nested_message().bb());
    EXPECT_EQ(false, m.has_optional_proto2_message());
    // Embedded proto2 messages still have proto2 semantics, e.g. non-zero default
    // values. Here the submessage is not present but its accessor returns the
    // default instance.
    EXPECT_EQ(41, m.optional_proto2_message().default_int32());
    EXPECT_EQ(false, m.has_optional_foreign_message());
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_FOO,
              m.optional_nested_enum());
    EXPECT_EQ(proto2_nofieldpresence_unittest::FOREIGN_FOO,
              m.optional_foreign_enum());
  
  
    EXPECT_EQ(0, m.repeated_int32_size());
    EXPECT_EQ(0, m.repeated_int64_size());
    EXPECT_EQ(0, m.repeated_uint32_size());
    EXPECT_EQ(0, m.repeated_uint64_size());
    EXPECT_EQ(0, m.repeated_sint32_size());
    EXPECT_EQ(0, m.repeated_sint64_size());
    EXPECT_EQ(0, m.repeated_fixed32_size());
    EXPECT_EQ(0, m.repeated_fixed64_size());
    EXPECT_EQ(0, m.repeated_sfixed32_size());
    EXPECT_EQ(0, m.repeated_sfixed64_size());
    EXPECT_EQ(0, m.repeated_float_size());
    EXPECT_EQ(0, m.repeated_double_size());
    EXPECT_EQ(0, m.repeated_bool_size());
    EXPECT_EQ(0, m.repeated_string_size());
    EXPECT_EQ(0, m.repeated_bytes_size());
    EXPECT_EQ(0, m.repeated_nested_message_size());
    EXPECT_EQ(0, m.repeated_foreign_message_size());
    EXPECT_EQ(0, m.repeated_proto2_message_size());
    EXPECT_EQ(0, m.repeated_nested_enum_size());
    EXPECT_EQ(0, m.repeated_foreign_enum_size());
    EXPECT_EQ(0, m.repeated_lazy_message_size());
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes::ONEOF_FIELD_NOT_SET,
              m.oneof_field_case());
  }
  
  void FillValues(proto2_nofieldpresence_unittest::TestAllTypes* m) {
    m->set_optional_int32(100);
    m->set_optional_int64(101);
    m->set_optional_uint32(102);
    m->set_optional_uint64(103);
    m->set_optional_sint32(104);
    m->set_optional_sint64(105);
    m->set_optional_fixed32(106);
    m->set_optional_fixed64(107);
    m->set_optional_sfixed32(108);
    m->set_optional_sfixed64(109);
    m->set_optional_float(110.0);
    m->set_optional_double(111.0);
    m->set_optional_bool(true);
    m->set_optional_string("asdf");
    m->set_optional_bytes("jkl;");
    m->mutable_optional_nested_message()->set_bb(42);
    m->mutable_optional_foreign_message()->set_c(43);
    m->mutable_optional_proto2_message()->set_optional_int32(44);
    m->set_optional_nested_enum(
        proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_BAZ);
    m->set_optional_foreign_enum(
        proto2_nofieldpresence_unittest::FOREIGN_BAZ);
    m->mutable_optional_lazy_message()->set_bb(45);
    m->add_repeated_int32(100);
    m->add_repeated_int64(101);
    m->add_repeated_uint32(102);
    m->add_repeated_uint64(103);
    m->add_repeated_sint32(104);
    m->add_repeated_sint64(105);
    m->add_repeated_fixed32(106);
    m->add_repeated_fixed64(107);
    m->add_repeated_sfixed32(108);
    m->add_repeated_sfixed64(109);
    m->add_repeated_float(110.0);
    m->add_repeated_double(111.0);
    m->add_repeated_bool(true);
    m->add_repeated_string("asdf");
    m->add_repeated_bytes("jkl;");
    m->add_repeated_nested_message()->set_bb(46);
    m->add_repeated_foreign_message()->set_c(47);
    m->add_repeated_proto2_message()->set_optional_int32(48);
    m->add_repeated_nested_enum(
        proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_BAZ);
    m->add_repeated_foreign_enum(
        proto2_nofieldpresence_unittest::FOREIGN_BAZ);
    m->add_repeated_lazy_message()->set_bb(49);
  
    m->set_oneof_uint32(1);
    m->mutable_oneof_nested_message()->set_bb(50);
    m->set_oneof_string("test");  // only this one remains set
  }
  
  void CheckNonDefaultValues(
  const proto2_nofieldpresence_unittest::TestAllTypes& m) {
    EXPECT_EQ(100, m.optional_int32());
    EXPECT_EQ(101, m.optional_int64());
    EXPECT_EQ(102, m.optional_uint32());
    EXPECT_EQ(103, m.optional_uint64());
    EXPECT_EQ(104, m.optional_sint32());
    EXPECT_EQ(105, m.optional_sint64());
    EXPECT_EQ(106, m.optional_fixed32());
    EXPECT_EQ(107, m.optional_fixed64());
    EXPECT_EQ(108, m.optional_sfixed32());
    EXPECT_EQ(109, m.optional_sfixed64());
    EXPECT_EQ(110.0, m.optional_float());
    EXPECT_EQ(111.0, m.optional_double());
    EXPECT_EQ(true, m.optional_bool());
    EXPECT_EQ("asdf", m.optional_string());
    EXPECT_EQ("jkl;", m.optional_bytes());
    EXPECT_EQ(true, m.has_optional_nested_message());
    EXPECT_EQ(42, m.optional_nested_message().bb());
    EXPECT_EQ(true, m.has_optional_foreign_message());
    EXPECT_EQ(43, m.optional_foreign_message().c());
    EXPECT_EQ(true, m.has_optional_proto2_message());
    EXPECT_EQ(44, m.optional_proto2_message().optional_int32());
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_BAZ,
              m.optional_nested_enum());
    EXPECT_EQ(proto2_nofieldpresence_unittest::FOREIGN_BAZ,
              m.optional_foreign_enum());
    EXPECT_EQ(true, m.has_optional_lazy_message());
    EXPECT_EQ(45, m.optional_lazy_message().bb());
  
    EXPECT_EQ(1, m.repeated_int32_size());
    EXPECT_EQ(100, m.repeated_int32(0));
    EXPECT_EQ(1, m.repeated_int64_size());
    EXPECT_EQ(101, m.repeated_int64(0));
    EXPECT_EQ(1, m.repeated_uint32_size());
    EXPECT_EQ(102, m.repeated_uint32(0));
    EXPECT_EQ(1, m.repeated_uint64_size());
    EXPECT_EQ(103, m.repeated_uint64(0));
    EXPECT_EQ(1, m.repeated_sint32_size());
    EXPECT_EQ(104, m.repeated_sint32(0));
    EXPECT_EQ(1, m.repeated_sint64_size());
    EXPECT_EQ(105, m.repeated_sint64(0));
    EXPECT_EQ(1, m.repeated_fixed32_size());
    EXPECT_EQ(106, m.repeated_fixed32(0));
    EXPECT_EQ(1, m.repeated_fixed64_size());
    EXPECT_EQ(107, m.repeated_fixed64(0));
    EXPECT_EQ(1, m.repeated_sfixed32_size());
    EXPECT_EQ(108, m.repeated_sfixed32(0));
    EXPECT_EQ(1, m.repeated_sfixed64_size());
    EXPECT_EQ(109, m.repeated_sfixed64(0));
    EXPECT_EQ(1, m.repeated_float_size());
    EXPECT_EQ(110.0, m.repeated_float(0));
    EXPECT_EQ(1, m.repeated_double_size());
    EXPECT_EQ(111.0, m.repeated_double(0));
    EXPECT_EQ(1, m.repeated_bool_size());
    EXPECT_EQ(true, m.repeated_bool(0));
    EXPECT_EQ(1, m.repeated_string_size());
    EXPECT_EQ("asdf", m.repeated_string(0));
    EXPECT_EQ(1, m.repeated_bytes_size());
    EXPECT_EQ("jkl;", m.repeated_bytes(0));
    EXPECT_EQ(1, m.repeated_nested_message_size());
    EXPECT_EQ(46, m.repeated_nested_message(0).bb());
    EXPECT_EQ(1, m.repeated_foreign_message_size());
    EXPECT_EQ(47, m.repeated_foreign_message(0).c());
    EXPECT_EQ(1, m.repeated_proto2_message_size());
    EXPECT_EQ(48, m.repeated_proto2_message(0).optional_int32());
    EXPECT_EQ(1, m.repeated_nested_enum_size());
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_BAZ,
              m.repeated_nested_enum(0));
    EXPECT_EQ(1, m.repeated_foreign_enum_size());
    EXPECT_EQ(proto2_nofieldpresence_unittest::FOREIGN_BAZ,
              m.repeated_foreign_enum(0));
    EXPECT_EQ(1, m.repeated_lazy_message_size());
    EXPECT_EQ(49, m.repeated_lazy_message(0).bb());
  
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes::kOneofString,
              m.oneof_field_case());
    EXPECT_EQ("test", m.oneof_string());
  }
  
  TEST(NoFieldPresenceTest, BasicMessageTest) {
    proto2_nofieldpresence_unittest::TestAllTypes message;
    // Check default values, fill all fields, check values. We just want to
    // exercise the basic getters/setter paths here to make sure no
    // field-presence-related changes broke these.
    CheckDefaultValues(message);
    FillValues(&message);
    CheckNonDefaultValues(message);
  
    // Clear() should be equivalent to getting a freshly-constructed message.
    message.Clear();
    CheckDefaultValues(message);
  }
  
  TEST(NoFieldPresenceTest, MessageFieldPresenceTest) {
    // check that presence still works properly for message fields.
    proto2_nofieldpresence_unittest::TestAllTypes message;
    EXPECT_EQ(false, message.has_optional_nested_message());
    // Getter should fetch default instance, and not cause the field to become
    // present.
    EXPECT_EQ(0, message.optional_nested_message().bb());
    EXPECT_EQ(false, message.has_optional_nested_message());
    message.mutable_optional_nested_message()->set_bb(42);
    EXPECT_EQ(true, message.has_optional_nested_message());
    message.clear_optional_nested_message();
    EXPECT_EQ(false, message.has_optional_nested_message());
  
    // Likewise for a lazy message field.
    EXPECT_EQ(false, message.has_optional_lazy_message());
    // Getter should fetch default instance, and not cause the field to become
    // present.
    EXPECT_EQ(0, message.optional_lazy_message().bb());
    EXPECT_EQ(false, message.has_optional_lazy_message());
    message.mutable_optional_lazy_message()->set_bb(42);
    EXPECT_EQ(true, message.has_optional_lazy_message());
    message.clear_optional_lazy_message();
    EXPECT_EQ(false, message.has_optional_lazy_message());
  
    // Test field presence of a message field on the default instance.
    EXPECT_EQ(false, proto2_nofieldpresence_unittest::TestAllTypes::
              default_instance().has_optional_nested_message());
  }
  
  TEST(NoFieldPresenceTest, ReflectionHasFieldTest) {
    // check that HasField reports true on all scalar fields. Check that it
    // behaves properly for message fields.
  
    proto2_nofieldpresence_unittest::TestAllTypes message;
    const Reflection* r = message.GetReflection();
    const Descriptor* desc = message.GetDescriptor();
  
    // Check initial state: scalars not present (due to need to be consistent with
    // MergeFrom()), message fields not present, oneofs not present.
    for (int i = 0; i < desc->field_count(); i++) {
      const FieldDescriptor* field = desc->field(i);
      if (field->is_repeated()) continue;
      EXPECT_EQ(false, r->HasField(message, field));
    }
  
    // Test field presence of a message field on the default instance.
    const FieldDescriptor* msg_field =
        desc->FindFieldByName("optional_nested_message");
    EXPECT_EQ(false, r->HasField(
        proto2_nofieldpresence_unittest::TestAllTypes::
        default_instance(), msg_field));
  
    // Fill all fields, expect everything to report true (check oneofs below).
    FillValues(&message);
    for (int i = 0; i < desc->field_count(); i++) {
      const FieldDescriptor* field = desc->field(i);
      if (field->is_repeated() || field->containing_oneof()) {
        continue;
      }
      if (field->options().ctype() != FieldOptions::STRING) {
        continue;
      }
      EXPECT_EQ(true, r->HasField(message, field));
    }
  
    message.Clear();
  
    // Check zero/empty-means-not-present semantics.
    const FieldDescriptor* field_int32 = desc->FindFieldByName("optional_int32");
    const FieldDescriptor* field_double =
        desc->FindFieldByName("optional_double");
    const FieldDescriptor* field_string =
        desc->FindFieldByName("optional_string");
  
    EXPECT_EQ(false, r->HasField(message, field_int32));
    EXPECT_EQ(false, r->HasField(message, field_double));
    EXPECT_EQ(false, r->HasField(message, field_string));
  
    message.set_optional_int32(42);
    EXPECT_EQ(true, r->HasField(message, field_int32));
    message.set_optional_int32(0);
    EXPECT_EQ(false, r->HasField(message, field_int32));
  
    message.set_optional_double(42.0);
    EXPECT_EQ(true, r->HasField(message, field_double));
    message.set_optional_double(0.0);
    EXPECT_EQ(false, r->HasField(message, field_double));
  
    message.set_optional_string("test");
    EXPECT_EQ(true, r->HasField(message, field_string));
    message.set_optional_string("");
    EXPECT_EQ(false, r->HasField(message, field_string));
  }
  
  TEST(NoFieldPresenceTest, ReflectionClearFieldTest) {
    proto2_nofieldpresence_unittest::TestAllTypes message;
  
    const Reflection* r = message.GetReflection();
    const Descriptor* desc = message.GetDescriptor();
  
    const FieldDescriptor* field_int32 = desc->FindFieldByName("optional_int32");
    const FieldDescriptor* field_double =
        desc->FindFieldByName("optional_double");
    const FieldDescriptor* field_string =
        desc->FindFieldByName("optional_string");
    const FieldDescriptor* field_message =
        desc->FindFieldByName("optional_nested_message");
    const FieldDescriptor* field_lazy =
        desc->FindFieldByName("optional_lazy_message");
  
    message.set_optional_int32(42);
    r->ClearField(&message, field_int32);
    EXPECT_EQ(0, message.optional_int32());
  
    message.set_optional_double(42.0);
    r->ClearField(&message, field_double);
    EXPECT_EQ(0.0, message.optional_double());
  
    message.set_optional_string("test");
    r->ClearField(&message, field_string);
    EXPECT_EQ("", message.optional_string());
  
    message.mutable_optional_nested_message()->set_bb(1234);
    r->ClearField(&message, field_message);
    EXPECT_FALSE(message.has_optional_nested_message());
    EXPECT_EQ(0, message.optional_nested_message().bb());
  
    message.mutable_optional_lazy_message()->set_bb(42);
    r->ClearField(&message, field_lazy);
    EXPECT_FALSE(message.has_optional_lazy_message());
    EXPECT_EQ(0, message.optional_lazy_message().bb());
  }
  
  TEST(NoFieldPresenceTest, HasFieldOneofsTest) {
    // check that HasField behaves properly for oneofs.
    proto2_nofieldpresence_unittest::TestAllTypes message;
  
    const Reflection* r = message.GetReflection();
    const Descriptor* desc = message.GetDescriptor();
    const FieldDescriptor* desc_oneof_uint32 =
        desc->FindFieldByName("oneof_uint32");
    const FieldDescriptor* desc_oneof_nested_message =
        desc->FindFieldByName("oneof_nested_message");
    const FieldDescriptor* desc_oneof_string =
        desc->FindFieldByName("oneof_string");
    GOOGLE_CHECK(desc_oneof_uint32 != nullptr);
    GOOGLE_CHECK(desc_oneof_nested_message != nullptr);
    GOOGLE_CHECK(desc_oneof_string != nullptr);
  
    EXPECT_EQ(false, r->HasField(message, desc_oneof_uint32));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_nested_message));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_string));
  
    message.set_oneof_string("test");
    EXPECT_EQ(false, r->HasField(message, desc_oneof_uint32));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_nested_message));
    EXPECT_EQ(true, r->HasField(message, desc_oneof_string));
    message.mutable_oneof_nested_message()->set_bb(42);
    EXPECT_EQ(false, r->HasField(message, desc_oneof_uint32));
    EXPECT_EQ(true, r->HasField(message, desc_oneof_nested_message));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_string));
  
    message.Clear();
    EXPECT_EQ(false, r->HasField(message, desc_oneof_uint32));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_nested_message));
    EXPECT_EQ(false, r->HasField(message, desc_oneof_string));
  }
  
  TEST(NoFieldPresenceTest, DontSerializeDefaultValuesTest) {
    // check that serialized data contains only non-zero numeric fields/non-empty
    // string/byte fields.
    proto2_nofieldpresence_unittest::TestAllTypes message;
    string output;
  
    // All default values -> no output.
    message.SerializeToString(&output);
    EXPECT_EQ(0, output.size());
  
    // Zero values -> still no output.
    message.set_optional_int32(0);
    message.set_optional_int64(0);
    message.set_optional_uint32(0);
    message.set_optional_uint64(0);
    message.set_optional_sint32(0);
    message.set_optional_sint64(0);
    message.set_optional_fixed32(0);
    message.set_optional_fixed64(0);
    message.set_optional_sfixed32(0);
    message.set_optional_sfixed64(0);
    message.set_optional_float(0);
    message.set_optional_double(0);
    message.set_optional_bool(0);
    message.set_optional_string("");
    message.set_optional_bytes("");
    message.set_optional_nested_enum(
        proto2_nofieldpresence_unittest::TestAllTypes_NestedEnum_FOO);  // first enum entry
    message.set_optional_foreign_enum(
        proto2_nofieldpresence_unittest::FOREIGN_FOO);  // first enum entry
  
    message.SerializeToString(&output);
    EXPECT_EQ(0, output.size());
  
    message.set_optional_int32(1);
    message.SerializeToString(&output);
    EXPECT_EQ(2, output.size());
    EXPECT_EQ("\x08\x01", output);
  
    message.set_optional_int32(0);
    message.SerializeToString(&output);
    EXPECT_EQ(0, output.size());
  }
  
  TEST(NoFieldPresenceTest, MergeFromIfNonzeroTest) {
    // check that MergeFrom copies if nonzero/nondefault only.
    proto2_nofieldpresence_unittest::TestAllTypes source;
    proto2_nofieldpresence_unittest::TestAllTypes dest;
  
    dest.set_optional_int32(42);
    dest.set_optional_string("test");
    source.set_optional_int32(0);
    source.set_optional_string("");
    // MergeFrom() copies only if present in serialization, i.e., non-zero.
    dest.MergeFrom(source);
    EXPECT_EQ(42, dest.optional_int32());
    EXPECT_EQ("test", dest.optional_string());
  
    source.set_optional_int32(84);
    source.set_optional_string("test2");
    dest.MergeFrom(source);
    EXPECT_EQ(84, dest.optional_int32());
    EXPECT_EQ("test2", dest.optional_string());
  }
  
  TEST(NoFieldPresenceTest, IsInitializedTest) {
    // Check that IsInitialized works properly.
    proto2_nofieldpresence_unittest::TestProto2Required message;
  
    EXPECT_EQ(true, message.IsInitialized());
    message.mutable_proto2()->set_a(1);
    EXPECT_EQ(false, message.IsInitialized());
    message.mutable_proto2()->set_b(1);
    EXPECT_EQ(false, message.IsInitialized());
    message.mutable_proto2()->set_c(1);
    EXPECT_EQ(true, message.IsInitialized());
  }
  
  TEST(NoFieldPresenceTest, LazyMessageFieldHasBit) {
    // Check that has-bit interaction with lazy message works (has-bit before and
    // after lazy decode).
    proto2_nofieldpresence_unittest::TestAllTypes message;
    const Reflection* r = message.GetReflection();
    const Descriptor* desc = message.GetDescriptor();
    const FieldDescriptor* field = desc->FindFieldByName("optional_lazy_message");
    GOOGLE_CHECK(field != nullptr);
  
    EXPECT_EQ(false, message.has_optional_lazy_message());
    EXPECT_EQ(false, r->HasField(message, field));
  
    message.mutable_optional_lazy_message()->set_bb(42);
    EXPECT_EQ(true, message.has_optional_lazy_message());
    EXPECT_EQ(true, r->HasField(message, field));
  
    // Serialize and parse with a new message object so that lazy field on new
    // object is in unparsed state.
    string output;
    message.SerializeToString(&output);
    proto2_nofieldpresence_unittest::TestAllTypes message2;
    message2.ParseFromString(output);
  
    EXPECT_EQ(true, message2.has_optional_lazy_message());
    EXPECT_EQ(true, r->HasField(message2, field));
  
    // Access field to force lazy parse.
    EXPECT_EQ(42, message.optional_lazy_message().bb());
    EXPECT_EQ(true, message2.has_optional_lazy_message());
    EXPECT_EQ(true, r->HasField(message2, field));
  }
  
  TEST(NoFieldPresenceTest, OneofPresence) {
    proto2_nofieldpresence_unittest::TestAllTypes message;
    // oneof fields still have field presence -- ensure that this goes on the wire
    // even though its value is the empty string.
    message.set_oneof_string("");
    string serialized;
    message.SerializeToString(&serialized);
    // Tag: 113 --> tag is (113 << 3) | 2 (length delimited) = 906
    // varint: 0x8a 0x07
    // Length: 0x00
    EXPECT_EQ(3, serialized.size());
    EXPECT_EQ(static_cast<char>(0x8a), serialized.at(0));
    EXPECT_EQ(static_cast<char>(0x07), serialized.at(1));
    EXPECT_EQ(static_cast<char>(0x00), serialized.at(2));
  
    message.Clear();
    EXPECT_TRUE(message.ParseFromString(serialized));
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes::kOneofString,
              message.oneof_field_case());
  
    // Also test int32 and enum fields.
    message.Clear();
    message.set_oneof_uint32(0);  // would not go on wire if ordinary field.
    message.SerializeToString(&serialized);
    EXPECT_EQ(3, serialized.size());
    EXPECT_TRUE(message.ParseFromString(serialized));
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes::kOneofUint32,
              message.oneof_field_case());
  
    message.Clear();
    message.set_oneof_enum(proto2_nofieldpresence_unittest::
                           TestAllTypes_NestedEnum_FOO);  // default value.
    message.SerializeToString(&serialized);
    EXPECT_EQ(3, serialized.size());
    EXPECT_TRUE(message.ParseFromString(serialized));
    EXPECT_EQ(proto2_nofieldpresence_unittest::TestAllTypes::kOneofEnum,
              message.oneof_field_case());
  
    message.Clear();
    message.set_oneof_string("test");
    message.clear_oneof_string();
    EXPECT_EQ(0, message.ByteSize());
  }
  
  }  // namespace
  }  // namespace protobuf
  }  // namespace google
  
  