/*
 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */
#include "common_video/test/utilities.h"
#include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/random.h"
#include "test/gmock.h"
#include "test/gtest.h"

namespace webrtc {
namespace {

using ::testing::Each;
using ::testing::ElementsAre;
using ::testing::ElementsAreArray;
using ::testing::IsEmpty;

constexpr int8_t kPayloadType = 100;
constexpr uint32_t kSsrc = 0x12345678;
constexpr uint16_t kSeqNum = 0x1234;
constexpr uint8_t kSeqNumFirstByte = kSeqNum >> 8;
constexpr uint8_t kSeqNumSecondByte = kSeqNum & 0xff;
constexpr uint32_t kTimestamp = 0x65431278;
constexpr uint8_t kTransmissionOffsetExtensionId = 1;
constexpr uint8_t kAudioLevelExtensionId = 9;
constexpr uint8_t kRtpStreamIdExtensionId = 0xa;
constexpr uint8_t kRtpMidExtensionId = 0xb;
constexpr uint8_t kVideoTimingExtensionId = 0xc;
constexpr uint8_t kTwoByteExtensionId = 0xf0;
constexpr int32_t kTimeOffset = 0x56ce;
constexpr bool kVoiceActive = true;
constexpr uint8_t kAudioLevel = 0x5a;
constexpr char kStreamId[] = "streamid";
constexpr char kMid[] = "mid";
constexpr char kLongMid[] = "extra-long string to test two-byte header";
constexpr size_t kMaxPaddingSize = 224u;
// clang-format off
constexpr uint8_t kMinimumPacket[] = {
    0x80, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78};

constexpr uint8_t kPacketWithTO[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x01,
    0x12, 0x00, 0x56, 0xce};

constexpr uint8_t kPacketWithTOAndAL[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x02,
    0x12, 0x00, 0x56, 0xce,
    0x90, 0x80|kAudioLevel, 0x00, 0x00};

constexpr uint8_t kPacketWithTwoByteExtensionIdLast[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x10, 0x00, 0x00, 0x04,
    0x01, 0x03, 0x00, 0x56,
    0xce, 0x09, 0x01, 0x80|kAudioLevel,
    kTwoByteExtensionId, 0x03, 0x00, 0x30,  // => 0x00 0x30 0x22
    0x22, 0x00, 0x00, 0x00};                // => Playout delay.min_ms = 3*10
                                            // => Playout delay.max_ms = 34*10

constexpr uint8_t kPacketWithTwoByteExtensionIdFirst[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x10, 0x00, 0x00, 0x04,
    kTwoByteExtensionId, 0x03, 0x00, 0x30,  // => 0x00 0x30 0x22
    0x22, 0x01, 0x03, 0x00,                 // => Playout delay.min_ms = 3*10
    0x56, 0xce, 0x09, 0x01,                 // => Playout delay.max_ms = 34*10
    0x80|kAudioLevel, 0x00, 0x00, 0x00};

constexpr uint8_t kPacketWithTOAndALInvalidPadding[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x03,
    0x12, 0x00, 0x56, 0xce,
    0x00, 0x02, 0x00, 0x00,  // 0x02 is invalid padding, parsing should stop.
    0x90, 0x80|kAudioLevel, 0x00, 0x00};

constexpr uint8_t kPacketWithTOAndALReservedExtensionId[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x03,
    0x12, 0x00, 0x56, 0xce,
    0x00, 0xF0, 0x00, 0x00,  // F is a reserved id, parsing should stop.
    0x90, 0x80|kAudioLevel, 0x00, 0x00};

constexpr uint8_t kPacketWithRsid[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x03,
    0xa7, 's',  't',  'r',
    'e',  'a',  'm',  'i',
    'd' , 0x00, 0x00, 0x00};

constexpr uint8_t kPacketWithMid[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0xbe, 0xde, 0x00, 0x01,
    0xb2, 'm', 'i', 'd'};

constexpr uint32_t kCsrcs[] = {0x34567890, 0x32435465};
constexpr uint8_t kPayload[] = {'p', 'a', 'y', 'l', 'o', 'a', 'd'};
constexpr uint8_t kPacketPaddingSize = 8;
constexpr uint8_t kPacket[] = {
    0xb2, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x34, 0x56, 0x78, 0x90,
    0x32, 0x43, 0x54, 0x65,
    0xbe, 0xde, 0x00, 0x01,
    0x12, 0x00, 0x56, 0xce,
    'p', 'a', 'y', 'l', 'o', 'a', 'd',
    'p', 'a', 'd', 'd', 'i', 'n', 'g', kPacketPaddingSize};

constexpr uint8_t kPacketWithTwoByteHeaderExtension[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x10, 0x00, 0x00, 0x02,  // Two-byte header extension profile id + length.
    kTwoByteExtensionId, 0x03, 0x00, 0x56,
    0xce, 0x00, 0x00, 0x00};

constexpr uint8_t kPacketWithLongTwoByteHeaderExtension[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x10, 0x00, 0x00, 0x0B,  // Two-byte header extension profile id + length.
    kTwoByteExtensionId, 0x29, 'e', 'x',
    't', 'r', 'a', '-', 'l', 'o', 'n', 'g',
    ' ', 's', 't', 'r', 'i', 'n', 'g', ' ',
    't', 'o', ' ', 't', 'e', 's', 't', ' ',
    't', 'w', 'o', '-', 'b', 'y', 't', 'e',
    ' ', 'h', 'e', 'a', 'd', 'e', 'r', 0x00};

constexpr uint8_t kPacketWithTwoByteHeaderExtensionWithPadding[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,
    0x12, 0x34, 0x56, 0x78,
    0x10, 0x00, 0x00, 0x03,  // Two-byte header extension profile id + length.
    kTwoByteExtensionId, 0x03, 0x00, 0x56,
    0xce, 0x00, 0x00, 0x00,  // Three padding bytes.
    kAudioLevelExtensionId, 0x01, 0x80|kAudioLevel, 0x00};

constexpr uint8_t kPacketWithInvalidExtension[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,  // kTimestamp.
    0x12, 0x34, 0x56, 0x78,  // kSSrc.
    0xbe, 0xde, 0x00, 0x02,  // Extension block of size 2 x 32bit words.
    (kTransmissionOffsetExtensionId << 4) | 6,  // (6+1)-byte extension, but
           'e',  'x',  't',                     // Transmission Offset
     'd',  'a',  't',  'a',                     // expected to be 3-bytes.
     'p',  'a',  'y',  'l',  'o',  'a',  'd'};

constexpr uint8_t kPacketWithLegacyTimingExtension[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,  // kTimestamp.
    0x12, 0x34, 0x56, 0x78,  // kSSrc.
    0xbe, 0xde, 0x00, 0x04,    // Extension block of size 4 x 32bit words.
    (kVideoTimingExtensionId << 4)
      | VideoTimingExtension::kValueSizeBytes - 2,  // Old format without flags.
          0x00, 0x01, 0x00,
    0x02, 0x00, 0x03, 0x00,
    0x04, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00};
// clang-format on

void TestCreateAndParseColorSpaceExtension(bool with_hdr_metadata) {
  // Create packet with extension.
  RtpPacket::ExtensionManager extensions(/*extmap-allow-mixed=*/true);
  extensions.Register<ColorSpaceExtension>(1);
  RtpPacket packet(&extensions);
  const ColorSpace kColorSpace = CreateTestColorSpace(with_hdr_metadata);
  EXPECT_TRUE(packet.SetExtension<ColorSpaceExtension>(kColorSpace));
  packet.SetPayloadSize(42);

  // Read packet with the extension.
  RtpPacketReceived parsed(&extensions);
  EXPECT_TRUE(parsed.Parse(packet.Buffer()));
  ColorSpace parsed_color_space;
  EXPECT_TRUE(parsed.GetExtension<ColorSpaceExtension>(&parsed_color_space));
  EXPECT_EQ(kColorSpace, parsed_color_space);
}

TEST(RtpPacketTest, CreateMinimum) {
  RtpPacketToSend packet(nullptr);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  EXPECT_THAT(kMinimumPacket, ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, CreateWithExtension) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, CreateWith2Extensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel);
  EXPECT_THAT(kPacketWithTOAndAL,
              ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, CreateWithTwoByteHeaderExtensionFirst) {
  RtpPacketToSend::ExtensionManager extensions(true);
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  extensions.Register<PlayoutDelayLimits>(kTwoByteExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  // Set extension that requires two-byte header.
  PlayoutDelay playoutDelay = {30, 340};
  ASSERT_TRUE(packet.SetExtension<PlayoutDelayLimits>(playoutDelay));
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel);
  EXPECT_THAT(kPacketWithTwoByteExtensionIdFirst,
              ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, CreateWithTwoByteHeaderExtensionLast) {
  // This test will trigger RtpPacket::PromoteToTwoByteHeaderExtension().
  RtpPacketToSend::ExtensionManager extensions(true);
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  extensions.Register<PlayoutDelayLimits>(kTwoByteExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel);
  EXPECT_THAT(kPacketWithTOAndAL,
              ElementsAreArray(packet.data(), packet.size()));
  // Set extension that requires two-byte header.
  PlayoutDelay playoutDelay = {30, 340};
  ASSERT_TRUE(packet.SetExtension<PlayoutDelayLimits>(playoutDelay));
  EXPECT_THAT(kPacketWithTwoByteExtensionIdLast,
              ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, CreateWithDynamicSizedExtensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpStreamId>(kRtpStreamIdExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<RtpStreamId>(kStreamId);
  EXPECT_THAT(kPacketWithRsid, ElementsAreArray(packet.data(), packet.size()));
}

TEST(RtpPacketTest, TryToCreateWithEmptyRsid) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpStreamId>(kRtpStreamIdExtensionId);
  RtpPacketToSend packet(&extensions);
  EXPECT_FALSE(packet.SetExtension<RtpStreamId>(""));
}

TEST(RtpPacketTest, TryToCreateWithLongRsid) {
  RtpPacketToSend::ExtensionManager extensions;
  constexpr char kLongStreamId[] = "LoooooooooongRsid";
  ASSERT_EQ(strlen(kLongStreamId), 17u);
  extensions.Register<RtpStreamId>(kRtpStreamIdExtensionId);
  RtpPacketToSend packet(&extensions);
  EXPECT_FALSE(packet.SetExtension<RtpStreamId>(kLongStreamId));
}

TEST(RtpPacketTest, TryToCreateWithEmptyMid) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpMid>(kRtpMidExtensionId);
  RtpPacketToSend packet(&extensions);
  EXPECT_FALSE(packet.SetExtension<RtpMid>(""));
}

TEST(RtpPacketTest, TryToCreateWithLongMid) {
  RtpPacketToSend::ExtensionManager extensions;
  constexpr char kLongMid[] = "LoooooooooonogMid";
  ASSERT_EQ(strlen(kLongMid), 17u);
  extensions.Register<RtpMid>(kRtpMidExtensionId);
  RtpPacketToSend packet(&extensions);
  EXPECT_FALSE(packet.SetExtension<RtpMid>(kLongMid));
}

TEST(RtpPacketTest, TryToCreateTwoByteHeaderNotSupported) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<AudioLevel>(kTwoByteExtensionId);
  RtpPacketToSend packet(&extensions);
  // Set extension that requires two-byte header.
  EXPECT_FALSE(packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel));
}

TEST(RtpPacketTest, CreateWithMaxSizeHeaderExtension) {
  const std::string kValue = "123456789abcdef";
  RtpPacket::ExtensionManager extensions;
  extensions.Register<RtpMid>(1);
  extensions.Register<RtpStreamId>(2);

  RtpPacket packet(&extensions);
  EXPECT_TRUE(packet.SetExtension<RtpMid>(kValue));

  packet.SetPayloadSize(42);
  // Rewriting allocated extension is allowed.
  EXPECT_TRUE(packet.SetExtension<RtpMid>(kValue));
  // Adding another extension after payload is set is not allowed.
  EXPECT_FALSE(packet.SetExtension<RtpStreamId>(kValue));

  // Read packet with the extension.
  RtpPacketReceived parsed(&extensions);
  EXPECT_TRUE(parsed.Parse(packet.Buffer()));
  std::string read;
  EXPECT_TRUE(parsed.GetExtension<RtpMid>(&read));
  EXPECT_EQ(read, kValue);
}

TEST(RtpPacketTest, SetReservedExtensionsAfterPayload) {
  const size_t kPayloadSize = 4;
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketToSend packet(&extensions);

  EXPECT_TRUE(packet.ReserveExtension<TransmissionOffset>());
  packet.SetPayloadSize(kPayloadSize);
  // Can't set extension after payload.
  EXPECT_FALSE(packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel));
  // Unless reserved.
  EXPECT_TRUE(packet.SetExtension<TransmissionOffset>(kTimeOffset));
}

TEST(RtpPacketTest, CreatePurePadding) {
  const size_t kPaddingSize = kMaxPaddingSize - 1;
  RtpPacketToSend packet(nullptr, 12 + kPaddingSize);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);

  EXPECT_LT(packet.size(), packet.capacity());
  EXPECT_FALSE(packet.SetPadding(kPaddingSize + 1));
  EXPECT_TRUE(packet.SetPadding(kPaddingSize));
  EXPECT_EQ(packet.size(), packet.capacity());
}

TEST(RtpPacketTest, CreateUnalignedPadding) {
  const size_t kPayloadSize = 3;  // Make padding start at unaligned address.
  RtpPacketToSend packet(nullptr, 12 + kPayloadSize + kMaxPaddingSize);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetPayloadSize(kPayloadSize);

  EXPECT_LT(packet.size(), packet.capacity());
  EXPECT_TRUE(packet.SetPadding(kMaxPaddingSize));
  EXPECT_EQ(packet.size(), packet.capacity());
}

TEST(RtpPacketTest, WritesPaddingSizeToLastByte) {
  const size_t kPaddingSize = 5;
  RtpPacket packet;

  EXPECT_TRUE(packet.SetPadding(kPaddingSize));
  EXPECT_EQ(packet.data()[packet.size() - 1], kPaddingSize);
}

TEST(RtpPacketTest, UsesZerosForPadding) {
  const size_t kPaddingSize = 5;
  RtpPacket packet;

  EXPECT_TRUE(packet.SetPadding(kPaddingSize));
  EXPECT_THAT(rtc::MakeArrayView(packet.data() + 12, kPaddingSize - 1),
              Each(0));
}

TEST(RtpPacketTest, CreateOneBytePadding) {
  size_t kPayloadSize = 123;
  RtpPacket packet(nullptr, 12 + kPayloadSize + 1);
  packet.SetPayloadSize(kPayloadSize);

  EXPECT_TRUE(packet.SetPadding(1));

  EXPECT_EQ(packet.size(), 12 + kPayloadSize + 1);
  EXPECT_EQ(packet.padding_size(), 1u);
}

TEST(RtpPacketTest, FailsToAddPaddingWithoutCapacity) {
  size_t kPayloadSize = 123;
  RtpPacket packet(nullptr, 12 + kPayloadSize);
  packet.SetPayloadSize(kPayloadSize);

  EXPECT_FALSE(packet.SetPadding(1));
}

TEST(RtpPacketTest, ParseMinimum) {
  RtpPacketReceived packet;
  EXPECT_TRUE(packet.Parse(kMinimumPacket, sizeof(kMinimumPacket)));
  EXPECT_EQ(kPayloadType, packet.PayloadType());
  EXPECT_EQ(kSeqNum, packet.SequenceNumber());
  EXPECT_EQ(kTimestamp, packet.Timestamp());
  EXPECT_EQ(kSsrc, packet.Ssrc());
  EXPECT_EQ(0u, packet.padding_size());
  EXPECT_EQ(0u, packet.payload_size());
}

TEST(RtpPacketTest, ParseBuffer) {
  rtc::CopyOnWriteBuffer unparsed(kMinimumPacket);
  const uint8_t* raw = unparsed.data();

  RtpPacketReceived packet;
  EXPECT_TRUE(packet.Parse(std::move(unparsed)));
  EXPECT_EQ(raw, packet.data());  // Expect packet take the buffer without copy.
  EXPECT_EQ(kSeqNum, packet.SequenceNumber());
  EXPECT_EQ(kTimestamp, packet.Timestamp());
  EXPECT_EQ(kSsrc, packet.Ssrc());
  EXPECT_EQ(0u, packet.padding_size());
  EXPECT_EQ(0u, packet.payload_size());
}

TEST(RtpPacketTest, ParseWithExtension) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);

  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTO, sizeof(kPacketWithTO)));
  EXPECT_EQ(kPayloadType, packet.PayloadType());
  EXPECT_EQ(kSeqNum, packet.SequenceNumber());
  EXPECT_EQ(kTimestamp, packet.Timestamp());
  EXPECT_EQ(kSsrc, packet.Ssrc());
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  EXPECT_EQ(0u, packet.payload_size());
  EXPECT_EQ(0u, packet.padding_size());
}

TEST(RtpPacketTest, GetExtensionWithoutParametersReturnsOptionalValue) {
  RtpPacket::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<RtpStreamId>(kRtpStreamIdExtensionId);

  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTO, sizeof(kPacketWithTO)));

  auto time_offset = packet.GetExtension<TransmissionOffset>();
  static_assert(
      std::is_same<decltype(time_offset),
                   absl::optional<TransmissionOffset::value_type>>::value,
      "");
  EXPECT_EQ(time_offset, kTimeOffset);
  EXPECT_FALSE(packet.GetExtension<RtpStreamId>().has_value());
}

TEST(RtpPacketTest, GetRawExtensionWhenPresent) {
  constexpr uint8_t kRawPacket[] = {
      // comment for clang-format to align kRawPacket nicer.
      0x90, 100,  0x5e, 0x04,  //
      0x65, 0x43, 0x12, 0x78,  // Timestamp.
      0x12, 0x34, 0x56, 0x78,  // Ssrc
      0xbe, 0xde, 0x00, 0x01,  // Extension header
      0x12, 'm',  'i',  'd',   // 3-byte extension with id=1.
      'p',  'a',  'y',  'l',  'o', 'a', 'd'};
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpMid>(1);
  RtpPacket packet(&extensions);
  ASSERT_TRUE(packet.Parse(kRawPacket, sizeof(kRawPacket)));
  EXPECT_THAT(packet.GetRawExtension<RtpMid>(), ElementsAre('m', 'i', 'd'));
}

TEST(RtpPacketTest, GetRawExtensionWhenAbsent) {
  constexpr uint8_t kRawPacket[] = {
      // comment for clang-format to align kRawPacket nicer.
      0x90, 100,  0x5e, 0x04,  //
      0x65, 0x43, 0x12, 0x78,  // Timestamp.
      0x12, 0x34, 0x56, 0x78,  // Ssrc
      0xbe, 0xde, 0x00, 0x01,  // Extension header
      0x12, 'm',  'i',  'd',   // 3-byte extension with id=1.
      'p',  'a',  'y',  'l',  'o', 'a', 'd'};
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpMid>(2);
  RtpPacket packet(&extensions);
  ASSERT_TRUE(packet.Parse(kRawPacket, sizeof(kRawPacket)));
  EXPECT_THAT(packet.GetRawExtension<RtpMid>(), IsEmpty());
}

TEST(RtpPacketTest, ParseWithInvalidSizedExtension) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);

  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithInvalidExtension,
                           sizeof(kPacketWithInvalidExtension)));

  // Extension should be ignored.
  int32_t time_offset;
  EXPECT_FALSE(packet.GetExtension<TransmissionOffset>(&time_offset));

  // But shouldn't prevent reading payload.
  EXPECT_THAT(packet.payload(), ElementsAreArray(kPayload));
}

TEST(RtpPacketTest, ParseWithOverSizedExtension) {
  // clang-format off
  const uint8_t bad_packet[] = {
      0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
      0x65, 0x43, 0x12, 0x78,  // kTimestamp.
      0x12, 0x34, 0x56, 0x78,  // kSsrc.
      0xbe, 0xde, 0x00, 0x01,  // Extension of size 1x32bit word.
      0x00,  // Add a byte of padding.
            0x12,  // Extension id 1 size (2+1).
                  0xda, 0x1a  // Only 2 bytes of extension payload.
  };
  // clang-format on
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(1);
  RtpPacketReceived packet(&extensions);

  // Parse should ignore bad extension and proceed.
  EXPECT_TRUE(packet.Parse(bad_packet, sizeof(bad_packet)));
  int32_t time_offset;
  // But extracting extension should fail.
  EXPECT_FALSE(packet.GetExtension<TransmissionOffset>(&time_offset));
}

TEST(RtpPacketTest, ParseWith2Extensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTOAndAL, sizeof(kPacketWithTOAndAL)));
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  bool voice_active;
  uint8_t audio_level;
  EXPECT_TRUE(packet.GetExtension<AudioLevel>(&voice_active, &audio_level));
  EXPECT_EQ(kVoiceActive, voice_active);
  EXPECT_EQ(kAudioLevel, audio_level);
}

TEST(RtpPacketTest, ParseSecondPacketWithFewerExtensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTOAndAL, sizeof(kPacketWithTOAndAL)));
  EXPECT_TRUE(packet.HasExtension<TransmissionOffset>());
  EXPECT_TRUE(packet.HasExtension<AudioLevel>());

  // Second packet without audio level.
  EXPECT_TRUE(packet.Parse(kPacketWithTO, sizeof(kPacketWithTO)));
  EXPECT_TRUE(packet.HasExtension<TransmissionOffset>());
  EXPECT_FALSE(packet.HasExtension<AudioLevel>());
}

TEST(RtpPacketTest, ParseWith2ExtensionsInvalidPadding) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTOAndALInvalidPadding,
                           sizeof(kPacketWithTOAndALInvalidPadding)));
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  bool voice_active;
  uint8_t audio_level;
  EXPECT_FALSE(packet.GetExtension<AudioLevel>(&voice_active, &audio_level));
}

TEST(RtpPacketTest, ParseWith2ExtensionsReservedExtensionId) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTOAndALReservedExtensionId,
                           sizeof(kPacketWithTOAndALReservedExtensionId)));
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  bool voice_active;
  uint8_t audio_level;
  EXPECT_FALSE(packet.GetExtension<AudioLevel>(&voice_active, &audio_level));
}

TEST(RtpPacketTest, ParseWithAllFeatures) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacket, sizeof(kPacket)));
  EXPECT_EQ(kPayloadType, packet.PayloadType());
  EXPECT_EQ(kSeqNum, packet.SequenceNumber());
  EXPECT_EQ(kTimestamp, packet.Timestamp());
  EXPECT_EQ(kSsrc, packet.Ssrc());
  EXPECT_THAT(packet.Csrcs(), ElementsAreArray(kCsrcs));
  EXPECT_THAT(packet.payload(), ElementsAreArray(kPayload));
  EXPECT_EQ(kPacketPaddingSize, packet.padding_size());
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
}

TEST(RtpPacketTest, ParseTwoByteHeaderExtension) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTwoByteExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithTwoByteHeaderExtension,
                           sizeof(kPacketWithTwoByteHeaderExtension)));
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
}

TEST(RtpPacketTest, ParseLongTwoByteHeaderExtension) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<RtpMid>(kTwoByteExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithLongTwoByteHeaderExtension,
                           sizeof(kPacketWithLongTwoByteHeaderExtension)));
  std::string long_rtp_mid;
  EXPECT_TRUE(packet.GetExtension<RtpMid>(&long_rtp_mid));
  EXPECT_EQ(kLongMid, long_rtp_mid);
}

TEST(RtpPacketTest, ParseTwoByteHeaderExtensionWithPadding) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTwoByteExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(
      packet.Parse(kPacketWithTwoByteHeaderExtensionWithPadding,
                   sizeof(kPacketWithTwoByteHeaderExtensionWithPadding)));
  int32_t time_offset;
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  bool voice_active;
  uint8_t audio_level;
  EXPECT_TRUE(packet.GetExtension<AudioLevel>(&voice_active, &audio_level));
  EXPECT_EQ(kVoiceActive, voice_active);
  EXPECT_EQ(kAudioLevel, audio_level);
}

TEST(RtpPacketTest, ParseWithExtensionDelayed) {
  RtpPacketReceived packet;
  EXPECT_TRUE(packet.Parse(kPacketWithTO, sizeof(kPacketWithTO)));
  EXPECT_EQ(kPayloadType, packet.PayloadType());
  EXPECT_EQ(kSeqNum, packet.SequenceNumber());
  EXPECT_EQ(kTimestamp, packet.Timestamp());
  EXPECT_EQ(kSsrc, packet.Ssrc());

  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);

  int32_t time_offset;
  EXPECT_FALSE(packet.GetExtension<TransmissionOffset>(&time_offset));
  packet.IdentifyExtensions(extensions);
  EXPECT_TRUE(packet.GetExtension<TransmissionOffset>(&time_offset));
  EXPECT_EQ(kTimeOffset, time_offset);
  EXPECT_EQ(0u, packet.payload_size());
  EXPECT_EQ(0u, packet.padding_size());
}

TEST(RtpPacketTest, ParseDynamicSizeExtension) {
  // clang-format off
  const uint8_t kPacket1[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,  // Timestamp.
    0x12, 0x34, 0x56, 0x78,  // Ssrc.
    0xbe, 0xde, 0x00, 0x02,  // Extensions block of size 2x32bit words.
    0x21, 'H', 'D',          // Extension with id = 2, size = (1+1).
    0x12, 'r', 't', 'x',     // Extension with id = 1, size = (2+1).
    0x00};  // Extension padding.
  const uint8_t kPacket2[] = {
    0x90, kPayloadType, kSeqNumFirstByte, kSeqNumSecondByte,
    0x65, 0x43, 0x12, 0x78,  // Timestamp.
    0x12, 0x34, 0x56, 0x79,  // Ssrc.
    0xbe, 0xde, 0x00, 0x01,  // Extensions block of size 1x32bit words.
    0x11, 'H', 'D',          // Extension with id = 1, size = (1+1).
    0x00};  // Extension padding.
  // clang-format on
  RtpPacketReceived::ExtensionManager extensions;
  extensions.Register<RtpStreamId>(1);
  extensions.Register<RepairedRtpStreamId>(2);
  RtpPacketReceived packet(&extensions);
  ASSERT_TRUE(packet.Parse(kPacket1, sizeof(kPacket1)));

  std::string rsid;
  EXPECT_TRUE(packet.GetExtension<RtpStreamId>(&rsid));
  EXPECT_EQ(rsid, "rtx");

  std::string repaired_rsid;
  EXPECT_TRUE(packet.GetExtension<RepairedRtpStreamId>(&repaired_rsid));
  EXPECT_EQ(repaired_rsid, "HD");

  // Parse another packet with RtpStreamId extension of different size.
  ASSERT_TRUE(packet.Parse(kPacket2, sizeof(kPacket2)));
  EXPECT_TRUE(packet.GetExtension<RtpStreamId>(&rsid));
  EXPECT_EQ(rsid, "HD");
  EXPECT_FALSE(packet.GetExtension<RepairedRtpStreamId>(&repaired_rsid));
}

TEST(RtpPacketTest, ParseWithMid) {
  RtpPacketReceived::ExtensionManager extensions;
  extensions.Register<RtpMid>(kRtpMidExtensionId);
  RtpPacketReceived packet(&extensions);
  ASSERT_TRUE(packet.Parse(kPacketWithMid, sizeof(kPacketWithMid)));

  std::string mid;
  EXPECT_TRUE(packet.GetExtension<RtpMid>(&mid));
  EXPECT_EQ(mid, kMid);
}

struct UncopyableValue {
  UncopyableValue() = default;
  UncopyableValue(const UncopyableValue&) = delete;
  UncopyableValue& operator=(const UncopyableValue&) = delete;
};
struct UncopyableExtension {
  static constexpr RTPExtensionType kId = kRtpExtensionGenericFrameDescriptor02;
  static constexpr char kUri[] = "uri";

  static size_t ValueSize(const UncopyableValue& value) { return 1; }
  static bool Write(rtc::ArrayView<uint8_t> data,
                    const UncopyableValue& value) {
    return true;
  }
  static bool Parse(rtc::ArrayView<const uint8_t> data,
                    UncopyableValue* value) {
    return true;
  }
};
constexpr RTPExtensionType UncopyableExtension::kId;
constexpr char UncopyableExtension::kUri[];

TEST(RtpPacketTest, SetUncopyableExtension) {
  RtpPacket::ExtensionManager extensions;
  extensions.Register<UncopyableExtension>(1);
  RtpPacket rtp_packet(&extensions);

  UncopyableValue value;
  EXPECT_TRUE(rtp_packet.SetExtension<UncopyableExtension>(value));
}

TEST(RtpPacketTest, GetUncopyableExtension) {
  RtpPacket::ExtensionManager extensions;
  extensions.Register<UncopyableExtension>(1);
  RtpPacket rtp_packet(&extensions);
  UncopyableValue value;
  rtp_packet.SetExtension<UncopyableExtension>(value);

  UncopyableValue value2;
  EXPECT_TRUE(rtp_packet.GetExtension<UncopyableExtension>(&value2));
}

TEST(RtpPacketTest, CreateAndParseTimingFrameExtension) {
  // Create a packet with video frame timing extension populated.
  RtpPacketToSend::ExtensionManager send_extensions;
  send_extensions.Register<VideoTimingExtension>(kVideoTimingExtensionId);
  RtpPacketToSend send_packet(&send_extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  VideoSendTiming timing;
  timing.encode_start_delta_ms = 1;
  timing.encode_finish_delta_ms = 2;
  timing.packetization_finish_delta_ms = 3;
  timing.pacer_exit_delta_ms = 4;
  timing.flags =
      VideoSendTiming::kTriggeredByTimer | VideoSendTiming::kTriggeredBySize;

  send_packet.SetExtension<VideoTimingExtension>(timing);

  // Serialize the packet and then parse it again.
  RtpPacketReceived::ExtensionManager extensions;
  extensions.Register<VideoTimingExtension>(kVideoTimingExtensionId);
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  VideoSendTiming receivied_timing;
  EXPECT_TRUE(
      receive_packet.GetExtension<VideoTimingExtension>(&receivied_timing));

  // Only check first and last timestamp (covered by other tests) plus flags.
  EXPECT_EQ(receivied_timing.encode_start_delta_ms,
            timing.encode_start_delta_ms);
  EXPECT_EQ(receivied_timing.pacer_exit_delta_ms, timing.pacer_exit_delta_ms);
  EXPECT_EQ(receivied_timing.flags, timing.flags);
}

TEST(RtpPacketTest, ParseLegacyTimingFrameExtension) {
  // Parse the modified packet.
  RtpPacketReceived::ExtensionManager extensions;
  extensions.Register<VideoTimingExtension>(kVideoTimingExtensionId);
  RtpPacketReceived packet(&extensions);
  EXPECT_TRUE(packet.Parse(kPacketWithLegacyTimingExtension,
                           sizeof(kPacketWithLegacyTimingExtension)));
  VideoSendTiming receivied_timing;
  EXPECT_TRUE(packet.GetExtension<VideoTimingExtension>(&receivied_timing));

  // Check first and last timestamp are still OK. Flags should now be 0.
  EXPECT_EQ(receivied_timing.encode_start_delta_ms, 1);
  EXPECT_EQ(receivied_timing.pacer_exit_delta_ms, 4);
  EXPECT_EQ(receivied_timing.flags, 0);
}

TEST(RtpPacketTest, CreateAndParseColorSpaceExtension) {
  TestCreateAndParseColorSpaceExtension(/*with_hdr_metadata=*/true);
}

TEST(RtpPacketTest, CreateAndParseColorSpaceExtensionWithoutHdrMetadata) {
  TestCreateAndParseColorSpaceExtension(/*with_hdr_metadata=*/false);
}

TEST(RtpPacketTest, CreateAndParseAbsoluteCaptureTime) {
  // Create a packet with absolute capture time extension populated.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<AbsoluteCaptureTimeExtension>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr AbsoluteCaptureTime kAbsoluteCaptureTime{
      /*absolute_capture_timestamp=*/9876543210123456789ULL,
      /*estimated_capture_clock_offset=*/-1234567890987654321LL};
  send_packet.SetExtension<AbsoluteCaptureTimeExtension>(kAbsoluteCaptureTime);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  AbsoluteCaptureTime received_absolute_capture_time;
  EXPECT_TRUE(receive_packet.GetExtension<AbsoluteCaptureTimeExtension>(
      &received_absolute_capture_time));
  EXPECT_EQ(kAbsoluteCaptureTime.absolute_capture_timestamp,
            received_absolute_capture_time.absolute_capture_timestamp);
  EXPECT_EQ(kAbsoluteCaptureTime.estimated_capture_clock_offset,
            received_absolute_capture_time.estimated_capture_clock_offset);
}

TEST(RtpPacketTest,
     CreateAndParseAbsoluteCaptureTimeWithoutEstimatedCaptureClockOffset) {
  // Create a packet with absolute capture time extension populated.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<AbsoluteCaptureTimeExtension>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr AbsoluteCaptureTime kAbsoluteCaptureTime{
      /*absolute_capture_timestamp=*/9876543210123456789ULL,
      /*estimated_capture_clock_offset=*/absl::nullopt};
  send_packet.SetExtension<AbsoluteCaptureTimeExtension>(kAbsoluteCaptureTime);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  AbsoluteCaptureTime received_absolute_capture_time;
  EXPECT_TRUE(receive_packet.GetExtension<AbsoluteCaptureTimeExtension>(
      &received_absolute_capture_time));
  EXPECT_EQ(kAbsoluteCaptureTime.absolute_capture_timestamp,
            received_absolute_capture_time.absolute_capture_timestamp);
  EXPECT_EQ(kAbsoluteCaptureTime.estimated_capture_clock_offset,
            received_absolute_capture_time.estimated_capture_clock_offset);
}

TEST(RtpPacketTest, CreateAndParseTransportSequenceNumber) {
  // Create a packet with transport sequence number extension populated.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<TransportSequenceNumber>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr int kTransportSequenceNumber = 12345;
  send_packet.SetExtension<TransportSequenceNumber>(kTransportSequenceNumber);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  uint16_t received_transport_sequeunce_number;
  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumber>(
      &received_transport_sequeunce_number));
  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
}

TEST(RtpPacketTest, CreateAndParseTransportSequenceNumberV2) {
  // Create a packet with transport sequence number V2 extension populated.
  // No feedback request means that the extension will be two bytes unless it's
  // pre-allocated.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<TransportSequenceNumberV2>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr int kTransportSequenceNumber = 12345;
  send_packet.SetExtension<TransportSequenceNumberV2>(kTransportSequenceNumber,
                                                      absl::nullopt);
  EXPECT_EQ(send_packet.GetRawExtension<TransportSequenceNumberV2>().size(),
            2u);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  uint16_t received_transport_sequeunce_number;
  absl::optional<FeedbackRequest> received_feedback_request;
  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumberV2>(
      &received_transport_sequeunce_number, &received_feedback_request));
  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
  EXPECT_FALSE(received_feedback_request);
}

TEST(RtpPacketTest, CreateAndParseTransportSequenceNumberV2Preallocated) {
  // Create a packet with transport sequence number V2 extension populated.
  // No feedback request means that the extension could be two bytes, but since
  // it's pre-allocated we don't know if it is with or without feedback request
  // therefore the size is four bytes.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<TransportSequenceNumberV2>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr int kTransportSequenceNumber = 12345;
  constexpr absl::optional<FeedbackRequest> kNoFeedbackRequest =
      FeedbackRequest{/*include_timestamps=*/false, /*sequence_count=*/0};
  send_packet.ReserveExtension<TransportSequenceNumberV2>();
  send_packet.SetExtension<TransportSequenceNumberV2>(kTransportSequenceNumber,
                                                      kNoFeedbackRequest);
  EXPECT_EQ(send_packet.GetRawExtension<TransportSequenceNumberV2>().size(),
            4u);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  uint16_t received_transport_sequeunce_number;
  absl::optional<FeedbackRequest> received_feedback_request;
  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumberV2>(
      &received_transport_sequeunce_number, &received_feedback_request));
  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
  EXPECT_FALSE(received_feedback_request);
}

TEST(RtpPacketTest,
     CreateAndParseTransportSequenceNumberV2WithFeedbackRequest) {
  // Create a packet with TransportSequenceNumberV2 extension populated.
  RtpPacketToSend::ExtensionManager extensions;
  constexpr int kExtensionId = 1;
  extensions.Register<TransportSequenceNumberV2>(kExtensionId);
  RtpPacketToSend send_packet(&extensions);
  send_packet.SetPayloadType(kPayloadType);
  send_packet.SetSequenceNumber(kSeqNum);
  send_packet.SetTimestamp(kTimestamp);
  send_packet.SetSsrc(kSsrc);

  constexpr int kTransportSequenceNumber = 12345;
  constexpr absl::optional<FeedbackRequest> kFeedbackRequest =
      FeedbackRequest{/*include_timestamps=*/true, /*sequence_count=*/3};
  send_packet.SetExtension<TransportSequenceNumberV2>(kTransportSequenceNumber,
                                                      kFeedbackRequest);

  // Serialize the packet and then parse it again.
  RtpPacketReceived receive_packet(&extensions);
  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));

  // Parse transport sequence number and feedback request.
  uint16_t received_transport_sequeunce_number;
  absl::optional<FeedbackRequest> received_feedback_request;
  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumberV2>(
      &received_transport_sequeunce_number, &received_feedback_request));
  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
  ASSERT_TRUE(received_feedback_request);
  EXPECT_EQ(received_feedback_request->include_timestamps,
            kFeedbackRequest->include_timestamps);
  EXPECT_EQ(received_feedback_request->sequence_count,
            kFeedbackRequest->sequence_count);
}

TEST(RtpPacketTest, ReservedExtensionsCountedAsSetExtension) {
  // Register two extensions.
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);

  RtpPacketReceived packet(&extensions);

  // Reserve slot for only one of them.
  EXPECT_TRUE(packet.ReserveExtension<TransmissionOffset>());
  // Non-registered extension cannot be reserved.
  EXPECT_FALSE(packet.ReserveExtension<VideoContentTypeExtension>());

  // Only the extension that is both registered and reserved matches
  // IsExtensionReserved().
  EXPECT_FALSE(packet.HasExtension<VideoContentTypeExtension>());
  EXPECT_FALSE(packet.HasExtension<AudioLevel>());
  EXPECT_TRUE(packet.HasExtension<TransmissionOffset>());
}

// Tests that RtpPacket::RemoveExtension can successfully remove extensions.
TEST(RtpPacketTest, RemoveMultipleExtensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel);

  EXPECT_THAT(kPacketWithTOAndAL,
              ElementsAreArray(packet.data(), packet.size()));

  // Remove one of two extensions.
  EXPECT_TRUE(packet.RemoveExtension(kRtpExtensionAudioLevel));

  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));

  // Remove remaining extension.
  EXPECT_TRUE(packet.RemoveExtension(kRtpExtensionTransmissionTimeOffset));

  EXPECT_THAT(kMinimumPacket, ElementsAreArray(packet.data(), packet.size()));
}

// Tests that RtpPacket::RemoveExtension can successfully remove extension when
// other extensions are present but not registered.
TEST(RtpPacketTest, RemoveExtensionPreservesOtherUnregisteredExtensions) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);
  packet.SetExtension<AudioLevel>(kVoiceActive, kAudioLevel);

  EXPECT_THAT(kPacketWithTOAndAL,
              ElementsAreArray(packet.data(), packet.size()));

  // "Unregister" kRtpExtensionTransmissionTimeOffset.
  RtpPacketToSend::ExtensionManager extensions1;
  extensions1.Register<AudioLevel>(kAudioLevelExtensionId);
  packet.IdentifyExtensions(extensions1);

  // Make sure we can not delete extension which is set but not registered.
  EXPECT_FALSE(packet.RemoveExtension(kRtpExtensionTransmissionTimeOffset));

  // Remove registered extension.
  EXPECT_TRUE(packet.RemoveExtension(kRtpExtensionAudioLevel));

  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));
}

// Tests that RtpPacket::RemoveExtension fails if extension is not present or
// not registered and does not modify packet.
TEST(RtpPacketTest, RemoveExtensionFailure) {
  RtpPacketToSend::ExtensionManager extensions;
  extensions.Register<TransmissionOffset>(kTransmissionOffsetExtensionId);
  extensions.Register<AudioLevel>(kAudioLevelExtensionId);
  RtpPacketToSend packet(&extensions);
  packet.SetPayloadType(kPayloadType);
  packet.SetSequenceNumber(kSeqNum);
  packet.SetTimestamp(kTimestamp);
  packet.SetSsrc(kSsrc);
  packet.SetExtension<TransmissionOffset>(kTimeOffset);

  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));

  // Try to remove extension, which was registered, but not set.
  EXPECT_FALSE(packet.RemoveExtension(kRtpExtensionAudioLevel));

  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));

  // Try to remove extension, which was not registered.
  EXPECT_FALSE(packet.RemoveExtension(kRtpExtensionPlayoutDelay));

  EXPECT_THAT(kPacketWithTO, ElementsAreArray(packet.data(), packet.size()));
}

}  // namespace
}  // namespace webrtc