modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc

/*
 *  Copyright (c) 2013 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 "modules/rtp_rtcp/source/rtp_rtcp_impl.h"

#include <map>
#include <memory>
#include <set>

#include "api/transport/field_trial_based_config.h"
#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
#include "modules/rtp_rtcp/source/rtcp_packet.h"
#include "modules/rtp_rtcp/source/rtcp_packet/nack.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/rtp_sender_video.h"
#include "rtc_base/rate_limiter.h"
#include "test/gmock.h"
#include "test/gtest.h"
#include "test/rtcp_packet_parser.h"

using ::testing::ElementsAre;
using ::testing::Eq;
using ::testing::Field;
using ::testing::Gt;
using ::testing::Not;
using ::testing::Optional;

namespace webrtc {
namespace {
const uint32_t kSenderSsrc = 0x12345;
const uint32_t kReceiverSsrc = 0x23456;
const int64_t kOneWayNetworkDelayMs = 100;
const uint8_t kBaseLayerTid = 0;
const uint8_t kHigherLayerTid = 1;
const uint16_t kSequenceNumber = 100;
const uint8_t kPayloadType = 100;
const int kWidth = 320;
const int kHeight = 100;

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"

class RtcpRttStatsTestImpl : public RtcpRttStats {
 public:
  RtcpRttStatsTestImpl() : rtt_ms_(0) {}
  ~RtcpRttStatsTestImpl() override = default;

  void OnRttUpdate(int64_t rtt_ms) override { rtt_ms_ = rtt_ms; }
  int64_t LastProcessedRtt() const override { return rtt_ms_; }
  int64_t rtt_ms_;
};

class SendTransport : public Transport {
 public:
  SendTransport()
      : receiver_(nullptr),
        clock_(nullptr),
        delay_ms_(0),
        rtp_packets_sent_(0),
        rtcp_packets_sent_(0) {}

  void SetRtpRtcpModule(ModuleRtpRtcpImpl* receiver) { receiver_ = receiver; }
  void SimulateNetworkDelay(int64_t delay_ms, SimulatedClock* clock) {
    clock_ = clock;
    delay_ms_ = delay_ms;
  }
  bool SendRtp(const uint8_t* data,
               size_t len,
               const PacketOptions& options) override {
    RtpPacket packet;
    EXPECT_TRUE(packet.Parse(data, len));
    ++rtp_packets_sent_;
    last_rtp_sequence_number_ = packet.SequenceNumber();
    return true;
  }
  bool SendRtcp(const uint8_t* data, size_t len) override {
    test::RtcpPacketParser parser;
    parser.Parse(data, len);
    last_nack_list_ = parser.nack()->packet_ids();

    if (clock_) {
      clock_->AdvanceTimeMilliseconds(delay_ms_);
    }
    EXPECT_TRUE(receiver_);
    receiver_->IncomingRtcpPacket(data, len);
    ++rtcp_packets_sent_;
    return true;
  }
  size_t NumRtcpSent() { return rtcp_packets_sent_; }
  ModuleRtpRtcpImpl* receiver_;
  SimulatedClock* clock_;
  int64_t delay_ms_;
  int rtp_packets_sent_;
  size_t rtcp_packets_sent_;
  uint16_t last_rtp_sequence_number_;
  std::vector<uint16_t> last_nack_list_;
};

class RtpRtcpModule : public RtcpPacketTypeCounterObserver {
 public:
  RtpRtcpModule(SimulatedClock* clock, bool is_sender)
      : is_sender_(is_sender),
        receive_statistics_(ReceiveStatistics::Create(clock)),
        clock_(clock) {
    CreateModuleImpl();
    transport_.SimulateNetworkDelay(kOneWayNetworkDelayMs, clock);
  }

  const bool is_sender_;
  RtcpPacketTypeCounter packets_sent_;
  RtcpPacketTypeCounter packets_received_;
  std::unique_ptr<ReceiveStatistics> receive_statistics_;
  SendTransport transport_;
  RtcpRttStatsTestImpl rtt_stats_;
  std::unique_ptr<ModuleRtpRtcpImpl> impl_;
  int rtcp_report_interval_ms_ = 0;

  void RtcpPacketTypesCounterUpdated(
      uint32_t ssrc,
      const RtcpPacketTypeCounter& packet_counter) override {
    counter_map_[ssrc] = packet_counter;
  }

  RtcpPacketTypeCounter RtcpSent() {
    // RTCP counters for remote SSRC.
    return counter_map_[is_sender_ ? kReceiverSsrc : kSenderSsrc];
  }

  RtcpPacketTypeCounter RtcpReceived() {
    // Received RTCP stats for (own) local SSRC.
    return counter_map_[impl_->SSRC()];
  }
  int RtpSent() { return transport_.rtp_packets_sent_; }
  uint16_t LastRtpSequenceNumber() {
    return transport_.last_rtp_sequence_number_;
  }
  std::vector<uint16_t> LastNackListSent() {
    return transport_.last_nack_list_;
  }
  void SetRtcpReportIntervalAndReset(int rtcp_report_interval_ms) {
    rtcp_report_interval_ms_ = rtcp_report_interval_ms;
    CreateModuleImpl();
  }

 private:
  void CreateModuleImpl() {
    RtpRtcpInterface::Configuration config;
    config.audio = false;
    config.clock = clock_;
    config.outgoing_transport = &transport_;
    config.receive_statistics = receive_statistics_.get();
    config.rtcp_packet_type_counter_observer = this;
    config.rtt_stats = &rtt_stats_;
    config.rtcp_report_interval_ms = rtcp_report_interval_ms_;
    config.local_media_ssrc = is_sender_ ? kSenderSsrc : kReceiverSsrc;
    config.need_rtp_packet_infos = true;
    config.non_sender_rtt_measurement = true;

    impl_.reset(new ModuleRtpRtcpImpl(config));
    impl_->SetRemoteSSRC(is_sender_ ? kReceiverSsrc : kSenderSsrc);
    impl_->SetRTCPStatus(RtcpMode::kCompound);
  }

  SimulatedClock* const clock_;
  std::map<uint32_t, RtcpPacketTypeCounter> counter_map_;
};
}  // namespace

class RtpRtcpImplTest : public ::testing::Test {
 protected:
  RtpRtcpImplTest()
      : clock_(133590000000000),
        sender_(&clock_, /*is_sender=*/true),
        receiver_(&clock_, /*is_sender=*/false) {}

  void SetUp() override {
    // Send module.
    EXPECT_EQ(0, sender_.impl_->SetSendingStatus(true));
    sender_.impl_->SetSendingMediaStatus(true);
    sender_.impl_->SetSequenceNumber(kSequenceNumber);
    sender_.impl_->SetStorePacketsStatus(true, 100);

    FieldTrialBasedConfig field_trials;
    RTPSenderVideo::Config video_config;
    video_config.clock = &clock_;
    video_config.rtp_sender = sender_.impl_->RtpSender();
    video_config.field_trials = &field_trials;
    sender_video_ = std::make_unique<RTPSenderVideo>(video_config);

    // Receive module.
    EXPECT_EQ(0, receiver_.impl_->SetSendingStatus(false));
    receiver_.impl_->SetSendingMediaStatus(false);
    // Transport settings.
    sender_.transport_.SetRtpRtcpModule(receiver_.impl_.get());
    receiver_.transport_.SetRtpRtcpModule(sender_.impl_.get());
  }

  SimulatedClock clock_;
  RtpRtcpModule sender_;
  std::unique_ptr<RTPSenderVideo> sender_video_;
  RtpRtcpModule receiver_;

  void SendFrame(const RtpRtcpModule* module,
                 RTPSenderVideo* sender,
                 uint8_t tid) {
    RTPVideoHeaderVP8 vp8_header = {};
    vp8_header.temporalIdx = tid;
    RTPVideoHeader rtp_video_header;
    rtp_video_header.frame_type = VideoFrameType::kVideoFrameKey;
    rtp_video_header.width = kWidth;
    rtp_video_header.height = kHeight;
    rtp_video_header.rotation = kVideoRotation_0;
    rtp_video_header.content_type = VideoContentType::UNSPECIFIED;
    rtp_video_header.playout_delay = {-1, -1};
    rtp_video_header.is_first_packet_in_frame = true;
    rtp_video_header.simulcastIdx = 0;
    rtp_video_header.codec = kVideoCodecVP8;
    rtp_video_header.video_type_header = vp8_header;
    rtp_video_header.video_timing = {0u, 0u, 0u, 0u, 0u, 0u, false};

    const uint8_t payload[100] = {0};
    EXPECT_TRUE(module->impl_->OnSendingRtpFrame(0, 0, kPayloadType, true));
    EXPECT_TRUE(sender->SendVideo(kPayloadType, VideoCodecType::kVideoCodecVP8,
                                  0, 0, payload, rtp_video_header, 0));
  }

  void IncomingRtcpNack(const RtpRtcpModule* module, uint16_t sequence_number) {
    bool sender = module->impl_->SSRC() == kSenderSsrc;
    rtcp::Nack nack;
    uint16_t list[1];
    list[0] = sequence_number;
    const uint16_t kListLength = sizeof(list) / sizeof(list[0]);
    nack.SetSenderSsrc(sender ? kReceiverSsrc : kSenderSsrc);
    nack.SetMediaSsrc(sender ? kSenderSsrc : kReceiverSsrc);
    nack.SetPacketIds(list, kListLength);
    rtc::Buffer packet = nack.Build();
    module->impl_->IncomingRtcpPacket(packet.data(), packet.size());
  }
};

TEST_F(RtpRtcpImplTest, RetransmitsAllLayers) {
  // Send frames.
  EXPECT_EQ(0, sender_.RtpSent());
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);  // kSequenceNumber
  SendFrame(&sender_, sender_video_.get(),
            kHigherLayerTid);  // kSequenceNumber + 1
  SendFrame(&sender_, sender_video_.get(),
            kNoTemporalIdx);  // kSequenceNumber + 2
  EXPECT_EQ(3, sender_.RtpSent());
  EXPECT_EQ(kSequenceNumber + 2, sender_.LastRtpSequenceNumber());

  // Min required delay until retransmit = 5 + RTT ms (RTT = 0).
  clock_.AdvanceTimeMilliseconds(5);

  // Frame with kBaseLayerTid re-sent.
  IncomingRtcpNack(&sender_, kSequenceNumber);
  EXPECT_EQ(4, sender_.RtpSent());
  EXPECT_EQ(kSequenceNumber, sender_.LastRtpSequenceNumber());
  // Frame with kHigherLayerTid re-sent.
  IncomingRtcpNack(&sender_, kSequenceNumber + 1);
  EXPECT_EQ(5, sender_.RtpSent());
  EXPECT_EQ(kSequenceNumber + 1, sender_.LastRtpSequenceNumber());
  // Frame with kNoTemporalIdx re-sent.
  IncomingRtcpNack(&sender_, kSequenceNumber + 2);
  EXPECT_EQ(6, sender_.RtpSent());
  EXPECT_EQ(kSequenceNumber + 2, sender_.LastRtpSequenceNumber());
}

TEST_F(RtpRtcpImplTest, Rtt) {
  RtpPacketReceived packet;
  packet.SetTimestamp(1);
  packet.SetSequenceNumber(123);
  packet.SetSsrc(kSenderSsrc);
  packet.AllocatePayload(100 - 12);
  receiver_.receive_statistics_->OnRtpPacket(packet);

  // Send Frame before sending an SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  // Sender module should send an SR.
  EXPECT_EQ(0, sender_.impl_->SendRTCP(kRtcpReport));

  // Receiver module should send a RR with a response to the last received SR.
  clock_.AdvanceTimeMilliseconds(1000);
  EXPECT_EQ(0, receiver_.impl_->SendRTCP(kRtcpReport));

  // Verify RTT.
  int64_t rtt;
  int64_t avg_rtt;
  int64_t min_rtt;
  int64_t max_rtt;
  EXPECT_EQ(
      0, sender_.impl_->RTT(kReceiverSsrc, &rtt, &avg_rtt, &min_rtt, &max_rtt));
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, rtt, 1);
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, avg_rtt, 1);
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, min_rtt, 1);
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, max_rtt, 1);

  // No RTT from other ssrc.
  EXPECT_EQ(-1, sender_.impl_->RTT(kReceiverSsrc + 1, &rtt, &avg_rtt, &min_rtt,
                                   &max_rtt));

  // Verify RTT from rtt_stats config.
  EXPECT_EQ(0, sender_.rtt_stats_.LastProcessedRtt());
  EXPECT_EQ(0, sender_.impl_->rtt_ms());
  sender_.impl_->Process();
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, sender_.rtt_stats_.LastProcessedRtt(),
              1);
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, sender_.impl_->rtt_ms(), 1);
}

TEST_F(RtpRtcpImplTest, RttForReceiverOnly) {
  // Receiver module should send a Receiver time reference report (RTRR).
  EXPECT_EQ(0, receiver_.impl_->SendRTCP(kRtcpReport));

  // Sender module should send a response to the last received RTRR (DLRR).
  clock_.AdvanceTimeMilliseconds(1000);
  // Send Frame before sending a SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  EXPECT_EQ(0, sender_.impl_->SendRTCP(kRtcpReport));

  // Verify RTT.
  EXPECT_EQ(0, receiver_.rtt_stats_.LastProcessedRtt());
  EXPECT_EQ(0, receiver_.impl_->rtt_ms());
  receiver_.impl_->Process();
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs,
              receiver_.rtt_stats_.LastProcessedRtt(), 1);
  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, receiver_.impl_->rtt_ms(), 1);
}

TEST_F(RtpRtcpImplTest, NoSrBeforeMedia) {
  // Ignore fake transport delays in this test.
  sender_.transport_.SimulateNetworkDelay(0, &clock_);
  receiver_.transport_.SimulateNetworkDelay(0, &clock_);

  sender_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 0u);

  // Verify no SR is sent before media has been sent, RR should still be sent
  // from the receiving module though.
  clock_.AdvanceTimeMilliseconds(2000);
  sender_.impl_->Process();
  receiver_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 0u);
  EXPECT_EQ(receiver_.transport_.NumRtcpSent(), 1u);

  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 1u);
}

TEST_F(RtpRtcpImplTest, RtcpPacketTypeCounter_Nack) {
  EXPECT_EQ(0U, sender_.RtcpReceived().nack_packets);
  EXPECT_EQ(0U, receiver_.RtcpSent().nack_packets);

  // Receive module sends a NACK.
  const uint16_t kNackLength = 1;
  uint16_t nack_list[kNackLength] = {123};
  EXPECT_EQ(0, receiver_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, receiver_.RtcpSent().nack_packets);

  // Send module receives the NACK.
  EXPECT_EQ(1U, sender_.RtcpReceived().nack_packets);
}

TEST_F(RtpRtcpImplTest, AddStreamDataCounters) {
  StreamDataCounters rtp;
  rtp.transmitted.packets = 1;
  rtp.transmitted.payload_bytes = 1;
  rtp.transmitted.header_bytes = 2;
  rtp.transmitted.padding_bytes = 3;
  EXPECT_EQ(rtp.transmitted.TotalBytes(), rtp.transmitted.payload_bytes +
                                              rtp.transmitted.header_bytes +
                                              rtp.transmitted.padding_bytes);

  StreamDataCounters rtp2;
  rtp2.transmitted.packets = 10;
  rtp2.transmitted.payload_bytes = 10;
  rtp2.retransmitted.header_bytes = 4;
  rtp2.retransmitted.payload_bytes = 5;
  rtp2.retransmitted.padding_bytes = 6;
  rtp2.retransmitted.packets = 7;
  rtp2.fec.packets = 8;

  StreamDataCounters sum = rtp;
  sum.Add(rtp2);
  EXPECT_EQ(11U, sum.transmitted.packets);
  EXPECT_EQ(11U, sum.transmitted.payload_bytes);
  EXPECT_EQ(2U, sum.transmitted.header_bytes);
  EXPECT_EQ(3U, sum.transmitted.padding_bytes);
  EXPECT_EQ(4U, sum.retransmitted.header_bytes);
  EXPECT_EQ(5U, sum.retransmitted.payload_bytes);
  EXPECT_EQ(6U, sum.retransmitted.padding_bytes);
  EXPECT_EQ(7U, sum.retransmitted.packets);
  EXPECT_EQ(8U, sum.fec.packets);
  EXPECT_EQ(sum.transmitted.TotalBytes(),
            rtp.transmitted.TotalBytes() + rtp2.transmitted.TotalBytes());
}

TEST_F(RtpRtcpImplTest, SendsInitialNackList) {
  // Send module sends a NACK.
  const uint16_t kNackLength = 1;
  uint16_t nack_list[kNackLength] = {123};
  EXPECT_EQ(0U, sender_.RtcpSent().nack_packets);
  // Send Frame before sending a compound RTCP that starts with SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(123));
}

TEST_F(RtpRtcpImplTest, SendsExtendedNackList) {
  // Send module sends a NACK.
  const uint16_t kNackLength = 1;
  uint16_t nack_list[kNackLength] = {123};
  EXPECT_EQ(0U, sender_.RtcpSent().nack_packets);
  // Send Frame before sending a compound RTCP that starts with SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(123));

  // Same list not re-send.
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(123));

  // Only extended list sent.
  const uint16_t kNackExtLength = 2;
  uint16_t nack_list_ext[kNackExtLength] = {123, 124};
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list_ext, kNackExtLength));
  EXPECT_EQ(2U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(124));
}

TEST_F(RtpRtcpImplTest, ReSendsNackListAfterRttMs) {
  sender_.transport_.SimulateNetworkDelay(0, &clock_);
  // Send module sends a NACK.
  const uint16_t kNackLength = 2;
  uint16_t nack_list[kNackLength] = {123, 125};
  EXPECT_EQ(0U, sender_.RtcpSent().nack_packets);
  // Send Frame before sending a compound RTCP that starts with SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(123, 125));

  // Same list not re-send, rtt interval has not passed.
  const int kStartupRttMs = 100;
  clock_.AdvanceTimeMilliseconds(kStartupRttMs);
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, sender_.RtcpSent().nack_packets);

  // Rtt interval passed, full list sent.
  clock_.AdvanceTimeMilliseconds(1);
  EXPECT_EQ(0, sender_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(2U, sender_.RtcpSent().nack_packets);
  EXPECT_THAT(sender_.LastNackListSent(), ElementsAre(123, 125));
}

TEST_F(RtpRtcpImplTest, UniqueNackRequests) {
  receiver_.transport_.SimulateNetworkDelay(0, &clock_);
  EXPECT_EQ(0U, receiver_.RtcpSent().nack_packets);
  EXPECT_EQ(0U, receiver_.RtcpSent().nack_requests);
  EXPECT_EQ(0U, receiver_.RtcpSent().unique_nack_requests);
  EXPECT_EQ(0, receiver_.RtcpSent().UniqueNackRequestsInPercent());

  // Receive module sends NACK request.
  const uint16_t kNackLength = 4;
  uint16_t nack_list[kNackLength] = {10, 11, 13, 18};
  EXPECT_EQ(0, receiver_.impl_->SendNACK(nack_list, kNackLength));
  EXPECT_EQ(1U, receiver_.RtcpSent().nack_packets);
  EXPECT_EQ(4U, receiver_.RtcpSent().nack_requests);
  EXPECT_EQ(4U, receiver_.RtcpSent().unique_nack_requests);
  EXPECT_THAT(receiver_.LastNackListSent(), ElementsAre(10, 11, 13, 18));

  // Send module receives the request.
  EXPECT_EQ(1U, sender_.RtcpReceived().nack_packets);
  EXPECT_EQ(4U, sender_.RtcpReceived().nack_requests);
  EXPECT_EQ(4U, sender_.RtcpReceived().unique_nack_requests);
  EXPECT_EQ(100, sender_.RtcpReceived().UniqueNackRequestsInPercent());

  // Receive module sends new request with duplicated packets.
  const int kStartupRttMs = 100;
  clock_.AdvanceTimeMilliseconds(kStartupRttMs + 1);
  const uint16_t kNackLength2 = 4;
  uint16_t nack_list2[kNackLength2] = {11, 18, 20, 21};
  EXPECT_EQ(0, receiver_.impl_->SendNACK(nack_list2, kNackLength2));
  EXPECT_EQ(2U, receiver_.RtcpSent().nack_packets);
  EXPECT_EQ(8U, receiver_.RtcpSent().nack_requests);
  EXPECT_EQ(6U, receiver_.RtcpSent().unique_nack_requests);
  EXPECT_THAT(receiver_.LastNackListSent(), ElementsAre(11, 18, 20, 21));

  // Send module receives the request.
  EXPECT_EQ(2U, sender_.RtcpReceived().nack_packets);
  EXPECT_EQ(8U, sender_.RtcpReceived().nack_requests);
  EXPECT_EQ(6U, sender_.RtcpReceived().unique_nack_requests);
  EXPECT_EQ(75, sender_.RtcpReceived().UniqueNackRequestsInPercent());
}

TEST_F(RtpRtcpImplTest, ConfigurableRtcpReportInterval) {
  const int kVideoReportInterval = 3000;

  // Recreate sender impl with new configuration, and redo setup.
  sender_.SetRtcpReportIntervalAndReset(kVideoReportInterval);
  SetUp();

  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);

  // Initial state
  sender_.impl_->Process();
  EXPECT_EQ(0u, sender_.transport_.NumRtcpSent());

  // Move ahead to the last ms before a rtcp is expected, no action.
  clock_.AdvanceTimeMilliseconds(kVideoReportInterval / 2 - 1);
  sender_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 0u);

  // Move ahead to the first rtcp. Send RTCP.
  clock_.AdvanceTimeMilliseconds(1);
  sender_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 1u);

  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);

  // Move ahead to the last possible second before second rtcp is expected.
  clock_.AdvanceTimeMilliseconds(kVideoReportInterval * 1 / 2 - 1);
  sender_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 1u);

  // Move ahead into the range of second rtcp, the second rtcp may be sent.
  clock_.AdvanceTimeMilliseconds(1);
  sender_.impl_->Process();
  EXPECT_GE(sender_.transport_.NumRtcpSent(), 1u);

  clock_.AdvanceTimeMilliseconds(kVideoReportInterval / 2);
  sender_.impl_->Process();
  EXPECT_GE(sender_.transport_.NumRtcpSent(), 1u);

  // Move out the range of second rtcp, the second rtcp must have been sent.
  clock_.AdvanceTimeMilliseconds(kVideoReportInterval / 2);
  sender_.impl_->Process();
  EXPECT_EQ(sender_.transport_.NumRtcpSent(), 2u);
}

TEST_F(RtpRtcpImplTest, StoresPacketInfoForSentPackets) {
  const uint32_t kStartTimestamp = 1u;
  SetUp();
  sender_.impl_->SetStartTimestamp(kStartTimestamp);
  sender_.impl_->SetSequenceNumber(1);

  PacedPacketInfo pacing_info;
  RtpPacketToSend packet(nullptr);
  packet.set_packet_type(RtpPacketToSend::Type::kVideo);
  packet.SetSsrc(kSenderSsrc);

  // Single-packet frame.
  packet.SetTimestamp(1);
  packet.set_first_packet_of_frame(true);
  packet.SetMarker(true);
  sender_.impl_->TrySendPacket(&packet, pacing_info);

  std::vector<RtpSequenceNumberMap::Info> seqno_info =
      sender_.impl_->GetSentRtpPacketInfos(std::vector<uint16_t>{1});

  EXPECT_THAT(seqno_info, ElementsAre(RtpSequenceNumberMap::Info(
                              /*timestamp=*/1 - kStartTimestamp,
                              /*is_first=*/1,
                              /*is_last=*/1)));

  // Three-packet frame.
  packet.SetTimestamp(2);
  packet.set_first_packet_of_frame(true);
  packet.SetMarker(false);
  sender_.impl_->TrySendPacket(&packet, pacing_info);

  packet.set_first_packet_of_frame(false);
  sender_.impl_->TrySendPacket(&packet, pacing_info);

  packet.SetMarker(true);
  sender_.impl_->TrySendPacket(&packet, pacing_info);

  seqno_info =
      sender_.impl_->GetSentRtpPacketInfos(std::vector<uint16_t>{2, 3, 4});

  EXPECT_THAT(seqno_info, ElementsAre(RtpSequenceNumberMap::Info(
                                          /*timestamp=*/2 - kStartTimestamp,
                                          /*is_first=*/1,
                                          /*is_last=*/0),
                                      RtpSequenceNumberMap::Info(
                                          /*timestamp=*/2 - kStartTimestamp,
                                          /*is_first=*/0,
                                          /*is_last=*/0),
                                      RtpSequenceNumberMap::Info(
                                          /*timestamp=*/2 - kStartTimestamp,
                                          /*is_first=*/0,
                                          /*is_last=*/1)));
}

// Checks that the remote sender stats are not available if no RTCP SR was sent.
TEST_F(RtpRtcpImplTest, SenderReportStatsNotAvailable) {
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(), Eq(absl::nullopt));
}

// Checks that the remote sender stats are available if an RTCP SR was sent.
TEST_F(RtpRtcpImplTest, SenderReportStatsAvailable) {
  // Send a frame in order to send an SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  // Send an SR.
  ASSERT_THAT(sender_.impl_->SendRTCP(kRtcpReport), Eq(0));
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(), Not(Eq(absl::nullopt)));
}

// Checks that the remote sender stats are not available if an RTCP SR with an
// unexpected SSRC is received.
TEST_F(RtpRtcpImplTest, SenderReportStatsNotUpdatedWithUnexpectedSsrc) {
  constexpr uint32_t kUnexpectedSenderSsrc = 0x87654321;
  static_assert(kUnexpectedSenderSsrc != kSenderSsrc, "");
  // Forge a sender report and pass it to the receiver as if an RTCP SR were
  // sent by an unexpected sender.
  rtcp::SenderReport sr;
  sr.SetSenderSsrc(kUnexpectedSenderSsrc);
  sr.SetNtp({/*seconds=*/1u, /*fractions=*/1u << 31});
  sr.SetPacketCount(123u);
  sr.SetOctetCount(456u);
  auto raw_packet = sr.Build();
  receiver_.impl_->IncomingRtcpPacket(raw_packet.data(), raw_packet.size());
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(), Eq(absl::nullopt));
}

// Checks the stats derived from the last received RTCP SR are set correctly.
TEST_F(RtpRtcpImplTest, SenderReportStatsCheckStatsFromLastReport) {
  using SenderReportStats = RtpRtcpInterface::SenderReportStats;
  const NtpTime ntp(/*seconds=*/1u, /*fractions=*/1u << 31);
  constexpr uint32_t kPacketCount = 123u;
  constexpr uint32_t kOctetCount = 456u;
  // Forge a sender report and pass it to the receiver as if an RTCP SR were
  // sent by the sender.
  rtcp::SenderReport sr;
  sr.SetSenderSsrc(kSenderSsrc);
  sr.SetNtp(ntp);
  sr.SetPacketCount(kPacketCount);
  sr.SetOctetCount(kOctetCount);
  auto raw_packet = sr.Build();
  receiver_.impl_->IncomingRtcpPacket(raw_packet.data(), raw_packet.size());

  EXPECT_THAT(
      receiver_.impl_->GetSenderReportStats(),
      Optional(AllOf(Field(&SenderReportStats::last_remote_timestamp, Eq(ntp)),
                     Field(&SenderReportStats::packets_sent, Eq(kPacketCount)),
                     Field(&SenderReportStats::bytes_sent, Eq(kOctetCount)))));
}

// Checks that the remote sender stats count equals the number of sent RTCP SRs.
TEST_F(RtpRtcpImplTest, SenderReportStatsCount) {
  using SenderReportStats = RtpRtcpInterface::SenderReportStats;
  // Send a frame in order to send an SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  // Send the first SR.
  ASSERT_THAT(sender_.impl_->SendRTCP(kRtcpReport), Eq(0));
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(),
              Optional(Field(&SenderReportStats::reports_count, Eq(1u))));
  // Send the second SR.
  ASSERT_THAT(sender_.impl_->SendRTCP(kRtcpReport), Eq(0));
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(),
              Optional(Field(&SenderReportStats::reports_count, Eq(2u))));
}

// Checks that the remote sender stats include a valid arrival time if an RTCP
// SR was sent.
TEST_F(RtpRtcpImplTest, SenderReportStatsArrivalTimestampSet) {
  // Send a frame in order to send an SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  // Send an SR.
  ASSERT_THAT(sender_.impl_->SendRTCP(kRtcpReport), Eq(0));
  auto stats = receiver_.impl_->GetSenderReportStats();
  ASSERT_THAT(stats, Not(Eq(absl::nullopt)));
  EXPECT_TRUE(stats->last_arrival_timestamp.Valid());
}

// Checks that the packet and byte counters from an RTCP SR are not zero once
// a frame is sent.
TEST_F(RtpRtcpImplTest, SenderReportStatsPacketByteCounters) {
  using SenderReportStats = RtpRtcpInterface::SenderReportStats;
  // Send a frame in order to send an SR.
  SendFrame(&sender_, sender_video_.get(), kBaseLayerTid);
  ASSERT_THAT(sender_.transport_.rtp_packets_sent_, Gt(0));
  // Advance time otherwise the RTCP SR report will not include any packets
  // generated by `SendFrame()`.
  clock_.AdvanceTimeMilliseconds(1);
  // Send an SR.
  ASSERT_THAT(sender_.impl_->SendRTCP(kRtcpReport), Eq(0));
  EXPECT_THAT(receiver_.impl_->GetSenderReportStats(),
              Optional(AllOf(Field(&SenderReportStats::packets_sent, Gt(0u)),
                             Field(&SenderReportStats::bytes_sent, Gt(0u)))));
}

#pragma clang diagnostic pop

}  // namespace webrtc