webrtc/modules/pacing/packet_router_unittest.cc - src - Git at Google

 /*
  *  Copyright (c) 2015 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 <list>
 #include <memory>

 #include "webrtc/modules/pacing/packet_router.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/mocks/mock_rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/fakeclock.h"
 #include "webrtc/test/gmock.h"
 #include "webrtc/test/gtest.h"

 using ::testing::_;
 using ::testing::AnyNumber;
 using ::testing::Field;
 using ::testing::NiceMock;
 using ::testing::Return;

 namespace webrtc {

 class PacketRouterTest : public ::testing::Test {
  public:
   PacketRouterTest() : packet_router_(new PacketRouter()) {}
  protected:
   static const int kProbeMinProbes = 5;
   static const int kProbeMinBytes = 1000;
   const std::unique_ptr<PacketRouter> packet_router_;
 };

 TEST_F(PacketRouterTest, TimeToSendPacket) {
   MockRtpRtcp rtp_1;
   MockRtpRtcp rtp_2;
   packet_router_->AddSendRtpModule(&rtp_1);
   packet_router_->AddSendRtpModule(&rtp_2);

   const uint16_t kSsrc1 = 1234;
   uint16_t sequence_number = 17;
   uint64_t timestamp = 7890;
   bool retransmission = false;

   // Send on the first module by letting rtp_1 be sending with correct ssrc.
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, SSRC()).Times(1).WillOnce(Return(kSsrc1));
   EXPECT_CALL(rtp_1, TimeToSendPacket(
                          kSsrc1, sequence_number, timestamp, retransmission,
                          Field(&PacedPacketInfo::probe_cluster_id, 1)))
       .Times(1)
       .WillOnce(Return(true));
   EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc1, sequence_number, timestamp, retransmission,
       PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

   // Send on the second module by letting rtp_2 be sending, but not rtp_1.
   ++sequence_number;
   timestamp += 30;
   retransmission = true;
   const uint16_t kSsrc2 = 4567;
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
   EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_CALL(rtp_2, TimeToSendPacket(
                          kSsrc2, sequence_number, timestamp, retransmission,
                          Field(&PacedPacketInfo::probe_cluster_id, 2)))
       .Times(1)
       .WillOnce(Return(true));
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc2, sequence_number, timestamp, retransmission,
       PacedPacketInfo(2, kProbeMinProbes, kProbeMinBytes)));

   // No module is sending, hence no packet should be sent.
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc1, sequence_number, timestamp, retransmission,
       PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

   // Add a packet with incorrect ssrc and test it's dropped in the router.
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, SSRC()).Times(1).WillOnce(Return(kSsrc1));
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
   EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc1 + kSsrc2, sequence_number, timestamp, retransmission,
       PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

   packet_router_->RemoveSendRtpModule(&rtp_1);

   // rtp_1 has been removed, try sending a packet on that ssrc and make sure
   // it is dropped as expected by not expecting any calls to rtp_1.
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
   EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc1, sequence_number, timestamp, retransmission,
       PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
                       kProbeMinBytes)));

   packet_router_->RemoveSendRtpModule(&rtp_2);
 }

 TEST_F(PacketRouterTest, TimeToSendPadding) {
   const uint16_t kSsrc1 = 1234;
   const uint16_t kSsrc2 = 4567;

   MockRtpRtcp rtp_1;
   EXPECT_CALL(rtp_1, RtxSendStatus()).WillOnce(Return(kRtxOff));
   EXPECT_CALL(rtp_1, SSRC()).WillRepeatedly(Return(kSsrc1));
   MockRtpRtcp rtp_2;
   // rtp_2 will be prioritized for padding.
   EXPECT_CALL(rtp_2, RtxSendStatus()).WillOnce(Return(kRtxRedundantPayloads));
   EXPECT_CALL(rtp_2, SSRC()).WillRepeatedly(Return(kSsrc2));
   packet_router_->AddSendRtpModule(&rtp_1);
   packet_router_->AddSendRtpModule(&rtp_2);

   // Default configuration, sending padding on all modules sending media,
   // ordered by priority (based on rtx mode).
   const size_t requested_padding_bytes = 1000;
   const size_t sent_padding_bytes = 890;
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2,
               TimeToSendPadding(requested_padding_bytes,
                                 Field(&PacedPacketInfo::probe_cluster_id, 111)))
       .Times(1)
       .WillOnce(Return(sent_padding_bytes));
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1,
               TimeToSendPadding(requested_padding_bytes - sent_padding_bytes,
                                 Field(&PacedPacketInfo::probe_cluster_id, 111)))
       .Times(1)
       .WillOnce(Return(requested_padding_bytes - sent_padding_bytes));
   EXPECT_EQ(requested_padding_bytes,
             packet_router_->TimeToSendPadding(
                 requested_padding_bytes,
                 PacedPacketInfo(111, kProbeMinBytes, kProbeMinBytes)));

   // Let only the lower priority module be sending and verify the padding
   // request is routed there.
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, TimeToSendPadding(_, _))
       .Times(1)
       .WillOnce(Return(sent_padding_bytes));
   EXPECT_EQ(sent_padding_bytes,
             packet_router_->TimeToSendPadding(
                 requested_padding_bytes,
                 PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
                                 kProbeMinBytes)));

   // No sending module at all.
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_1, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_2, TimeToSendPadding(_, _)).Times(0);
   EXPECT_EQ(0u,
             packet_router_->TimeToSendPadding(
                 requested_padding_bytes,
                 PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
                                 kProbeMinBytes)));

   // Only one module has BWE extensions.
   EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(false));
   EXPECT_CALL(rtp_1, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _))
       .Times(1)
       .WillOnce(Return(sent_padding_bytes));
   EXPECT_EQ(sent_padding_bytes,
             packet_router_->TimeToSendPadding(
                 requested_padding_bytes,
                 PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
                                 kProbeMinBytes)));

   packet_router_->RemoveSendRtpModule(&rtp_1);

   // rtp_1 has been removed, try sending padding and make sure rtp_1 isn't asked
   // to send by not expecting any calls. Instead verify rtp_2 is called.
   EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
   EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _)).Times(1);
   EXPECT_EQ(0u,
             packet_router_->TimeToSendPadding(
                 requested_padding_bytes,
                 PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
                                 kProbeMinBytes)));

   packet_router_->RemoveSendRtpModule(&rtp_2);
 }

 TEST_F(PacketRouterTest, SenderOnlyFunctionsRespectSendingMedia) {
   MockRtpRtcp rtp;
   packet_router_->AddSendRtpModule(&rtp);
   static const uint16_t kSsrc = 1234;
   EXPECT_CALL(rtp, SSRC()).WillRepeatedly(Return(kSsrc));
   EXPECT_CALL(rtp, SendingMedia()).WillRepeatedly(Return(false));

   // Verify that TimeToSendPacket does not end up in a receiver.
   EXPECT_CALL(rtp, TimeToSendPacket(_, _, _, _, _)).Times(0);
   EXPECT_TRUE(packet_router_->TimeToSendPacket(
       kSsrc, 1, 1, false, PacedPacketInfo(PacedPacketInfo::kNotAProbe,
                                           kProbeMinBytes, kProbeMinBytes)));
   // Verify that TimeToSendPadding does not end up in a receiver.
   EXPECT_CALL(rtp, TimeToSendPadding(_, _)).Times(0);
   EXPECT_EQ(0u,
             packet_router_->TimeToSendPadding(
                 200, PacedPacketInfo(PacedPacketInfo::kNotAProbe,
                                      kProbeMinBytes, kProbeMinBytes)));

   packet_router_->RemoveSendRtpModule(&rtp);
 }

 TEST_F(PacketRouterTest, AllocateSequenceNumbers) {
   const uint16_t kStartSeq = 0xFFF0;
   const size_t kNumPackets = 32;

   packet_router_->SetTransportWideSequenceNumber(kStartSeq - 1);

   for (size_t i = 0; i < kNumPackets; ++i) {
     uint16_t seq = packet_router_->AllocateSequenceNumber();
     uint32_t expected_unwrapped_seq = static_cast<uint32_t>(kStartSeq) + i;
     EXPECT_EQ(static_cast<uint16_t>(expected_unwrapped_seq & 0xFFFF), seq);
   }
 }

 TEST_F(PacketRouterTest, SendTransportFeedback) {
   MockRtpRtcp rtp_1;
   MockRtpRtcp rtp_2;
   packet_router_->AddSendRtpModule(&rtp_1);
   packet_router_->AddReceiveRtpModule(&rtp_2);

   rtcp::TransportFeedback feedback;
   EXPECT_CALL(rtp_1, SendFeedbackPacket(_)).Times(1).WillOnce(Return(true));
   packet_router_->SendTransportFeedback(&feedback);
   packet_router_->RemoveSendRtpModule(&rtp_1);
   EXPECT_CALL(rtp_2, SendFeedbackPacket(_)).Times(1).WillOnce(Return(true));
   packet_router_->SendTransportFeedback(&feedback);
   packet_router_->RemoveReceiveRtpModule(&rtp_2);
 }

 TEST(PacketRouterRembTest, PreferSendModuleOverReceiveModule) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp_recv;
   MockRtpRtcp rtp_send;
   PacketRouter packet_router;

   EXPECT_CALL(rtp_recv, SetREMBStatus(true)).Times(1);
   packet_router.AddReceiveRtpModule(&rtp_recv);

   const uint32_t bitrate_estimate = 456;
   const std::vector<uint32_t> ssrcs = {1234};

   ON_CALL(rtp_recv, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   EXPECT_CALL(rtp_recv, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Add a send module, which should be preferred over the receive module.
   EXPECT_CALL(rtp_recv, SetREMBStatus(false)).Times(1);
   EXPECT_CALL(rtp_send, SetREMBStatus(true)).Times(1);
   packet_router.AddSendRtpModule(&rtp_send);
   ON_CALL(rtp_recv, REMB()).WillByDefault(Return(false));
   ON_CALL(rtp_send, REMB()).WillByDefault(Return(true));

   // Lower bitrate to send another REMB packet.
   EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate - 100, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate - 100);

   EXPECT_CALL(rtp_send, SetREMBStatus(false)).Times(1);
   EXPECT_CALL(rtp_recv, SetREMBStatus(true)).Times(1);
   packet_router.RemoveSendRtpModule(&rtp_send);
   EXPECT_CALL(rtp_recv, SetREMBStatus(false)).Times(1);
   packet_router.RemoveReceiveRtpModule(&rtp_recv);
 }

 TEST(PacketRouterRembTest, LowerEstimateToSendRemb) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp;
   PacketRouter packet_router;

   EXPECT_CALL(rtp, SetREMBStatus(true)).Times(1);
   packet_router.AddSendRtpModule(&rtp);

   uint32_t bitrate_estimate = 456;
   const std::vector<uint32_t> ssrcs = {1234};

   ON_CALL(rtp, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Lower the estimate with more than 3% to trigger a call to SetREMBData right
   // away.
   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   EXPECT_CALL(rtp, SetREMBStatus(false)).Times(1);
   packet_router.RemoveSendRtpModule(&rtp);
 }

 TEST(PacketRouterRembTest, VerifyIncreasingAndDecreasing) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp;
   PacketRouter packet_router;
   packet_router.AddSendRtpModule(&rtp);

   uint32_t bitrate_estimate[] = {456, 789};
   std::vector<uint32_t> ssrcs = {1234, 5678};

   ON_CALL(rtp, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[0]);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate[0], ssrcs)).Times(1);
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[0]);

   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[1] + 100);

   // Lower the estimate to trigger a callback.
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate[1], ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[1]);

   packet_router.RemoveSendRtpModule(&rtp);
 }

 TEST(PacketRouterRembTest, NoRembForIncreasedBitrate) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp;
   PacketRouter packet_router;
   packet_router.AddSendRtpModule(&rtp);

   uint32_t bitrate_estimate = 456;
   std::vector<uint32_t> ssrcs = {1234, 5678};

   ON_CALL(rtp, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Increased estimate shouldn't trigger a callback right away.
   EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate + 1);

   // Decreasing the estimate less than 3% shouldn't trigger a new callback.
   EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
   int lower_estimate = bitrate_estimate * 98 / 100;
   packet_router.OnReceiveBitrateChanged(ssrcs, lower_estimate);

   packet_router.RemoveSendRtpModule(&rtp);
 }

 TEST(PacketRouterRembTest, ChangeSendRtpModule) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp_send;
   MockRtpRtcp rtp_recv;
   PacketRouter packet_router;
   packet_router.AddSendRtpModule(&rtp_send);
   packet_router.AddReceiveRtpModule(&rtp_recv);

   uint32_t bitrate_estimate = 456;
   std::vector<uint32_t> ssrcs = {1234, 5678};

   ON_CALL(rtp_send, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Decrease estimate to trigger a REMB.
   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Remove the sending module -> should get remb on the second module.
   packet_router.RemoveSendRtpModule(&rtp_send);

   ON_CALL(rtp_send, REMB()).WillByDefault(Return(false));
   ON_CALL(rtp_recv, REMB()).WillByDefault(Return(true));

   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp_recv, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   packet_router.RemoveReceiveRtpModule(&rtp_recv);
 }

 TEST(PacketRouterRembTest, OnlyOneRembForRepeatedOnReceiveBitrateChanged) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp;
   PacketRouter packet_router;
   packet_router.AddSendRtpModule(&rtp);

   uint32_t bitrate_estimate = 456;
   const std::vector<uint32_t> ssrcs = {1234};

   ON_CALL(rtp, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   EXPECT_CALL(rtp, SetREMBData(_, _)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Lower the estimate, should trigger a call to SetREMBData right away.
   bitrate_estimate = bitrate_estimate - 100;
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged again, this should not trigger a new callback.
   EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);
   packet_router.RemoveSendRtpModule(&rtp);
 }

 // Only register receiving modules and make sure we fallback to trigger a REMB
 // packet on this one.
 TEST(PacketRouterRembTest, NoSendingRtpModule) {
   rtc::ScopedFakeClock clock;
   MockRtpRtcp rtp;
   PacketRouter packet_router;

   EXPECT_CALL(rtp, SetREMBStatus(true)).Times(1);
   packet_router.AddReceiveRtpModule(&rtp);

   uint32_t bitrate_estimate = 456;
   const std::vector<uint32_t> ssrcs = {1234};

   ON_CALL(rtp, REMB()).WillByDefault(Return(true));
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Call OnReceiveBitrateChanged twice to get a first estimate.
   clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

   // Lower the estimate to trigger a new packet REMB packet.
   EXPECT_CALL(rtp, SetREMBData(bitrate_estimate - 100, ssrcs)).Times(1);
   packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate - 100);

   EXPECT_CALL(rtp, SetREMBStatus(false)).Times(1);
   packet_router.RemoveReceiveRtpModule(&rtp);
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2015 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 <list>
	#include <memory>

	#include "webrtc/modules/pacing/packet_router.h"
	#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
	#include "webrtc/modules/rtp_rtcp/mocks/mock_rtp_rtcp.h"
	#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
	#include "webrtc/rtc_base/checks.h"
	#include "webrtc/rtc_base/fakeclock.h"
	#include "webrtc/test/gmock.h"
	#include "webrtc/test/gtest.h"

	using ::testing::_;
	using ::testing::AnyNumber;
	using ::testing::Field;
	using ::testing::NiceMock;
	using ::testing::Return;

	namespace webrtc {

	class PacketRouterTest : public ::testing::Test {
	public:
	PacketRouterTest() : packet_router_(new PacketRouter()) {}
	protected:
	static const int kProbeMinProbes = 5;
	static const int kProbeMinBytes = 1000;
	const std::unique_ptr<PacketRouter> packet_router_;
	};

	TEST_F(PacketRouterTest, TimeToSendPacket) {
	MockRtpRtcp rtp_1;
	MockRtpRtcp rtp_2;
	packet_router_->AddSendRtpModule(&rtp_1);
	packet_router_->AddSendRtpModule(&rtp_2);

	const uint16_t kSsrc1 = 1234;
	uint16_t sequence_number = 17;
	uint64_t timestamp = 7890;
	bool retransmission = false;

	// Send on the first module by letting rtp_1 be sending with correct ssrc.
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, SSRC()).Times(1).WillOnce(Return(kSsrc1));
	EXPECT_CALL(rtp_1, TimeToSendPacket(
	kSsrc1, sequence_number, timestamp, retransmission,
	Field(&PacedPacketInfo::probe_cluster_id, 1)))
	.Times(1)
	.WillOnce(Return(true));
	EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc1, sequence_number, timestamp, retransmission,
	PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

	// Send on the second module by letting rtp_2 be sending, but not rtp_1.
	++sequence_number;
	timestamp += 30;
	retransmission = true;
	const uint16_t kSsrc2 = 4567;
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
	EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_CALL(rtp_2, TimeToSendPacket(
	kSsrc2, sequence_number, timestamp, retransmission,
	Field(&PacedPacketInfo::probe_cluster_id, 2)))
	.Times(1)
	.WillOnce(Return(true));
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc2, sequence_number, timestamp, retransmission,
	PacedPacketInfo(2, kProbeMinProbes, kProbeMinBytes)));

	// No module is sending, hence no packet should be sent.
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc1, sequence_number, timestamp, retransmission,
	PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

	// Add a packet with incorrect ssrc and test it's dropped in the router.
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, SSRC()).Times(1).WillOnce(Return(kSsrc1));
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
	EXPECT_CALL(rtp_1, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc1 + kSsrc2, sequence_number, timestamp, retransmission,
	PacedPacketInfo(1, kProbeMinProbes, kProbeMinBytes)));

	packet_router_->RemoveSendRtpModule(&rtp_1);

	// rtp_1 has been removed, try sending a packet on that ssrc and make sure
	// it is dropped as expected by not expecting any calls to rtp_1.
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, SSRC()).Times(1).WillOnce(Return(kSsrc2));
	EXPECT_CALL(rtp_2, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc1, sequence_number, timestamp, retransmission,
	PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
	kProbeMinBytes)));

	packet_router_->RemoveSendRtpModule(&rtp_2);
	}

	TEST_F(PacketRouterTest, TimeToSendPadding) {
	const uint16_t kSsrc1 = 1234;
	const uint16_t kSsrc2 = 4567;

	MockRtpRtcp rtp_1;
	EXPECT_CALL(rtp_1, RtxSendStatus()).WillOnce(Return(kRtxOff));
	EXPECT_CALL(rtp_1, SSRC()).WillRepeatedly(Return(kSsrc1));
	MockRtpRtcp rtp_2;
	// rtp_2 will be prioritized for padding.
	EXPECT_CALL(rtp_2, RtxSendStatus()).WillOnce(Return(kRtxRedundantPayloads));
	EXPECT_CALL(rtp_2, SSRC()).WillRepeatedly(Return(kSsrc2));
	packet_router_->AddSendRtpModule(&rtp_1);
	packet_router_->AddSendRtpModule(&rtp_2);

	// Default configuration, sending padding on all modules sending media,
	// ordered by priority (based on rtx mode).
	const size_t requested_padding_bytes = 1000;
	const size_t sent_padding_bytes = 890;
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2,
	TimeToSendPadding(requested_padding_bytes,
	Field(&PacedPacketInfo::probe_cluster_id, 111)))
	.Times(1)
	.WillOnce(Return(sent_padding_bytes));
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1,
	TimeToSendPadding(requested_padding_bytes - sent_padding_bytes,
	Field(&PacedPacketInfo::probe_cluster_id, 111)))
	.Times(1)
	.WillOnce(Return(requested_padding_bytes - sent_padding_bytes));
	EXPECT_EQ(requested_padding_bytes,
	packet_router_->TimeToSendPadding(
	requested_padding_bytes,
	PacedPacketInfo(111, kProbeMinBytes, kProbeMinBytes)));

	// Let only the lower priority module be sending and verify the padding
	// request is routed there.
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, TimeToSendPadding(_, _))
	.Times(1)
	.WillOnce(Return(sent_padding_bytes));
	EXPECT_EQ(sent_padding_bytes,
	packet_router_->TimeToSendPadding(
	requested_padding_bytes,
	PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
	kProbeMinBytes)));

	// No sending module at all.
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_1, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_2, TimeToSendPadding(_, _)).Times(0);
	EXPECT_EQ(0u,
	packet_router_->TimeToSendPadding(
	requested_padding_bytes,
	PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
	kProbeMinBytes)));

	// Only one module has BWE extensions.
	EXPECT_CALL(rtp_1, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_1, HasBweExtensions()).Times(1).WillOnce(Return(false));
	EXPECT_CALL(rtp_1, TimeToSendPadding(requested_padding_bytes, _)).Times(0);
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _))
	.Times(1)
	.WillOnce(Return(sent_padding_bytes));
	EXPECT_EQ(sent_padding_bytes,
	packet_router_->TimeToSendPadding(
	requested_padding_bytes,
	PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
	kProbeMinBytes)));

	packet_router_->RemoveSendRtpModule(&rtp_1);

	// rtp_1 has been removed, try sending padding and make sure rtp_1 isn't asked
	// to send by not expecting any calls. Instead verify rtp_2 is called.
	EXPECT_CALL(rtp_2, SendingMedia()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, HasBweExtensions()).Times(1).WillOnce(Return(true));
	EXPECT_CALL(rtp_2, TimeToSendPadding(requested_padding_bytes, _)).Times(1);
	EXPECT_EQ(0u,
	packet_router_->TimeToSendPadding(
	requested_padding_bytes,
	PacedPacketInfo(PacedPacketInfo::kNotAProbe, kProbeMinBytes,
	kProbeMinBytes)));

	packet_router_->RemoveSendRtpModule(&rtp_2);
	}

	TEST_F(PacketRouterTest, SenderOnlyFunctionsRespectSendingMedia) {
	MockRtpRtcp rtp;
	packet_router_->AddSendRtpModule(&rtp);
	static const uint16_t kSsrc = 1234;
	EXPECT_CALL(rtp, SSRC()).WillRepeatedly(Return(kSsrc));
	EXPECT_CALL(rtp, SendingMedia()).WillRepeatedly(Return(false));

	// Verify that TimeToSendPacket does not end up in a receiver.
	EXPECT_CALL(rtp, TimeToSendPacket(_, _, _, _, _)).Times(0);
	EXPECT_TRUE(packet_router_->TimeToSendPacket(
	kSsrc, 1, 1, false, PacedPacketInfo(PacedPacketInfo::kNotAProbe,
	kProbeMinBytes, kProbeMinBytes)));
	// Verify that TimeToSendPadding does not end up in a receiver.
	EXPECT_CALL(rtp, TimeToSendPadding(_, _)).Times(0);
	EXPECT_EQ(0u,
	packet_router_->TimeToSendPadding(
	200, PacedPacketInfo(PacedPacketInfo::kNotAProbe,
	kProbeMinBytes, kProbeMinBytes)));

	packet_router_->RemoveSendRtpModule(&rtp);
	}

	TEST_F(PacketRouterTest, AllocateSequenceNumbers) {
	const uint16_t kStartSeq = 0xFFF0;
	const size_t kNumPackets = 32;

	packet_router_->SetTransportWideSequenceNumber(kStartSeq - 1);

	for (size_t i = 0; i < kNumPackets; ++i) {
	uint16_t seq = packet_router_->AllocateSequenceNumber();
	uint32_t expected_unwrapped_seq = static_cast<uint32_t>(kStartSeq) + i;
	EXPECT_EQ(static_cast<uint16_t>(expected_unwrapped_seq & 0xFFFF), seq);
	}
	}

	TEST_F(PacketRouterTest, SendTransportFeedback) {
	MockRtpRtcp rtp_1;
	MockRtpRtcp rtp_2;
	packet_router_->AddSendRtpModule(&rtp_1);
	packet_router_->AddReceiveRtpModule(&rtp_2);

	rtcp::TransportFeedback feedback;
	EXPECT_CALL(rtp_1, SendFeedbackPacket(_)).Times(1).WillOnce(Return(true));
	packet_router_->SendTransportFeedback(&feedback);
	packet_router_->RemoveSendRtpModule(&rtp_1);
	EXPECT_CALL(rtp_2, SendFeedbackPacket(_)).Times(1).WillOnce(Return(true));
	packet_router_->SendTransportFeedback(&feedback);
	packet_router_->RemoveReceiveRtpModule(&rtp_2);
	}

	TEST(PacketRouterRembTest, PreferSendModuleOverReceiveModule) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp_recv;
	MockRtpRtcp rtp_send;
	PacketRouter packet_router;

	EXPECT_CALL(rtp_recv, SetREMBStatus(true)).Times(1);
	packet_router.AddReceiveRtpModule(&rtp_recv);

	const uint32_t bitrate_estimate = 456;
	const std::vector<uint32_t> ssrcs = {1234};

	ON_CALL(rtp_recv, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	EXPECT_CALL(rtp_recv, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Add a send module, which should be preferred over the receive module.
	EXPECT_CALL(rtp_recv, SetREMBStatus(false)).Times(1);
	EXPECT_CALL(rtp_send, SetREMBStatus(true)).Times(1);
	packet_router.AddSendRtpModule(&rtp_send);
	ON_CALL(rtp_recv, REMB()).WillByDefault(Return(false));
	ON_CALL(rtp_send, REMB()).WillByDefault(Return(true));

	// Lower bitrate to send another REMB packet.
	EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate - 100, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate - 100);

	EXPECT_CALL(rtp_send, SetREMBStatus(false)).Times(1);
	EXPECT_CALL(rtp_recv, SetREMBStatus(true)).Times(1);
	packet_router.RemoveSendRtpModule(&rtp_send);
	EXPECT_CALL(rtp_recv, SetREMBStatus(false)).Times(1);
	packet_router.RemoveReceiveRtpModule(&rtp_recv);
	}

	TEST(PacketRouterRembTest, LowerEstimateToSendRemb) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp;
	PacketRouter packet_router;

	EXPECT_CALL(rtp, SetREMBStatus(true)).Times(1);
	packet_router.AddSendRtpModule(&rtp);

	uint32_t bitrate_estimate = 456;
	const std::vector<uint32_t> ssrcs = {1234};

	ON_CALL(rtp, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Lower the estimate with more than 3% to trigger a call to SetREMBData right
	// away.
	bitrate_estimate = bitrate_estimate - 100;
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	EXPECT_CALL(rtp, SetREMBStatus(false)).Times(1);
	packet_router.RemoveSendRtpModule(&rtp);
	}

	TEST(PacketRouterRembTest, VerifyIncreasingAndDecreasing) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp;
	PacketRouter packet_router;
	packet_router.AddSendRtpModule(&rtp);

	uint32_t bitrate_estimate[] = {456, 789};
	std::vector<uint32_t> ssrcs = {1234, 5678};

	ON_CALL(rtp, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[0]);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate[0], ssrcs)).Times(1);
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[0]);

	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[1] + 100);

	// Lower the estimate to trigger a callback.
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate[1], ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate[1]);

	packet_router.RemoveSendRtpModule(&rtp);
	}

	TEST(PacketRouterRembTest, NoRembForIncreasedBitrate) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp;
	PacketRouter packet_router;
	packet_router.AddSendRtpModule(&rtp);

	uint32_t bitrate_estimate = 456;
	std::vector<uint32_t> ssrcs = {1234, 5678};

	ON_CALL(rtp, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Increased estimate shouldn't trigger a callback right away.
	EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate + 1);

	// Decreasing the estimate less than 3% shouldn't trigger a new callback.
	EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
	int lower_estimate = bitrate_estimate * 98 / 100;
	packet_router.OnReceiveBitrateChanged(ssrcs, lower_estimate);

	packet_router.RemoveSendRtpModule(&rtp);
	}

	TEST(PacketRouterRembTest, ChangeSendRtpModule) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp_send;
	MockRtpRtcp rtp_recv;
	PacketRouter packet_router;
	packet_router.AddSendRtpModule(&rtp_send);
	packet_router.AddReceiveRtpModule(&rtp_recv);

	uint32_t bitrate_estimate = 456;
	std::vector<uint32_t> ssrcs = {1234, 5678};

	ON_CALL(rtp_send, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Decrease estimate to trigger a REMB.
	bitrate_estimate = bitrate_estimate - 100;
	EXPECT_CALL(rtp_send, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Remove the sending module -> should get remb on the second module.
	packet_router.RemoveSendRtpModule(&rtp_send);

	ON_CALL(rtp_send, REMB()).WillByDefault(Return(false));
	ON_CALL(rtp_recv, REMB()).WillByDefault(Return(true));

	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	bitrate_estimate = bitrate_estimate - 100;
	EXPECT_CALL(rtp_recv, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	packet_router.RemoveReceiveRtpModule(&rtp_recv);
	}

	TEST(PacketRouterRembTest, OnlyOneRembForRepeatedOnReceiveBitrateChanged) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp;
	PacketRouter packet_router;
	packet_router.AddSendRtpModule(&rtp);

	uint32_t bitrate_estimate = 456;
	const std::vector<uint32_t> ssrcs = {1234};

	ON_CALL(rtp, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	EXPECT_CALL(rtp, SetREMBData(_, _)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Lower the estimate, should trigger a call to SetREMBData right away.
	bitrate_estimate = bitrate_estimate - 100;
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged again, this should not trigger a new callback.
	EXPECT_CALL(rtp, SetREMBData(_, _)).Times(0);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);
	packet_router.RemoveSendRtpModule(&rtp);
	}

	// Only register receiving modules and make sure we fallback to trigger a REMB
	// packet on this one.
	TEST(PacketRouterRembTest, NoSendingRtpModule) {
	rtc::ScopedFakeClock clock;
	MockRtpRtcp rtp;
	PacketRouter packet_router;

	EXPECT_CALL(rtp, SetREMBStatus(true)).Times(1);
	packet_router.AddReceiveRtpModule(&rtp);

	uint32_t bitrate_estimate = 456;
	const std::vector<uint32_t> ssrcs = {1234};

	ON_CALL(rtp, REMB()).WillByDefault(Return(true));
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Call OnReceiveBitrateChanged twice to get a first estimate.
	clock.AdvanceTime(rtc::TimeDelta::FromMilliseconds(1000));
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate);

	// Lower the estimate to trigger a new packet REMB packet.
	EXPECT_CALL(rtp, SetREMBData(bitrate_estimate - 100, ssrcs)).Times(1);
	packet_router.OnReceiveBitrateChanged(ssrcs, bitrate_estimate - 100);

	EXPECT_CALL(rtp, SetREMBStatus(false)).Times(1);
	packet_router.RemoveReceiveRtpModule(&rtp);
	}

	} // namespace webrtc