modules/congestion_controller/goog_cc/probe_controller_unittest.cc - src - Git at Google

 /*
  *  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 "modules/congestion_controller/goog_cc/probe_controller.h"

 #include <memory>

 #include "api/transport/field_trial_based_config.h"
 #include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/timestamp.h"
 #include "logging/rtc_event_log/mock/mock_rtc_event_log.h"
 #include "rtc_base/logging.h"
 #include "system_wrappers/include/clock.h"
 #include "test/field_trial.h"
 #include "test/gmock.h"
 #include "test/gtest.h"

 using ::testing::_;
 using ::testing::AtLeast;
 using ::testing::Field;
 using ::testing::Matcher;
 using ::testing::NiceMock;
 using ::testing::Return;

 namespace webrtc {
 namespace test {

 namespace {

 constexpr int kMinBitrateBps = 100;
 constexpr int kStartBitrateBps = 300;
 constexpr int kMaxBitrateBps = 10000;

 constexpr int kExponentialProbingTimeoutMs = 5000;

 constexpr int kAlrProbeInterval = 5000;
 constexpr int kAlrEndedTimeoutMs = 3000;
 constexpr int kBitrateDropTimeoutMs = 5000;
 }  // namespace

 class ProbeControllerTest : public ::testing::Test {
  protected:
   ProbeControllerTest() : clock_(100000000L) {
     probe_controller_.reset(
         new ProbeController(&field_trial_config_, &mock_rtc_event_log));
   }
   ~ProbeControllerTest() override {}

   std::vector<ProbeClusterConfig> SetNetworkAvailable(bool available) {
     NetworkAvailability msg;
     msg.at_time = Timestamp::Millis(NowMs());
     msg.network_available = available;
     return probe_controller_->OnNetworkAvailability(msg);
   }

   int64_t NowMs() { return clock_.TimeInMilliseconds(); }

   FieldTrialBasedConfig field_trial_config_;
   SimulatedClock clock_;
   NiceMock<MockRtcEventLog> mock_rtc_event_log;
   std::unique_ptr<ProbeController> probe_controller_;
 };

 TEST_F(ProbeControllerTest, InitiatesProbingAtStart) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_GE(probes.size(), 2u);
 }

 TEST_F(ProbeControllerTest, ProbeOnlyWhenNetworkIsUp) {
   SetNetworkAvailable(false);
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 0u);
   probes = SetNetworkAvailable(true);
   EXPECT_GE(probes.size(), 2u);
 }

 TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncrease) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   // Long enough to time out exponential probing.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                           kMaxBitrateBps + 100, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
 }

 TEST_F(ProbeControllerTest, ProbesOnMaxBitrateIncreaseOnlyWhenInAlr) {
   probe_controller_.reset(
       new ProbeController(&field_trial_config_, &mock_rtc_event_log));
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps - 1, NowMs());

   // Wait long enough to time out exponential probing.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 0u);

   // Probe when in alr.
   probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
   probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 1,
                                                          NowMs());
   EXPECT_EQ(probes.size(), 2u);

   // Do not probe when not in alr.
   probe_controller_->SetAlrStartTimeMs(absl::nullopt);
   probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 2,
                                                          NowMs());
   EXPECT_TRUE(probes.empty());
 }

 TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncreaseAtMaxBitrate) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   // Long enough to time out exponential probing.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps, NowMs());
   probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                           kMaxBitrateBps + 100, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
 }

 TEST_F(ProbeControllerTest, TestExponentialProbing) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());

   // Repeated probe should only be sent when estimated bitrate climbs above
   // 0.7 * 6 * kStartBitrateBps = 1260.
   probes = probe_controller_->SetEstimatedBitrate(1000, NowMs());
   EXPECT_EQ(probes.size(), 0u);

   probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * 1800);
 }

 TEST_F(ProbeControllerTest, TestExponentialProbingTimeout) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   // Advance far enough to cause a time out in waiting for probing result.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probes = probe_controller_->Process(NowMs());

   probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
   EXPECT_EQ(probes.size(), 0u);
 }

 TEST_F(ProbeControllerTest, RequestProbeInAlr) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_GE(probes.size(), 2u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
   clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
   probes = probe_controller_->RequestProbe(NowMs());

   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
 }

 TEST_F(ProbeControllerTest, RequestProbeWhenAlrEndedRecently) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 2u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   probe_controller_->SetAlrStartTimeMs(absl::nullopt);
   clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
   probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
   clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs - 1);
   probes = probe_controller_->RequestProbe(NowMs());

   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
 }

 TEST_F(ProbeControllerTest, RequestProbeWhenAlrNotEndedRecently) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 2u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   probe_controller_->SetAlrStartTimeMs(absl::nullopt);
   clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
   probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
   clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs + 1);
   probes = probe_controller_->RequestProbe(NowMs());
   EXPECT_EQ(probes.size(), 0u);
 }

 TEST_F(ProbeControllerTest, RequestProbeWhenBweDropNotRecent) {
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 2u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
   clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
   clock_.AdvanceTimeMilliseconds(kBitrateDropTimeoutMs + 1);
   probes = probe_controller_->RequestProbe(NowMs());
   EXPECT_EQ(probes.size(), 0u);
 }

 TEST_F(ProbeControllerTest, PeriodicProbing) {
   probe_controller_->EnablePeriodicAlrProbing(true);
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 2u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   int64_t start_time = clock_.TimeInMilliseconds();

   // Expect the controller to send a new probe after 5s has passed.
   probe_controller_->SetAlrStartTimeMs(start_time);
   clock_.AdvanceTimeMilliseconds(5000);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 1000);

   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

   // The following probe should be sent at 10s into ALR.
   probe_controller_->SetAlrStartTimeMs(start_time);
   clock_.AdvanceTimeMilliseconds(4000);
   probes = probe_controller_->Process(NowMs());
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
   EXPECT_EQ(probes.size(), 0u);

   probe_controller_->SetAlrStartTimeMs(start_time);
   clock_.AdvanceTimeMilliseconds(1000);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 1u);
   probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
   EXPECT_EQ(probes.size(), 0u);
 }

 TEST_F(ProbeControllerTest, PeriodicProbingAfterReset) {
   probe_controller_.reset(
       new ProbeController(&field_trial_config_, &mock_rtc_event_log));
   int64_t alr_start_time = clock_.TimeInMilliseconds();

   probe_controller_->SetAlrStartTimeMs(alr_start_time);
   probe_controller_->EnablePeriodicAlrProbing(true);
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                kMaxBitrateBps, NowMs());
   probe_controller_->Reset(NowMs());

   clock_.AdvanceTimeMilliseconds(10000);
   probes = probe_controller_->Process(NowMs());
   // Since bitrates are not yet set, no probe is sent event though we are in ALR
   // mode.
   EXPECT_EQ(probes.size(), 0u);

   probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                           kMaxBitrateBps, NowMs());
   EXPECT_EQ(probes.size(), 2u);

   // Make sure we use `kStartBitrateBps` as the estimated bitrate
   // until SetEstimatedBitrate is called with an updated estimate.
   clock_.AdvanceTimeMilliseconds(10000);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), kStartBitrateBps * 2);
 }

 TEST_F(ProbeControllerTest, TestExponentialProbingOverflow) {
   const int64_t kMbpsMultiplier = 1000000;
   auto probes = probe_controller_->SetBitrates(
       kMinBitrateBps, 10 * kMbpsMultiplier, 100 * kMbpsMultiplier, NowMs());
   // Verify that probe bitrate is capped at the specified max bitrate.
   probes =
       probe_controller_->SetEstimatedBitrate(60 * kMbpsMultiplier, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 100 * kMbpsMultiplier);
   // Verify that repeated probes aren't sent.
   probes =
       probe_controller_->SetEstimatedBitrate(100 * kMbpsMultiplier, NowMs());
   EXPECT_EQ(probes.size(), 0u);
 }

 TEST_F(ProbeControllerTest, TestAllocatedBitrateCap) {
   const int64_t kMbpsMultiplier = 1000000;
   const int64_t kMaxBitrateBps = 100 * kMbpsMultiplier;
   auto probes = probe_controller_->SetBitrates(
       kMinBitrateBps, 10 * kMbpsMultiplier, kMaxBitrateBps, NowMs());

   // Configure ALR for periodic probing.
   probe_controller_->EnablePeriodicAlrProbing(true);
   int64_t alr_start_time = clock_.TimeInMilliseconds();
   probe_controller_->SetAlrStartTimeMs(alr_start_time);

   int64_t estimated_bitrate_bps = kMaxBitrateBps / 10;
   probes =
       probe_controller_->SetEstimatedBitrate(estimated_bitrate_bps, NowMs());

   // Set a max allocated bitrate below the current estimate.
   int64_t max_allocated_bps = estimated_bitrate_bps - 1 * kMbpsMultiplier;
   probes =
       probe_controller_->OnMaxTotalAllocatedBitrate(max_allocated_bps, NowMs());
   EXPECT_TRUE(probes.empty());  // No probe since lower than current max.

   // Probes such as ALR capped at 2x the max allocation limit.
   clock_.AdvanceTimeMilliseconds(5000);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * max_allocated_bps);

   // Remove allocation limit.
   EXPECT_TRUE(
       probe_controller_->OnMaxTotalAllocatedBitrate(0, NowMs()).empty());
   clock_.AdvanceTimeMilliseconds(5000);
   probes = probe_controller_->Process(NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), estimated_bitrate_bps * 2);
 }

 TEST_F(ProbeControllerTest, ConfigurableProbingFieldTrial) {
   test::ScopedFieldTrials trials(
       "WebRTC-Bwe-ProbingConfiguration/"
       "p1:2,p2:5,step_size:3,further_probe_threshold:0.8,"
       "alloc_p1:2,alloc_p2/");
   probe_controller_.reset(
       new ProbeController(&field_trial_config_, &mock_rtc_event_log));
   auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                                5000000, NowMs());
   EXPECT_EQ(probes.size(), 2u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 600);
   EXPECT_EQ(probes[1].target_data_rate.bps(), 1500);

   // Repeated probe should only be sent when estimated bitrate climbs above
   // 0.8 * 5 * kStartBitrateBps = 1200.
   probes = probe_controller_->SetEstimatedBitrate(1100, NowMs());
   EXPECT_EQ(probes.size(), 0u);

   probes = probe_controller_->SetEstimatedBitrate(1250, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 3 * 1250);

   clock_.AdvanceTimeMilliseconds(5000);
   probes = probe_controller_->Process(NowMs());

   probe_controller_->SetAlrStartTimeMs(NowMs());
   probes = probe_controller_->OnMaxTotalAllocatedBitrate(200000, NowMs());
   EXPECT_EQ(probes.size(), 1u);
   EXPECT_EQ(probes[0].target_data_rate.bps(), 400000);
 }

 }  // namespace test
 }  // namespace webrtc
	/*
	* 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 "modules/congestion_controller/goog_cc/probe_controller.h"

	#include <memory>

	#include "api/transport/field_trial_based_config.h"
	#include "api/transport/network_types.h"
	#include "api/units/data_rate.h"
	#include "api/units/timestamp.h"
	#include "logging/rtc_event_log/mock/mock_rtc_event_log.h"
	#include "rtc_base/logging.h"
	#include "system_wrappers/include/clock.h"
	#include "test/field_trial.h"
	#include "test/gmock.h"
	#include "test/gtest.h"

	using ::testing::_;
	using ::testing::AtLeast;
	using ::testing::Field;
	using ::testing::Matcher;
	using ::testing::NiceMock;
	using ::testing::Return;

	namespace webrtc {
	namespace test {

	namespace {

	constexpr int kMinBitrateBps = 100;
	constexpr int kStartBitrateBps = 300;
	constexpr int kMaxBitrateBps = 10000;

	constexpr int kExponentialProbingTimeoutMs = 5000;

	constexpr int kAlrProbeInterval = 5000;
	constexpr int kAlrEndedTimeoutMs = 3000;
	constexpr int kBitrateDropTimeoutMs = 5000;
	} // namespace

	class ProbeControllerTest : public ::testing::Test {
	protected:
	ProbeControllerTest() : clock_(100000000L) {
	probe_controller_.reset(
	new ProbeController(&field_trial_config_, &mock_rtc_event_log));
	}
	~ProbeControllerTest() override {}

	std::vector<ProbeClusterConfig> SetNetworkAvailable(bool available) {
	NetworkAvailability msg;
	msg.at_time = Timestamp::Millis(NowMs());
	msg.network_available = available;
	return probe_controller_->OnNetworkAvailability(msg);
	}

	int64_t NowMs() { return clock_.TimeInMilliseconds(); }

	FieldTrialBasedConfig field_trial_config_;
	SimulatedClock clock_;
	NiceMock<MockRtcEventLog> mock_rtc_event_log;
	std::unique_ptr<ProbeController> probe_controller_;
	};

	TEST_F(ProbeControllerTest, InitiatesProbingAtStart) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_GE(probes.size(), 2u);
	}

	TEST_F(ProbeControllerTest, ProbeOnlyWhenNetworkIsUp) {
	SetNetworkAvailable(false);
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 0u);
	probes = SetNetworkAvailable(true);
	EXPECT_GE(probes.size(), 2u);
	}

	TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncrease) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	// Long enough to time out exponential probing.
	clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
	probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps + 100, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
	}

	TEST_F(ProbeControllerTest, ProbesOnMaxBitrateIncreaseOnlyWhenInAlr) {
	probe_controller_.reset(
	new ProbeController(&field_trial_config_, &mock_rtc_event_log));
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps - 1, NowMs());

	// Wait long enough to time out exponential probing.
	clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 0u);

	// Probe when in alr.
	probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
	probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 1,
	NowMs());
	EXPECT_EQ(probes.size(), 2u);

	// Do not probe when not in alr.
	probe_controller_->SetAlrStartTimeMs(absl::nullopt);
	probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 2,
	NowMs());
	EXPECT_TRUE(probes.empty());
	}

	TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncreaseAtMaxBitrate) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	// Long enough to time out exponential probing.
	clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
	probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps, NowMs());
	probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps + 100, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
	}

	TEST_F(ProbeControllerTest, TestExponentialProbing) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());

	// Repeated probe should only be sent when estimated bitrate climbs above
	// 0.7 * 6 * kStartBitrateBps = 1260.
	probes = probe_controller_->SetEstimatedBitrate(1000, NowMs());
	EXPECT_EQ(probes.size(), 0u);

	probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * 1800);
	}

	TEST_F(ProbeControllerTest, TestExponentialProbingTimeout) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	// Advance far enough to cause a time out in waiting for probing result.
	clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
	probes = probe_controller_->Process(NowMs());

	probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
	EXPECT_EQ(probes.size(), 0u);
	}

	TEST_F(ProbeControllerTest, RequestProbeInAlr) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_GE(probes.size(), 2u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
	clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
	probes = probe_controller_->RequestProbe(NowMs());

	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
	}

	TEST_F(ProbeControllerTest, RequestProbeWhenAlrEndedRecently) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 2u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	probe_controller_->SetAlrStartTimeMs(absl::nullopt);
	clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
	probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
	clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs - 1);
	probes = probe_controller_->RequestProbe(NowMs());

	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
	}

	TEST_F(ProbeControllerTest, RequestProbeWhenAlrNotEndedRecently) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 2u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	probe_controller_->SetAlrStartTimeMs(absl::nullopt);
	clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
	probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
	clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs + 1);
	probes = probe_controller_->RequestProbe(NowMs());
	EXPECT_EQ(probes.size(), 0u);
	}

	TEST_F(ProbeControllerTest, RequestProbeWhenBweDropNotRecent) {
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 2u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
	clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
	clock_.AdvanceTimeMilliseconds(kBitrateDropTimeoutMs + 1);
	probes = probe_controller_->RequestProbe(NowMs());
	EXPECT_EQ(probes.size(), 0u);
	}

	TEST_F(ProbeControllerTest, PeriodicProbing) {
	probe_controller_->EnablePeriodicAlrProbing(true);
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 2u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	int64_t start_time = clock_.TimeInMilliseconds();

	// Expect the controller to send a new probe after 5s has passed.
	probe_controller_->SetAlrStartTimeMs(start_time);
	clock_.AdvanceTimeMilliseconds(5000);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 1000);

	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());

	// The following probe should be sent at 10s into ALR.
	probe_controller_->SetAlrStartTimeMs(start_time);
	clock_.AdvanceTimeMilliseconds(4000);
	probes = probe_controller_->Process(NowMs());
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
	EXPECT_EQ(probes.size(), 0u);

	probe_controller_->SetAlrStartTimeMs(start_time);
	clock_.AdvanceTimeMilliseconds(1000);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 1u);
	probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
	EXPECT_EQ(probes.size(), 0u);
	}

	TEST_F(ProbeControllerTest, PeriodicProbingAfterReset) {
	probe_controller_.reset(
	new ProbeController(&field_trial_config_, &mock_rtc_event_log));
	int64_t alr_start_time = clock_.TimeInMilliseconds();

	probe_controller_->SetAlrStartTimeMs(alr_start_time);
	probe_controller_->EnablePeriodicAlrProbing(true);
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	probe_controller_->Reset(NowMs());

	clock_.AdvanceTimeMilliseconds(10000);
	probes = probe_controller_->Process(NowMs());
	// Since bitrates are not yet set, no probe is sent event though we are in ALR
	// mode.
	EXPECT_EQ(probes.size(), 0u);

	probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	kMaxBitrateBps, NowMs());
	EXPECT_EQ(probes.size(), 2u);

	// Make sure we use `kStartBitrateBps` as the estimated bitrate
	// until SetEstimatedBitrate is called with an updated estimate.
	clock_.AdvanceTimeMilliseconds(10000);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), kStartBitrateBps * 2);
	}

	TEST_F(ProbeControllerTest, TestExponentialProbingOverflow) {
	const int64_t kMbpsMultiplier = 1000000;
	auto probes = probe_controller_->SetBitrates(
	kMinBitrateBps, 10 * kMbpsMultiplier, 100 * kMbpsMultiplier, NowMs());
	// Verify that probe bitrate is capped at the specified max bitrate.
	probes =
	probe_controller_->SetEstimatedBitrate(60 * kMbpsMultiplier, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 100 * kMbpsMultiplier);
	// Verify that repeated probes aren't sent.
	probes =
	probe_controller_->SetEstimatedBitrate(100 * kMbpsMultiplier, NowMs());
	EXPECT_EQ(probes.size(), 0u);
	}

	TEST_F(ProbeControllerTest, TestAllocatedBitrateCap) {
	const int64_t kMbpsMultiplier = 1000000;
	const int64_t kMaxBitrateBps = 100 * kMbpsMultiplier;
	auto probes = probe_controller_->SetBitrates(
	kMinBitrateBps, 10 * kMbpsMultiplier, kMaxBitrateBps, NowMs());

	// Configure ALR for periodic probing.
	probe_controller_->EnablePeriodicAlrProbing(true);
	int64_t alr_start_time = clock_.TimeInMilliseconds();
	probe_controller_->SetAlrStartTimeMs(alr_start_time);

	int64_t estimated_bitrate_bps = kMaxBitrateBps / 10;
	probes =
	probe_controller_->SetEstimatedBitrate(estimated_bitrate_bps, NowMs());

	// Set a max allocated bitrate below the current estimate.
	int64_t max_allocated_bps = estimated_bitrate_bps - 1 * kMbpsMultiplier;
	probes =
	probe_controller_->OnMaxTotalAllocatedBitrate(max_allocated_bps, NowMs());
	EXPECT_TRUE(probes.empty()); // No probe since lower than current max.

	// Probes such as ALR capped at 2x the max allocation limit.
	clock_.AdvanceTimeMilliseconds(5000);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * max_allocated_bps);

	// Remove allocation limit.
	EXPECT_TRUE(
	probe_controller_->OnMaxTotalAllocatedBitrate(0, NowMs()).empty());
	clock_.AdvanceTimeMilliseconds(5000);
	probes = probe_controller_->Process(NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), estimated_bitrate_bps * 2);
	}

	TEST_F(ProbeControllerTest, ConfigurableProbingFieldTrial) {
	test::ScopedFieldTrials trials(
	"WebRTC-Bwe-ProbingConfiguration/"
	"p1:2,p2:5,step_size:3,further_probe_threshold:0.8,"
	"alloc_p1:2,alloc_p2/");
	probe_controller_.reset(
	new ProbeController(&field_trial_config_, &mock_rtc_event_log));
	auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
	5000000, NowMs());
	EXPECT_EQ(probes.size(), 2u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 600);
	EXPECT_EQ(probes[1].target_data_rate.bps(), 1500);

	// Repeated probe should only be sent when estimated bitrate climbs above
	// 0.8 * 5 * kStartBitrateBps = 1200.
	probes = probe_controller_->SetEstimatedBitrate(1100, NowMs());
	EXPECT_EQ(probes.size(), 0u);

	probes = probe_controller_->SetEstimatedBitrate(1250, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 3 * 1250);

	clock_.AdvanceTimeMilliseconds(5000);
	probes = probe_controller_->Process(NowMs());

	probe_controller_->SetAlrStartTimeMs(NowMs());
	probes = probe_controller_->OnMaxTotalAllocatedBitrate(200000, NowMs());
	EXPECT_EQ(probes.size(), 1u);
	EXPECT_EQ(probes[0].target_data_rate.bps(), 400000);
	}

	} // namespace test
	} // namespace webrtc