blob: d2e6cf0d1f658355d8b2f330e82879a8b6f5f25a [file] [log] [blame]
/*
* 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/trendline_estimator.h"
#include "rtc_base/random.h"
#include "test/gtest.h"
namespace webrtc {
namespace {
constexpr size_t kWindowSize = 20;
constexpr double kSmoothing = 0.0;
constexpr double kGain = 1;
constexpr int64_t kAvgTimeBetweenPackets = 10;
constexpr size_t kPacketCount = 2 * kWindowSize + 1;
class TrendlineEstimatorForTest : public TrendlineEstimator {
public:
using TrendlineEstimator::TrendlineEstimator;
using TrendlineEstimator::modified_trend;
};
void TestEstimator(double slope, double jitter_stddev, double tolerance) {
TrendlineEstimatorForTest estimator(kWindowSize, kSmoothing, kGain, nullptr);
Random random(0x1234567);
int64_t send_times[kPacketCount];
int64_t recv_times[kPacketCount];
int64_t send_start_time = random.Rand(1000000);
int64_t recv_start_time = random.Rand(1000000);
for (size_t i = 0; i < kPacketCount; ++i) {
send_times[i] = send_start_time + i * kAvgTimeBetweenPackets;
double latency = i * kAvgTimeBetweenPackets / (1 - slope);
double jitter = random.Gaussian(0, jitter_stddev);
recv_times[i] = recv_start_time + latency + jitter;
}
for (size_t i = 1; i < kPacketCount; ++i) {
double recv_delta = recv_times[i] - recv_times[i - 1];
double send_delta = send_times[i] - send_times[i - 1];
estimator.Update(recv_delta, send_delta, 0, recv_times[i], true);
if (i < kWindowSize)
EXPECT_NEAR(estimator.modified_trend(), 0, 0.001);
else
EXPECT_NEAR(estimator.modified_trend(), slope, tolerance);
}
}
} // namespace
TEST(TrendlineEstimator, PerfectLineSlopeOneHalf) {
TestEstimator(0.5, 0, 0.001);
}
TEST(TrendlineEstimator, PerfectLineSlopeMinusOne) {
TestEstimator(-1, 0, 0.001);
}
TEST(TrendlineEstimator, PerfectLineSlopeZero) {
TestEstimator(0, 0, 0.001);
}
TEST(TrendlineEstimator, JitteryLineSlopeOneHalf) {
TestEstimator(0.5, kAvgTimeBetweenPackets / 3.0, 0.01);
}
TEST(TrendlineEstimator, JitteryLineSlopeMinusOne) {
TestEstimator(-1, kAvgTimeBetweenPackets / 3.0, 0.075);
}
TEST(TrendlineEstimator, JitteryLineSlopeZero) {
TestEstimator(0, kAvgTimeBetweenPackets / 3.0, 0.02);
}
} // namespace webrtc