Pass arrival time as an int64_t rather than a double to the MedianSlopeEstimator to avoid precision loss.
Also clean up the unit test.
BUG=webrtc:6892
Committed: https://crrev.com/ebcbcc3b2451f5c4fb07f7b37815bd54f364d057
Cr-Original-Commit-Position: refs/heads/master@{#15634}
Review-Url: https://codereview.webrtc.org/2578543002
Cr-Commit-Position: refs/heads/master@{#15650}
diff --git a/webrtc/modules/congestion_controller/median_slope_estimator_unittest.cc b/webrtc/modules/congestion_controller/median_slope_estimator_unittest.cc
index ef942f1..5be0e9b 100644
--- a/webrtc/modules/congestion_controller/median_slope_estimator_unittest.cc
+++ b/webrtc/modules/congestion_controller/median_slope_estimator_unittest.cc
@@ -18,96 +18,55 @@
constexpr size_t kWindowSize = 20;
constexpr double kGain = 1;
constexpr int64_t kAvgTimeBetweenPackets = 10;
+constexpr size_t kPacketCount = 2 * kWindowSize + 1;
+
+void TestEstimator(double slope, double jitter_stddev, double tolerance) {
+ MedianSlopeEstimator estimator(kWindowSize, kGain);
+ 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, recv_times[i]);
+ if (i < kWindowSize)
+ EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
+ else
+ EXPECT_NEAR(estimator.trendline_slope(), slope, tolerance);
+ }
+}
} // namespace
TEST(MedianSlopeEstimator, PerfectLineSlopeOneHalf) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = 2 * send_delta;
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- if (i < kWindowSize)
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
- else
- EXPECT_NEAR(estimator.trendline_slope(), 0.5, 0.001);
- }
+ TestEstimator(0.5, 0, 0.001);
}
TEST(MedianSlopeEstimator, PerfectLineSlopeMinusOne) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = 0.5 * send_delta;
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- if (i < kWindowSize)
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
- else
- EXPECT_NEAR(estimator.trendline_slope(), -1, 0.001);
- }
+ TestEstimator(-1, 0, 0.001);
}
TEST(MedianSlopeEstimator, PerfectLineSlopeZero) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = send_delta;
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
- }
+ TestEstimator(0, 0, 0.001);
}
TEST(MedianSlopeEstimator, JitteryLineSlopeOneHalf) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = 2 * send_delta + rand.Gaussian(0, send_delta / 3);
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- if (i < kWindowSize)
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
- else
- EXPECT_NEAR(estimator.trendline_slope(), 0.5, 0.1);
- }
+ TestEstimator(0.5, kAvgTimeBetweenPackets / 3.0, 0.01);
}
TEST(MedianSlopeEstimator, JitteryLineSlopeMinusOne) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = 0.5 * send_delta + rand.Gaussian(0, send_delta / 20);
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- if (i < kWindowSize)
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.001);
- else
- EXPECT_NEAR(estimator.trendline_slope(), -1, 0.1);
- }
+ TestEstimator(-1, kAvgTimeBetweenPackets / 3.0, 0.05);
}
TEST(MedianSlopeEstimator, JitteryLineSlopeZero) {
- MedianSlopeEstimator estimator(kWindowSize, kGain);
- Random rand(0x1234567);
- double now_ms = rand.Rand<double>() * 10000;
- for (size_t i = 1; i < 2 * kWindowSize; i++) {
- double send_delta = rand.Rand<double>() * 2 * kAvgTimeBetweenPackets;
- double recv_delta = send_delta + rand.Gaussian(0, send_delta / 5);
- now_ms += recv_delta;
- estimator.Update(recv_delta, send_delta, now_ms);
- EXPECT_NEAR(estimator.trendline_slope(), 0, 0.1);
- }
+ TestEstimator(0, kAvgTimeBetweenPackets / 3.0, 0.02);
}
} // namespace webrtc
