Split NQE to multiple files

net/nqe/network_quality_observation_unittest.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/nqe/network_quality_observation.h"
+
+#include <stddef.h>
+
+#include <vector>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "net/nqe/network_quality_observation_source.h"
+#include "net/nqe/observation_buffer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+
+namespace nqe {
+
+namespace {
+
+// Verifies that the percentiles are correctly computed. All observations have
+// the same timestamp.
+TEST(NetworkQualityObservationTest, PercentileSameTimestamps) {
+  internal::ObservationBuffer<int32_t> int_buffer(0.5);
+  internal::ObservationBuffer<base::TimeDelta> time_delta_buffer(0.5);
+  ASSERT_EQ(0u, int_buffer.Size());
+  ASSERT_LT(0u, int_buffer.Capacity());
+  ASSERT_EQ(0u, time_delta_buffer.Size());
+  ASSERT_LT(0u, time_delta_buffer.Capacity());
+
+  const base::TimeTicks now = base::TimeTicks::Now();
+
+  int32_t result;
+  base::TimeDelta time_delta_result;
+
+  // Percentiles should be unavailable when no observations are available.
+  EXPECT_FALSE(
+      int_buffer.GetPercentile(base::TimeTicks(), &result, 50,
+                               std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      base::TimeTicks(), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+
+  // Insert samples from {1,2,3,..., 100}. First insert odd samples, then even
+  // samples. This helps in verifying that the order of samples does not matter.
+  for (int i = 1; i <= 99; i += 2) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    EXPECT_TRUE(int_buffer.GetPercentile(
+        base::TimeTicks(), &result, 50,
+        std::vector<NetworkQualityObservationSource>()));
+    ASSERT_EQ(static_cast<size_t>(i / 2 + 1), int_buffer.Size());
+    EXPECT_TRUE(time_delta_buffer.GetPercentile(
+        base::TimeTicks(), &time_delta_result, 50,
+        std::vector<NetworkQualityObservationSource>()));
+    ASSERT_EQ(static_cast<size_t>(i / 2 + 1), time_delta_buffer.Size());
+  }
+
+  for (int i = 2; i <= 100; i += 2) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    EXPECT_TRUE(int_buffer.GetPercentile(
+        base::TimeTicks(), &result, 50,
+        std::vector<NetworkQualityObservationSource>()));
+    ASSERT_EQ(static_cast<size_t>(i / 2 + 50), int_buffer.Size());
+    EXPECT_TRUE(time_delta_buffer.GetPercentile(
+        base::TimeTicks(), &time_delta_result, 50,
+        std::vector<NetworkQualityObservationSource>()));
+    ASSERT_EQ(static_cast<size_t>(i / 2 + 50), time_delta_buffer.Size());
+  }
+
+  ASSERT_EQ(100u, int_buffer.Size());
+  ASSERT_EQ(100u, time_delta_buffer.Size());
+
+  for (int i = 0; i <= 100; ++i) {
+    // Checks if the difference between the two integers is less than 1. This is
+    // required because computed percentiles may be slightly different from
+    // what is expected due to floating point computation errors and integer
+    // rounding off errors.
+    EXPECT_TRUE(int_buffer.GetPercentile(
+        base::TimeTicks(), &result, i,
+        std::vector<NetworkQualityObservationSource>()));
+    EXPECT_TRUE(time_delta_buffer.GetPercentile(
+        base::TimeTicks(), &time_delta_result, i,
+        std::vector<NetworkQualityObservationSource>()));
+    EXPECT_NEAR(result, i, 1);
+    EXPECT_NEAR(time_delta_result.InMilliseconds(), i, 1);
+  }
+
+  EXPECT_FALSE(int_buffer.GetPercentile(
+      now + base::TimeDelta::FromSeconds(1), &result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      now + base::TimeDelta::FromSeconds(1), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+
+  // Percentiles should be unavailable when no observations are available.
+  int_buffer.Clear();
+  time_delta_buffer.Clear();
+  EXPECT_FALSE(
+      int_buffer.GetPercentile(base::TimeTicks(), &result, 50,
+                               std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      base::TimeTicks(), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+}
+
+// Verifies that the percentiles are correctly computed. Observations have
+// different timestamps with half the observations being very old and the rest
+// of them being very recent. Percentiles should factor in recent observations
+// much more heavily than older samples.
+TEST(NetworkQualityObservationTest, PercentileDifferentTimestamps) {
+  internal::ObservationBuffer<int32_t> int_buffer(0.5);
+  internal::ObservationBuffer<base::TimeDelta> time_delta_buffer(0.5);
+  const base::TimeTicks now = base::TimeTicks::Now();
+  const base::TimeTicks very_old = now - base::TimeDelta::FromDays(365);
+
+  int32_t result;
+  base::TimeDelta time_delta_result;
+
+  // Network quality should be unavailable when no observations are available.
+  EXPECT_FALSE(
+      int_buffer.GetPercentile(base::TimeTicks(), &result, 50,
+                               std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      base::TimeTicks(), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+
+  // First 50 samples have very old timestamp.
+  for (int i = 1; i <= 50; ++i) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, very_old, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), very_old,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  }
+
+  // Next 50 (i.e., from 51 to 100) have recent timestamp.
+  for (int i = 51; i <= 100; ++i) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  }
+
+  // Older samples have very little weight. So, all percentiles are >= 51
+  // (lowest value among recent observations).
+  for (int i = 1; i < 100; ++i) {
+    // Checks if the difference between the two integers is less than 1. This is
+    // required because computed percentiles may be slightly different from
+    // what is expected due to floating point computation errors and integer
+    // rounding off errors.
+    EXPECT_TRUE(int_buffer.GetPercentile(
+        base::TimeTicks(), &result, i,
+        std::vector<NetworkQualityObservationSource>()));
+    EXPECT_NEAR(result, 51 + 0.49 * i, 1);
+
+    EXPECT_TRUE(time_delta_buffer.GetPercentile(
+        base::TimeTicks(), &time_delta_result, i,
+        std::vector<NetworkQualityObservationSource>()));
+    EXPECT_NEAR(time_delta_result.InMilliseconds(), 51 + 0.49 * i, 1);
+  }
+
+  EXPECT_FALSE(int_buffer.GetPercentile(
+      now + base::TimeDelta::FromSeconds(1), &result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      now + base::TimeDelta::FromSeconds(1), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+}
+
+// Verifies that the percentiles are correctly computed when some of the
+// observation sources are disallowed. All observations have the same timestamp.
+TEST(NetworkQualityObservationTest, DisallowedObservationSources) {
+  internal::ObservationBuffer<int32_t> int_buffer(0.5);
+  internal::ObservationBuffer<base::TimeDelta> time_delta_buffer(0.5);
+  const base::TimeTicks now = base::TimeTicks::Now();
+
+  int32_t result;
+  base::TimeDelta time_delta_result;
+
+  // Network quality should be unavailable when no observations are available.
+  EXPECT_FALSE(
+      int_buffer.GetPercentile(base::TimeTicks(), &result, 50,
+                               std::vector<NetworkQualityObservationSource>()));
+  EXPECT_FALSE(time_delta_buffer.GetPercentile(
+      base::TimeTicks(), &time_delta_result, 50,
+      std::vector<NetworkQualityObservationSource>()));
+
+  // Insert samples from {1,2,3,..., 100}. First insert odd samples, then even
+  // samples. This helps in verifying that the order of samples does not matter.
+  for (int i = 1; i <= 99; i += 2) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  }
+
+  // Add samples for TCP and QUIC observations which should not be taken into
+  // account when computing the percentile.
+  for (int i = 1; i <= 99; i += 2) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        10000, now, NETWORK_QUALITY_OBSERVATION_SOURCE_TCP));
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        10000, now, NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(10000), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_TCP));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(10000), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC));
+  }
+
+  for (int i = 2; i <= 100; i += 2) {
+    int_buffer.AddObservation(internal::Observation<int32_t>(
+        i, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+    time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+        base::TimeDelta::FromMilliseconds(i), now,
+        NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  }
+
+  std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
+  disallowed_observation_sources.push_back(
+      NETWORK_QUALITY_OBSERVATION_SOURCE_TCP);
+  disallowed_observation_sources.push_back(
+      NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC);
+
+  for (int i = 0; i <= 100; ++i) {
+    // Checks if the difference between the two integers is less than 1. This is
+    // required because computed percentiles may be slightly different from
+    // what is expected due to floating point computation errors and integer
+    // rounding off errors.
+    EXPECT_TRUE(int_buffer.GetPercentile(base::TimeTicks(), &result, i,
+                                         disallowed_observation_sources));
+    EXPECT_NEAR(result, i, 1);
+    EXPECT_TRUE(
+        time_delta_buffer.GetPercentile(base::TimeTicks(), &time_delta_result,
+                                        i, disallowed_observation_sources));
+    EXPECT_NEAR(time_delta_result.InMilliseconds(), i, 1);
+  }
+
+  // Now check the percentile value for TCP and QUIC observations.
+  disallowed_observation_sources.clear();
+  disallowed_observation_sources.push_back(
+      NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST);
+  for (int i = 0; i <= 100; ++i) {
+    // Checks if the difference between the two integers is less than 1. This is
+    // required because computed percentiles may be slightly different from
+    // what is expected due to floating point computation errors and integer
+    // rounding off errors.
+    EXPECT_TRUE(int_buffer.GetPercentile(base::TimeTicks(), &result, i,
+                                         disallowed_observation_sources));
+    EXPECT_NEAR(result, 10000, 1);
+    EXPECT_TRUE(
+        time_delta_buffer.GetPercentile(base::TimeTicks(), &time_delta_result,
+                                        i, disallowed_observation_sources));
+    EXPECT_NEAR(time_delta_result.InMilliseconds(), 10000, 1);
+  }
+}
+
+TEST(NetworkQualityObservationTest, TestGetMedianRTTSince) {
+  internal::ObservationBuffer<int32_t> int_buffer(0.5);
+  internal::ObservationBuffer<base::TimeDelta> time_delta_buffer(0.5);
+  base::TimeTicks now = base::TimeTicks::Now();
+  base::TimeTicks old = now - base::TimeDelta::FromMilliseconds(1);
+  ASSERT_NE(old, now);
+
+  // First sample has very old timestamp.
+  int_buffer.AddObservation(internal::Observation<int32_t>(
+      1, old, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+      base::TimeDelta::FromMilliseconds(1), old,
+      NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+
+  int_buffer.AddObservation(internal::Observation<int32_t>(
+      100, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+  time_delta_buffer.AddObservation(internal::Observation<base::TimeDelta>(
+      base::TimeDelta::FromMilliseconds(100), now,
+      NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST));
+
+  const struct {
+    base::TimeTicks start_timestamp;
+    bool expect_network_quality_available;
+    base::TimeDelta expected_url_request_rtt;
+    int32_t expected_downstream_throughput;
+  } tests[] = {
+      {now + base::TimeDelta::FromSeconds(10), false,
+       base::TimeDelta::FromMilliseconds(0), 0},
+      {now, true, base::TimeDelta::FromMilliseconds(100), 100},
+      {now - base::TimeDelta::FromMicroseconds(500), true,
+       base::TimeDelta::FromMilliseconds(100), 100},
+
+  };
+
+  for (const auto& test : tests) {
+    base::TimeDelta url_request_rtt;
+    int32_t downstream_throughput_kbps;
+    std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
+
+    EXPECT_EQ(
+        test.expect_network_quality_available,
+        time_delta_buffer.GetPercentile(test.start_timestamp, &url_request_rtt,
+                                        50, disallowed_observation_sources));
+    EXPECT_EQ(test.expect_network_quality_available,
+              int_buffer.GetPercentile(test.start_timestamp,
+                                       &downstream_throughput_kbps, 50,
+                                       disallowed_observation_sources));
+
+    if (test.expect_network_quality_available) {
+      EXPECT_EQ(test.expected_url_request_rtt, url_request_rtt);
+      EXPECT_EQ(test.expected_downstream_throughput,
+                downstream_throughput_kbps);
+    }
+  }
+}
+
+}  // namespace
+
+}  // namespace nqe
+
+}  // namespace net