Introduce MetricsLogger to separate logging and export logic

Bug: b/246095034
Change-Id: If870016b87126feefb9c63b1544091f0855e169f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/276600
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38180}
diff --git a/api/test/metrics/BUILD.gn b/api/test/metrics/BUILD.gn
index a7283cd..4369800 100644
--- a/api/test/metrics/BUILD.gn
+++ b/api/test/metrics/BUILD.gn
@@ -16,6 +16,7 @@
     ":global_metrics_logger_and_exporter",
     ":metric",
     ":metrics_exporter",
+    ":metrics_logger",
     ":metrics_logger_and_exporter",
     ":stdout_metrics_exporter",
   ]
@@ -27,6 +28,7 @@
 
     deps = [
       ":metrics_logger_and_exporter_test",
+      ":metrics_logger_test",
       ":print_result_proxy_metrics_exporter_test",
       ":stdout_metrics_exporter_test",
     ]
@@ -50,6 +52,22 @@
   deps = [ "../../../api/units:timestamp" ]
 }
 
+rtc_library("metrics_logger") {
+  visibility = [ "*" ]
+  sources = [
+    "metrics_logger.cc",
+    "metrics_logger.h",
+  ]
+  deps = [
+    ":metric",
+    "../..:array_view",
+    "../../../rtc_base/synchronization:mutex",
+    "../../../system_wrappers",
+    "../../numerics",
+  ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+}
+
 rtc_library("metrics_exporter") {
   visibility = [ "*" ]
   sources = [ "metrics_exporter.h" ]
@@ -147,6 +165,7 @@
   deps = [
     ":metric",
     ":metrics_exporter",
+    ":metrics_logger",
     "../../../rtc_base:checks",
     "../../../rtc_base:logging",
     "../../../rtc_base/synchronization:mutex",
@@ -175,6 +194,19 @@
 }
 
 if (rtc_include_tests) {
+  rtc_library("metrics_logger_test") {
+    testonly = true
+    sources = [ "metrics_logger_test.cc" ]
+    deps = [
+      ":metric",
+      ":metrics_logger",
+      "../../../system_wrappers",
+      "../../../test:test_support",
+      "../../numerics",
+    ]
+    absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
+  }
+
   rtc_library("stdout_metrics_exporter_test") {
     testonly = true
     sources = [ "stdout_metrics_exporter_test.cc" ]
diff --git a/api/test/metrics/DEPS b/api/test/metrics/DEPS
index d0def60..a1c845b 100644
--- a/api/test/metrics/DEPS
+++ b/api/test/metrics/DEPS
@@ -3,4 +3,8 @@
     "+rtc_base/synchronization/mutex.h",
     "+system_wrappers/include/clock.h",
   ],
+  "metrics_logger\.h": [
+    "+rtc_base/synchronization/mutex.h",
+    "+system_wrappers/include/clock.h",
+  ],
 }
diff --git a/api/test/metrics/metrics_logger.cc b/api/test/metrics/metrics_logger.cc
new file mode 100644
index 0000000..c207505
--- /dev/null
+++ b/api/test/metrics/metrics_logger.cc
@@ -0,0 +1,107 @@
+/*
+ *  Copyright (c) 2022 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 "api/test/metrics/metrics_logger.h"
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/numerics/samples_stats_counter.h"
+#include "api/test/metrics/metric.h"
+#include "rtc_base/synchronization/mutex.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+Metric::Stats ToStats(const SamplesStatsCounter& values) {
+  if (values.IsEmpty()) {
+    return Metric::Stats();
+  }
+  return Metric::Stats{.mean = values.GetAverage(),
+                       .stddev = values.GetStandardDeviation(),
+                       .min = values.GetMin(),
+                       .max = values.GetMax()};
+}
+
+}  // namespace
+
+void DefaultMetricsLogger::LogSingleValueMetric(
+    absl::string_view name,
+    absl::string_view test_case_name,
+    double value,
+    Unit unit,
+    ImprovementDirection improvement_direction,
+    std::map<std::string, std::string> metadata) {
+  MutexLock lock(&mutex_);
+  metrics_.push_back(Metric{
+      .name = std::string(name),
+      .unit = unit,
+      .improvement_direction = improvement_direction,
+      .test_case = std::string(test_case_name),
+      .metric_metadata = std::move(metadata),
+      .time_series =
+          Metric::TimeSeries{.samples = std::vector{Metric::TimeSeries::Sample{
+                                 .timestamp = Now(), .value = value}}},
+      .stats = Metric::Stats{
+          .mean = value, .stddev = absl::nullopt, .min = value, .max = value}});
+}
+
+void DefaultMetricsLogger::LogMetric(
+    absl::string_view name,
+    absl::string_view test_case_name,
+    const SamplesStatsCounter& values,
+    Unit unit,
+    ImprovementDirection improvement_direction,
+    std::map<std::string, std::string> metadata) {
+  MutexLock lock(&mutex_);
+  Metric::TimeSeries time_series;
+  for (const SamplesStatsCounter::StatsSample& sample :
+       values.GetTimedSamples()) {
+    time_series.samples.push_back(
+        Metric::TimeSeries::Sample{.timestamp = sample.time,
+                                   .value = sample.value,
+                                   .sample_metadata = sample.metadata});
+  }
+
+  metrics_.push_back(Metric{.name = std::string(name),
+                            .unit = unit,
+                            .improvement_direction = improvement_direction,
+                            .test_case = std::string(test_case_name),
+                            .metric_metadata = std::move(metadata),
+                            .time_series = std::move(time_series),
+                            .stats = ToStats(values)});
+}
+
+void DefaultMetricsLogger::LogMetric(
+    absl::string_view name,
+    absl::string_view test_case_name,
+    const Metric::Stats& metric_stats,
+    Unit unit,
+    ImprovementDirection improvement_direction,
+    std::map<std::string, std::string> metadata) {
+  MutexLock lock(&mutex_);
+  metrics_.push_back(Metric{.name = std::string(name),
+                            .unit = unit,
+                            .improvement_direction = improvement_direction,
+                            .test_case = std::string(test_case_name),
+                            .metric_metadata = std::move(metadata),
+                            .time_series = Metric::TimeSeries{.samples = {}},
+                            .stats = std::move(metric_stats)});
+}
+
+Timestamp DefaultMetricsLogger::Now() {
+  return clock_->CurrentTime();
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/api/test/metrics/metrics_logger.h b/api/test/metrics/metrics_logger.h
new file mode 100644
index 0000000..6839bad
--- /dev/null
+++ b/api/test/metrics/metrics_logger.h
@@ -0,0 +1,111 @@
+/*
+ *  Copyright (c) 2022 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.
+ */
+
+#ifndef API_TEST_METRICS_METRICS_LOGGER_H_
+#define API_TEST_METRICS_METRICS_LOGGER_H_
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/numerics/samples_stats_counter.h"
+#include "api/test/metrics/metric.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "system_wrappers/include/clock.h"
+
+namespace webrtc {
+namespace test {
+
+// Provides API to log and collect performance metrics.
+class MetricsLogger {
+ public:
+  virtual ~MetricsLogger() = default;
+
+  // Adds a metric with a single value.
+  // `metadata` - metric's level metadata to add.
+  virtual void LogSingleValueMetric(
+      absl::string_view name,
+      absl::string_view test_case_name,
+      double value,
+      Unit unit,
+      ImprovementDirection improvement_direction,
+      std::map<std::string, std::string> metadata = {}) = 0;
+
+  // Adds metrics with a time series created based on the provided `values`.
+  // `metadata` - metric's level metadata to add.
+  virtual void LogMetric(absl::string_view name,
+                         absl::string_view test_case_name,
+                         const SamplesStatsCounter& values,
+                         Unit unit,
+                         ImprovementDirection improvement_direction,
+                         std::map<std::string, std::string> metadata = {}) = 0;
+
+  // Adds metric with a time series with only stats object and without actual
+  // collected values.
+  // `metadata` - metric's level metadata to add.
+  virtual void LogMetric(absl::string_view name,
+                         absl::string_view test_case_name,
+                         const Metric::Stats& metric_stats,
+                         Unit unit,
+                         ImprovementDirection improvement_direction,
+                         std::map<std::string, std::string> metadata = {}) = 0;
+
+  // Returns all metrics collected by this logger.
+  virtual std::vector<Metric> GetCollectedMetrics() const = 0;
+};
+
+class DefaultMetricsLogger : public MetricsLogger {
+ public:
+  explicit DefaultMetricsLogger(webrtc::Clock* clock) : clock_(clock) {}
+  ~DefaultMetricsLogger() override = default;
+
+  void LogSingleValueMetric(
+      absl::string_view name,
+      absl::string_view test_case_name,
+      double value,
+      Unit unit,
+      ImprovementDirection improvement_direction,
+      std::map<std::string, std::string> metadata = {}) override;
+
+  void LogMetric(absl::string_view name,
+                 absl::string_view test_case_name,
+                 const SamplesStatsCounter& values,
+                 Unit unit,
+                 ImprovementDirection improvement_direction,
+                 std::map<std::string, std::string> metadata = {}) override;
+
+  void LogMetric(absl::string_view name,
+                 absl::string_view test_case_name,
+                 const Metric::Stats& metric_stats,
+                 Unit unit,
+                 ImprovementDirection improvement_direction,
+                 std::map<std::string, std::string> metadata = {}) override;
+
+  // Returns all metrics collected by this logger.
+  std::vector<Metric> GetCollectedMetrics() const override {
+    MutexLock lock(&mutex_);
+    return metrics_;
+  }
+
+ private:
+  webrtc::Timestamp Now();
+
+  webrtc::Clock* const clock_;
+
+  mutable Mutex mutex_;
+  std::vector<Metric> metrics_ RTC_GUARDED_BY(mutex_);
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // API_TEST_METRICS_METRICS_LOGGER_H_
diff --git a/api/test/metrics/metrics_logger_and_exporter.h b/api/test/metrics/metrics_logger_and_exporter.h
index 4541790..562aa6e 100644
--- a/api/test/metrics/metrics_logger_and_exporter.h
+++ b/api/test/metrics/metrics_logger_and_exporter.h
@@ -21,6 +21,7 @@
 #include "api/numerics/samples_stats_counter.h"
 #include "api/test/metrics/metric.h"
 #include "api/test/metrics/metrics_exporter.h"
+#include "api/test/metrics/metrics_logger.h"
 #include "rtc_base/synchronization/mutex.h"
 #include "system_wrappers/include/clock.h"
 
@@ -29,7 +30,7 @@
 
 // Combines metrics logging and exporting to provide simple API to automatically
 // export metrics at the end of the scope.
-class MetricsLoggerAndExporter {
+class MetricsLoggerAndExporter : public MetricsLogger {
  public:
   // `crash_on_export_failure` - makes MetricsLoggerAndExporter to crash if
   // any of exporters failed to export data.
@@ -40,16 +41,17 @@
       : clock_(clock),
         crash_on_export_failure_(crash_on_export_failure),
         exporters_(std::move(exporters)) {}
-  ~MetricsLoggerAndExporter();
+  ~MetricsLoggerAndExporter() override;
 
   // Adds a metric with a single value.
   // `metadata` - metric's level metadata to add.
-  void LogSingleValueMetric(absl::string_view name,
-                            absl::string_view test_case_name,
-                            double value,
-                            Unit unit,
-                            ImprovementDirection improvement_direction,
-                            std::map<std::string, std::string> metadata = {});
+  void LogSingleValueMetric(
+      absl::string_view name,
+      absl::string_view test_case_name,
+      double value,
+      Unit unit,
+      ImprovementDirection improvement_direction,
+      std::map<std::string, std::string> metadata = {}) override;
 
   // Adds metrics with a time series created based on the provided `values`.
   // `metadata` - metric's level metadata to add.
@@ -58,7 +60,7 @@
                  const SamplesStatsCounter& values,
                  Unit unit,
                  ImprovementDirection improvement_direction,
-                 std::map<std::string, std::string> metadata = {});
+                 std::map<std::string, std::string> metadata = {}) override;
 
   // Adds metric with a time series with only stats object and without actual
   // collected values.
@@ -68,10 +70,10 @@
                  const Metric::Stats& metric_stats,
                  Unit unit,
                  ImprovementDirection improvement_direction,
-                 std::map<std::string, std::string> metadata = {});
+                 std::map<std::string, std::string> metadata = {}) override;
 
   // Returns all metrics collected by this logger.
-  std::vector<Metric> GetCollectedMetrics() const {
+  std::vector<Metric> GetCollectedMetrics() const override {
     MutexLock lock(&mutex_);
     return metrics_;
   }
diff --git a/api/test/metrics/metrics_logger_test.cc b/api/test/metrics/metrics_logger_test.cc
new file mode 100644
index 0000000..9a59446
--- /dev/null
+++ b/api/test/metrics/metrics_logger_test.cc
@@ -0,0 +1,249 @@
+/*
+ *  Copyright (c) 2022 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 "api/test/metrics/metrics_logger.h"
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/numerics/samples_stats_counter.h"
+#include "api/test/metrics/metric.h"
+#include "system_wrappers/include/clock.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+using ::testing::Eq;
+using ::testing::IsEmpty;
+
+std::map<std::string, std::string> DefaultMetadata() {
+  return std::map<std::string, std::string>{{"key", "value"}};
+}
+
+TEST(DefaultMetricsLoggerTest, LogSingleValueMetricRecordsMetric) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  logger.LogSingleValueMetric(
+      "metric_name", "test_case_name",
+      /*value=*/10, Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+      std::map<std::string, std::string>{{"key", "value"}});
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(1lu));
+  const Metric& metric = metrics[0];
+  EXPECT_THAT(metric.name, Eq("metric_name"));
+  EXPECT_THAT(metric.test_case, Eq("test_case_name"));
+  EXPECT_THAT(metric.unit, Eq(Unit::kMilliseconds));
+  EXPECT_THAT(metric.improvement_direction,
+              Eq(ImprovementDirection::kBiggerIsBetter));
+  EXPECT_THAT(metric.metric_metadata,
+              Eq(std::map<std::string, std::string>{{"key", "value"}}));
+  ASSERT_THAT(metric.time_series.samples.size(), Eq(1lu));
+  EXPECT_THAT(metric.time_series.samples[0].value, Eq(10.0));
+  EXPECT_THAT(metric.time_series.samples[0].sample_metadata,
+              Eq(std::map<std::string, std::string>{}));
+  ASSERT_THAT(metric.stats.mean, absl::optional<double>(10.0));
+  ASSERT_THAT(metric.stats.stddev, absl::nullopt);
+  ASSERT_THAT(metric.stats.min, absl::optional<double>(10.0));
+  ASSERT_THAT(metric.stats.max, absl::optional<double>(10.0));
+}
+
+TEST(DefaultMetricsLoggerTest, LogMetricWithSamplesStatsCounterRecordsMetric) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+
+  SamplesStatsCounter values;
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 10,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata =
+          std::map<std::string, std::string>{{"point_key1", "value1"}}});
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 20,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata =
+          std::map<std::string, std::string>{{"point_key2", "value2"}}});
+  logger.LogMetric("metric_name", "test_case_name", values, Unit::kMilliseconds,
+                   ImprovementDirection::kBiggerIsBetter,
+                   std::map<std::string, std::string>{{"key", "value"}});
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(1lu));
+  const Metric& metric = metrics[0];
+  EXPECT_THAT(metric.name, Eq("metric_name"));
+  EXPECT_THAT(metric.test_case, Eq("test_case_name"));
+  EXPECT_THAT(metric.unit, Eq(Unit::kMilliseconds));
+  EXPECT_THAT(metric.improvement_direction,
+              Eq(ImprovementDirection::kBiggerIsBetter));
+  EXPECT_THAT(metric.metric_metadata,
+              Eq(std::map<std::string, std::string>{{"key", "value"}}));
+  ASSERT_THAT(metric.time_series.samples.size(), Eq(2lu));
+  EXPECT_THAT(metric.time_series.samples[0].value, Eq(10.0));
+  EXPECT_THAT(metric.time_series.samples[0].sample_metadata,
+              Eq(std::map<std::string, std::string>{{"point_key1", "value1"}}));
+  EXPECT_THAT(metric.time_series.samples[1].value, Eq(20.0));
+  EXPECT_THAT(metric.time_series.samples[1].sample_metadata,
+              Eq(std::map<std::string, std::string>{{"point_key2", "value2"}}));
+  ASSERT_THAT(metric.stats.mean, absl::optional<double>(15.0));
+  ASSERT_THAT(metric.stats.stddev, absl::optional<double>(5.0));
+  ASSERT_THAT(metric.stats.min, absl::optional<double>(10.0));
+  ASSERT_THAT(metric.stats.max, absl::optional<double>(20.0));
+}
+
+TEST(DefaultMetricsLoggerTest,
+     LogMetricWithEmptySamplesStatsCounterRecordsEmptyMetric) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  SamplesStatsCounter values;
+  logger.LogMetric("metric_name", "test_case_name", values, Unit::kUnitless,
+                   ImprovementDirection::kBiggerIsBetter, DefaultMetadata());
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(1lu));
+  EXPECT_THAT(metrics[0].name, Eq("metric_name"));
+  EXPECT_THAT(metrics[0].test_case, Eq("test_case_name"));
+  EXPECT_THAT(metrics[0].time_series.samples, IsEmpty());
+  ASSERT_THAT(metrics[0].stats.mean, Eq(absl::nullopt));
+  ASSERT_THAT(metrics[0].stats.stddev, Eq(absl::nullopt));
+  ASSERT_THAT(metrics[0].stats.min, Eq(absl::nullopt));
+  ASSERT_THAT(metrics[0].stats.max, Eq(absl::nullopt));
+}
+
+TEST(DefaultMetricsLoggerTest, LogMetricWithStatsRecordsMetric) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  Metric::Stats metric_stats{.mean = 15, .stddev = 5, .min = 10, .max = 20};
+  logger.LogMetric("metric_name", "test_case_name", metric_stats,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   std::map<std::string, std::string>{{"key", "value"}});
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(1lu));
+  const Metric& metric = metrics[0];
+  EXPECT_THAT(metric.name, Eq("metric_name"));
+  EXPECT_THAT(metric.test_case, Eq("test_case_name"));
+  EXPECT_THAT(metric.unit, Eq(Unit::kMilliseconds));
+  EXPECT_THAT(metric.improvement_direction,
+              Eq(ImprovementDirection::kBiggerIsBetter));
+  EXPECT_THAT(metric.metric_metadata,
+              Eq(std::map<std::string, std::string>{{"key", "value"}}));
+  ASSERT_THAT(metric.time_series.samples.size(), Eq(0lu));
+  ASSERT_THAT(metric.stats.mean, absl::optional<double>(15.0));
+  ASSERT_THAT(metric.stats.stddev, absl::optional<double>(5.0));
+  ASSERT_THAT(metric.stats.min, absl::optional<double>(10.0));
+  ASSERT_THAT(metric.stats.max, absl::optional<double>(20.0));
+}
+
+TEST(DefaultMetricsLoggerTest, LogSingleValueMetricRecordsMultipleMetrics) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+
+  logger.LogSingleValueMetric("metric_name1", "test_case_name1",
+                              /*value=*/10, Unit::kMilliseconds,
+                              ImprovementDirection::kBiggerIsBetter,
+                              DefaultMetadata());
+  logger.LogSingleValueMetric("metric_name2", "test_case_name2",
+                              /*value=*/10, Unit::kMilliseconds,
+                              ImprovementDirection::kBiggerIsBetter,
+                              DefaultMetadata());
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(2lu));
+  EXPECT_THAT(metrics[0].name, Eq("metric_name1"));
+  EXPECT_THAT(metrics[0].test_case, Eq("test_case_name1"));
+  EXPECT_THAT(metrics[1].name, Eq("metric_name2"));
+  EXPECT_THAT(metrics[1].test_case, Eq("test_case_name2"));
+}
+
+TEST(DefaultMetricsLoggerTest,
+     LogMetricWithSamplesStatsCounterRecordsMultipleMetrics) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  SamplesStatsCounter values;
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 10,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata = DefaultMetadata()});
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 20,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata = DefaultMetadata()});
+
+  logger.LogMetric("metric_name1", "test_case_name1", values,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+  logger.LogMetric("metric_name2", "test_case_name2", values,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(2lu));
+  EXPECT_THAT(metrics[0].name, Eq("metric_name1"));
+  EXPECT_THAT(metrics[0].test_case, Eq("test_case_name1"));
+  EXPECT_THAT(metrics[1].name, Eq("metric_name2"));
+  EXPECT_THAT(metrics[1].test_case, Eq("test_case_name2"));
+}
+
+TEST(DefaultMetricsLoggerTest, LogMetricWithStatsRecordsMultipleMetrics) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  Metric::Stats metric_stats{.mean = 15, .stddev = 5, .min = 10, .max = 20};
+
+  logger.LogMetric("metric_name1", "test_case_name1", metric_stats,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+  logger.LogMetric("metric_name2", "test_case_name2", metric_stats,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(2lu));
+  EXPECT_THAT(metrics[0].name, Eq("metric_name1"));
+  EXPECT_THAT(metrics[0].test_case, Eq("test_case_name1"));
+  EXPECT_THAT(metrics[1].name, Eq("metric_name2"));
+  EXPECT_THAT(metrics[1].test_case, Eq("test_case_name2"));
+}
+
+TEST(DefaultMetricsLoggerTest,
+     LogMetricThroughtAllMethodsAccumulateAllMetrics) {
+  DefaultMetricsLogger logger(Clock::GetRealTimeClock());
+  SamplesStatsCounter values;
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 10,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata = DefaultMetadata()});
+  values.AddSample(SamplesStatsCounter::StatsSample{
+      .value = 20,
+      .time = Clock::GetRealTimeClock()->CurrentTime(),
+      .metadata = DefaultMetadata()});
+  Metric::Stats metric_stats{.mean = 15, .stddev = 5, .min = 10, .max = 20};
+
+  logger.LogSingleValueMetric("metric_name1", "test_case_name1",
+                              /*value=*/10, Unit::kMilliseconds,
+                              ImprovementDirection::kBiggerIsBetter,
+                              DefaultMetadata());
+  logger.LogMetric("metric_name2", "test_case_name2", values,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+  logger.LogMetric("metric_name3", "test_case_name3", metric_stats,
+                   Unit::kMilliseconds, ImprovementDirection::kBiggerIsBetter,
+                   DefaultMetadata());
+
+  std::vector<Metric> metrics = logger.GetCollectedMetrics();
+  ASSERT_THAT(metrics.size(), Eq(3lu));
+  EXPECT_THAT(metrics[0].name, Eq("metric_name1"));
+  EXPECT_THAT(metrics[0].test_case, Eq("test_case_name1"));
+  EXPECT_THAT(metrics[1].name, Eq("metric_name2"));
+  EXPECT_THAT(metrics[1].test_case, Eq("test_case_name2"));
+  EXPECT_THAT(metrics[2].name, Eq("metric_name3"));
+  EXPECT_THAT(metrics[2].test_case, Eq("test_case_name3"));
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace webrtc