Add unittest for SmartDimMlAgent

This CL adds unittest for ml_agent.h/cc and ml_agent_util.h/cc.
It's very like model_unittest.cc, as ml_agent.h/cc is supposed to
replace current model_impl.h/cc and ml_service_client.h/cc in the
future.

Bug: 1018065
Test: run this unittest and pass
Change-Id: I9fda48f1235ca24220e8422a9de84e94537d0899
Cq-Depend: chromium:1903168
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1905044
Commit-Queue: Xinglong Luan <alanlxl@chromium.org>
Reviewed-by: Jia Meng <jiameng@chromium.org>
Reviewed-by: Andrew Moylan <amoylan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743890}

chrome/browser/chromeos/BUILD.gn

@@ -2998,6 +2998,8 @@ source_set("unit_tests") {
     "power/ml/boot_clock_unittest.cc",
     "power/ml/idle_event_notifier_unittest.cc",
     "power/ml/recent_events_counter_unittest.cc",
+    "power/ml/smart_dim/ml_agent_unittest.cc",
+    "power/ml/smart_dim/ml_agent_util_unittest.cc",
     "power/ml/smart_dim/model_unittest.cc",
     "power/ml/user_activity_manager_unittest.cc",
     "power/ml/user_activity_ukm_logger_helpers_unittest.cc",

chrome/browser/chromeos/power/ml/smart_dim/ml_agent.cc

@@ -336,6 +336,11 @@ void SmartDimMlAgent::CancelPreviousRequest() {
   dim_decision_callback_.Cancel();
 }
 
+void SmartDimMlAgent::ResetForTesting() {
+  builtin_worker_.Reset();
+  download_worker_.Reset();
+}
+
 SmartDimWorker* SmartDimMlAgent::GetWorker() {
   if (download_worker_.IsReady()) {
     // When download_worker_ is ready, builtin_worker_ is not useful any more,

chrome/browser/chromeos/power/ml/smart_dim/ml_agent.h

@@ -49,6 +49,9 @@ class SmartDimMlAgent {
                         const std::string& preprocessor_proto,
                         const std::string& model_flatbuffer);
 
+  // Called by ml_agent_unittest.cc to reset the builtin and download worker.
+  void ResetForTesting();
+
  protected:
   SmartDimMlAgent();
   virtual ~SmartDimMlAgent();

chrome/browser/chromeos/power/ml/smart_dim/ml_agent_util_unittest.cc

+// Copyright 2020 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 "chrome/browser/chromeos/power/ml/smart_dim/ml_agent_util.h"
+
+#include "base/containers/flat_map.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/path_service.h"
+#include "chromeos/test/chromeos_test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromeos {
+namespace power {
+namespace ml {
+
+namespace {
+std::string ReadMetadataFromTestData(const std::string& filename) {
+  base::FilePath json_path;
+  std::string json_string;
+
+  CHECK(
+      chromeos::test_utils::GetTestDataPath("smart_dim", filename, &json_path));
+  CHECK(base::ReadFileToString(json_path, &json_string));
+  return json_string;
+}
+}  // namespace
+
+TEST(SmartDimMlAgentUtilTest, ParseInvalidMetadata) {
+  const std::string json_string =
+      ReadMetadataFromTestData("invalid_model_metadata.json");
+  ASSERT_TRUE(json_string.size());
+
+  std::string metrics_model_name;
+  double threshold;
+  size_t expected_feature_size;
+  base::flat_map<std::string, int> inputs;
+  base::flat_map<std::string, int> outputs;
+
+  EXPECT_FALSE(ParseMetaInfoFromString(json_string, &metrics_model_name,
+                                       &threshold, &expected_feature_size,
+                                       &inputs, &outputs));
+  EXPECT_EQ(expected_feature_size, 0LU);
+  EXPECT_EQ(metrics_model_name, "");
+  EXPECT_DOUBLE_EQ(threshold, 0.0);
+  EXPECT_EQ(inputs.size(), 0LU);
+  EXPECT_EQ(outputs.size(), 0LU);
+}
+
+TEST(SmartDimMlAgentUtilTest, ParseValidMetadata) {
+  const std::string json_string =
+      ReadMetadataFromTestData("valid_model_metadata.json");
+  ASSERT_TRUE(json_string.size());
+
+  std::string metrics_model_name;
+  double threshold;
+  size_t expected_feature_size;
+  base::flat_map<std::string, int> inputs;
+  base::flat_map<std::string, int> outputs;
+
+  EXPECT_TRUE(ParseMetaInfoFromString(json_string, &metrics_model_name,
+                                      &threshold, &expected_feature_size,
+                                      &inputs, &outputs));
+  EXPECT_EQ(expected_feature_size, 343LU);
+  EXPECT_EQ(metrics_model_name, "smart_dim_model");
+  EXPECT_DOUBLE_EQ(threshold, 0.7);
+  EXPECT_EQ(inputs, (base::flat_map<std::string, int>{{"x", 3}, {"y", 4}}));
+  EXPECT_EQ(outputs, (base::flat_map<std::string, int>{{"z", 5}}));
+}
+
+}  // namespace ml
+}  // namespace power
+}  // namespace chromeos

chromeos/test/data/smart_dim/invalid_model_metadata.json

+{
+  "input_names": ["x", "y", "p"],
+  "input_nodes": [3, 4],
+  "output_names": ["z"],
+  "output_nodes": [5],
+  "threshold": 0.7,
+  "expected_feature_size": 343,
+  "metrics_model_name": "smart_dim_model"
+}
+

chromeos/test/data/smart_dim/valid_model_metadata.json

+{
+  "input_names": ["x", "y"],
+  "input_nodes": [3, 4],
+  "output_names": ["z"],
+  "output_nodes": [5],
+  "threshold": 0.7,
+  "expected_feature_size": 343,
+  "metrics_model_name": "smart_dim_model"
+}
+