Reland of: chromeos: Add CPU temperature reader

chromeos/system/cpu_temperature_reader_unittest.cc

Index: chromeos/system/cpu_temperature_reader_unittest.cc
diff --git a/chromeos/system/cpu_temperature_reader_unittest.cc b/chromeos/system/cpu_temperature_reader_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..54c00881c15a564dbd919d99ab013cf72dfd9bf1
--- /dev/null
+++ b/chromeos/system/cpu_temperature_reader_unittest.cc
@@ -0,0 +1,136 @@
+// Copyright 2017 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 "chromeos/system/cpu_temperature_reader.h"
+
+#include <algorithm>
+#include <string>
+
+#include "base/files/file.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromeos {
+namespace system {
+
+class CPUTemperatureReaderTest : public ::testing::Test {
+ public:
+  CPUTemperatureReaderTest() {
+    CHECK(dir_.CreateUniqueTempDir());
+    hwmon_path_ = dir_.GetPath();
+    reader_.set_hwmon_dir_for_test(hwmon_path_);
+  }
+
+  ~CPUTemperatureReaderTest() override = default;
+
+ protected:
+  using CPUTemperatureInfo = CPUTemperatureReader::CPUTemperatureInfo;
+
+  // Creates a subdirectory in |hwmon_path_| with name |name|. Returns the full
+  // path of the new subdirectory.
+  base::FilePath CreateHwmonSubdir(const std::string& name) {
+    base::FilePath subdir_path = hwmon_path_.Append(name);
+    CHECK(base::CreateDirectory(subdir_path));
+    return subdir_path;
+  }
+
+  // Creates a file at |path| containing data |contents|.
+  void CreateFileWithContents(const base::FilePath& path,
+                              const std::string& contents) {
+    CHECK_EQ(WriteFile(path, contents.data(), contents.size()),
+             static_cast<int>(contents.size()));
+  }
+
+  // Creates a temporary dir to act as the hwmon directory passed to |reader_|.
+  base::ScopedTempDir dir_;
+
+  // Path of the temporary dir created by |dir_|.
+  base::FilePath hwmon_path_;
+
+  // Instance of the class under test
+  CPUTemperatureReader reader_;
+};
+
+TEST_F(CPUTemperatureReaderTest, EmptyDir) {
+  base::FilePath subdir_empty = CreateHwmonSubdir("hwmon0");
+  base::FilePath subdir_not_temp = CreateHwmonSubdir("hwmon1");
+  CreateFileWithContents(subdir_not_temp.Append("not_cpu_temp"), "garbage");
+
+  EXPECT_EQ(0U, reader_.GetCPUTemperatures().size());
+}
+
+TEST_F(CPUTemperatureReaderTest, SingleDir) {
+  base::FilePath subdir = CreateHwmonSubdir("hwmon0");
+  CreateFileWithContents(subdir.Append("temp1_input"), "10000\n");
+
+  std::vector<CPUTemperatureInfo> cpu_temp_readings =
+      reader_.GetCPUTemperatures();
+
+  ASSERT_EQ(1U, cpu_temp_readings.size());
+  EXPECT_EQ(10.0f, cpu_temp_readings[0].temp_celsius);
+  EXPECT_EQ(subdir.Append("temp1_label").value(), cpu_temp_readings[0].label);
+}
+
+TEST_F(CPUTemperatureReaderTest, SingleDirWithLabel) {
+  base::FilePath subdir = CreateHwmonSubdir("hwmon0");
+  CreateFileWithContents(subdir.Append("temp2_input"), "20000\n");
+  CreateFileWithContents(subdir.Append("temp2_label"), "t2\n");
+
+  std::vector<CPUTemperatureInfo> cpu_temp_readings =
+      reader_.GetCPUTemperatures();
+
+  ASSERT_EQ(1U, cpu_temp_readings.size());
+  EXPECT_EQ(20.0f, cpu_temp_readings[0].temp_celsius);
+  EXPECT_EQ("t2", cpu_temp_readings[0].label);
+}
+
+TEST_F(CPUTemperatureReaderTest, SingleDirWithName) {
+  base::FilePath subdir = CreateHwmonSubdir("hwmon0");
+  CreateFileWithContents(subdir.Append("temp3_input"), "30000\n");
+  CreateFileWithContents(subdir.Append("temp3_label"), "\n");
+  CreateFileWithContents(subdir.Append("name"), "t3\n");
+
+  std::vector<CPUTemperatureInfo> cpu_temp_readings =
+      reader_.GetCPUTemperatures();
+
+  ASSERT_EQ(1U, cpu_temp_readings.size());
+  EXPECT_EQ(30.0f, cpu_temp_readings[0].temp_celsius);
+  EXPECT_EQ("t3", cpu_temp_readings[0].label);
+}
+
+TEST_F(CPUTemperatureReaderTest, MultipleDirs) {
+  base::FilePath subdir0 = CreateHwmonSubdir("hwmon0");
+  CreateFileWithContents(subdir0.Append("temp1_input"), "10000\n");
+
+  base::FilePath subdir1 = CreateHwmonSubdir("hwmon1");
+  CreateFileWithContents(subdir1.Append("temp2_input"), "20000\n");
+  CreateFileWithContents(subdir1.Append("temp2_label"), "t2\n");
+
+  // This should not result in a CPU temperature reading.
+  base::FilePath subdir2 = CreateHwmonSubdir("hwmon2");
+  CreateFileWithContents(subdir2.Append("not_cpu_temp"), "garbage");
+
+  base::FilePath subdir3 = CreateHwmonSubdir("hwmon3");
+  CreateFileWithContents(subdir3.Append("temp3_input"), "30000\n");
+  CreateFileWithContents(subdir3.Append("temp3_label"), "t3\n");
+
+  std::vector<CPUTemperatureInfo> cpu_temp_readings =
+      reader_.GetCPUTemperatures();
+
+  // The order in which these directories were read is not guaranteed. Sort them
+  // first.
+  std::sort(cpu_temp_readings.begin(), cpu_temp_readings.end());
+
+  ASSERT_EQ(3U, cpu_temp_readings.size());
+  EXPECT_EQ(10.0f, cpu_temp_readings[0].temp_celsius);
+  EXPECT_EQ(subdir0.Append("temp1_label").value(), cpu_temp_readings[0].label);
+  EXPECT_EQ(20.0f, cpu_temp_readings[1].temp_celsius);
+  EXPECT_EQ("t2", cpu_temp_readings[1].label);
+  EXPECT_EQ(30.0f, cpu_temp_readings[2].temp_celsius);
+  EXPECT_EQ("t3", cpu_temp_readings[2].label);
+}
+
+}  // namespace system
+}  // namespace chromeos