base/timer/hi_res_timer_manager_unittest.cc

// Copyright (c) 2012 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 "base/timer/hi_res_timer_manager.h"

#include <memory>
#include <utility>

#include "base/power_monitor/power_monitor.h"
#include "base/power_monitor/power_monitor_device_source.h"
#include "base/test/scoped_task_environment.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

#if defined(OS_WIN)
TEST(HiResTimerManagerTest, ToggleOnOff) {
  // The power monitor creates Window to receive power notifications from
  // Windows, which makes this test flaky if you run while the machine
  // goes in or out of AC power.
  test::ScopedTaskEnvironment scoped_task_environment(
      test::ScopedTaskEnvironment::MainThreadType::UI);
  std::unique_ptr<base::PowerMonitorSource> power_monitor_source(
      new base::PowerMonitorDeviceSource());
  std::unique_ptr<base::PowerMonitor> power_monitor(
      new base::PowerMonitor(std::move(power_monitor_source)));

  HighResolutionTimerManager manager;
  // Simulate a on-AC power event to get to a known initial state.
  manager.OnPowerStateChange(false);

  // Loop a few times to test power toggling.
  for (int times = 0; times != 3; ++times) {
    // The manager has the high resolution clock enabled now.
    EXPECT_TRUE(manager.hi_res_clock_available());
    // But the Time class has it off, because it hasn't been activated.
    EXPECT_FALSE(base::Time::IsHighResolutionTimerInUse());

    // Activate the high resolution timer.
    base::Time::ActivateHighResolutionTimer(true);
    EXPECT_TRUE(base::Time::IsHighResolutionTimerInUse());

    // Simulate a on-battery power event.
    manager.OnPowerStateChange(true);
    EXPECT_FALSE(manager.hi_res_clock_available());
    EXPECT_FALSE(base::Time::IsHighResolutionTimerInUse());

    // Back to on-AC power.
    manager.OnPowerStateChange(false);
    EXPECT_TRUE(manager.hi_res_clock_available());
    EXPECT_TRUE(base::Time::IsHighResolutionTimerInUse());

    // De-activate the high resolution timer.
    base::Time::ActivateHighResolutionTimer(false);
  }
}
#endif  // defined(OS_WIN)

}  // namespace base