Battery impact UMA

content/browser/power_usage_monitor_impl_unittest.cc

+// Copyright 2014 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 "content/browser/power_usage_monitor_impl.h"
+
+#include "content/public/browser/notification_types.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+
+// Dummy ID to identify a phantom RenderProcessHost in tests.
+const int kDummyRenderProcessHostID = 1;
+
+class SystemInterfaceForTest : public PowerUsageMonitor::SystemInterface {
+ public:
+  SystemInterfaceForTest()
+      : num_pending_histogram_reports_(0),
+        discharge_percent_per_hour_(0),
+        now_(base::Time::FromInternalValue(1000)) {}
+  ~SystemInterfaceForTest() override {}
+
+  int num_pending_histogram_reports() const {
+    return num_pending_histogram_reports_;
+  }
+
+  int discharge_percent_per_hour() const {
+    return discharge_percent_per_hour_;
+  }
+
+  void AdvanceClockSeconds(int seconds) {
+    now_ += base::TimeDelta::FromSeconds(seconds);
+  }
+
+  void AdvanceClockMinutes(int minutes) {
+    now_ += base::TimeDelta::FromMinutes(minutes);
+  }
+
+  void ScheduleHistogramReport(base::TimeDelta delay) override {
+    num_pending_histogram_reports_++;
+  }
+
+  void CancelPendingHistogramReports() override {
+    num_pending_histogram_reports_ = 0;
+  }
+
+  void RecordDischargePercentPerHour(int percent_per_hour) override {
+    discharge_percent_per_hour_ = percent_per_hour;
+  }
+
+  base::Time Now() override { return now_; }
+
+ private:
+  int num_pending_histogram_reports_;
+  int discharge_percent_per_hour_;
+  base::Time now_;
+};
+
+class PowerUsageMonitorTest : public testing::Test {
+ protected:
+  virtual void SetUp() {
+    monitor_.reset(new PowerUsageMonitor);
+    // PowerUsageMonitor assumes ownership.
+    scoped_ptr<SystemInterfaceForTest> test_interface(
+        new SystemInterfaceForTest());
+    system_interface_ = test_interface.get();
+    monitor_->SetSystemInterfaceForTest(test_interface.Pass());
+
+    // Without live renderers, the monitor won't do anything.
+    monitor_->OnRenderProcessNotification(NOTIFICATION_RENDERER_PROCESS_CREATED,
+                                          kDummyRenderProcessHostID);
+  }
+
+  void UpdateBatteryStatus(bool charging, double battery_level) {
+    device::BatteryStatus battery_status;

[ppi, 2014/11/16 16:03:08]

nit: include what you use, I think that would be
"device/battery/battery_monitor.mojom.h".

[jeremy, 2014/11/17 07:50:48]

Done.

+    battery_status.charging = charging;
+    battery_status.level = battery_level;
+    monitor_->OnBatteryStatusUpdate(battery_status);
+  }
+
+  void KillTestRenderer() {
+    monitor_->OnRenderProcessNotification(
+        NOTIFICATION_RENDERER_PROCESS_CLOSED, kDummyRenderProcessHostID);
+  }
+
+  scoped_ptr<PowerUsageMonitor> monitor_;
+  SystemInterfaceForTest* system_interface_;
+  TestBrowserThreadBundle thread_bundle_;
+};
+
+TEST_F(PowerUsageMonitorTest, StartStopQuickly) {
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  int initial_num_histogram_reports =
+      system_interface_->num_pending_histogram_reports();
+  ASSERT_GT(initial_num_histogram_reports, 0);
+
+  // Battery level goes down a bit.
+  system_interface_->AdvanceClockSeconds(1);
+  UpdateBatteryStatus(false, 0.9);
+  ASSERT_EQ(initial_num_histogram_reports,
+            system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+
+  // Wall power connected.
+  system_interface_->AdvanceClockSeconds(30);
+  UpdateBatteryStatus(true, 0);
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+}
+
+TEST_F(PowerUsageMonitorTest, DischargePercentReported) {
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  int initial_num_histogram_reports =
+      system_interface_->num_pending_histogram_reports();
+  ASSERT_GT(initial_num_histogram_reports, 0);
+
+  // Battery level goes down a bit.
+  system_interface_->AdvanceClockSeconds(30);
+  UpdateBatteryStatus(false, 0.9);
+  ASSERT_EQ(initial_num_histogram_reports,
+            system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+
+  // Wall power connected.
+  system_interface_->AdvanceClockMinutes(31);
+  UpdateBatteryStatus(true, 0);
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+  ASSERT_GT(system_interface_->discharge_percent_per_hour(), 0);
+}
+
+TEST_F(PowerUsageMonitorTest, NoRenderersDisablesMonitoring) {
+  KillTestRenderer();
+
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+
+  // Wall power connected.
+  system_interface_->AdvanceClockSeconds(30);
+  UpdateBatteryStatus(true, 0.5);
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+}
+
+TEST_F(PowerUsageMonitorTest, NoRenderersCancelsInProgressMonitoring) {
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_GT(system_interface_->num_pending_histogram_reports(), 0);
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+
+  // All renderers killed.
+  KillTestRenderer();
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+
+  // Wall power connected.
+  system_interface_->AdvanceClockMinutes(31);
+  UpdateBatteryStatus(true, 0);
+  ASSERT_EQ(0, system_interface_->num_pending_histogram_reports());
+  ASSERT_EQ(0, system_interface_->discharge_percent_per_hour());
+}
+
+}  // namespace content