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/test/test_browser_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+
+class SystemInterfaceForTest : public PowerUsageMonitor::SystemInterface {
+ public:
+  SystemInterfaceForTest()
+      : num_pending_histogram_reports_(0), now_(base::Time::Now()) {}
+  virtual ~SystemInterfaceForTest() {}
+
+  int num_pending_histogram_reports() { return num_pending_histogram_reports_; }
+
+  void AdvanceClockSeconds(int seconds) {
+    now_ += base::TimeDelta::FromSeconds(seconds);
+  }
+
+  void AdvanceClockHours(int hours) {
+    now_ += base::TimeDelta::FromHours(hours);
+  }
+
+  virtual void ScheduleHistogramReport(base::TimeDelta delay) override {
+    num_pending_histogram_reports_++;
+  }
+
+  virtual void CancelPendingHistogramReports() override {
+    num_pending_histogram_reports_ = 0;
+  }
+
+  virtual base::Time Now() override { return now_; }
+
+ protected:
+  virtual void ReportBatteryLevelHistogram(
+      base::Time start_time,
+      base::TimeDelta discharge_time) override {}
+
+ private:
+  int num_pending_histogram_reports_;
+  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_->SetNumLiveRenderersForTest(1);
+  }
+
+  void UpdateBatteryStatus(bool charging, double battery_level) {
+    blink::WebBatteryStatus battery_status;
+    battery_status.charging = charging;
+    battery_status.level = battery_level;
+    monitor_->OnBatteryStatusUpdate(battery_status);
+  }
+
+  scoped_ptr<PowerUsageMonitor> monitor_;
+  SystemInterfaceForTest* system_interface_;
+  TestBrowserThreadBundle thread_bundle_;
+};
+
+TEST_F(PowerUsageMonitorTest, StartStop) {
+  // 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());
+
+  // Wall power connected.
+  system_interface_->AdvanceClockSeconds(30);
+  UpdateBatteryStatus(true, 0.5);
+  ASSERT_EQ(system_interface_->num_pending_histogram_reports(), 0);
+}
+
+TEST_F(PowerUsageMonitorTest, NoRenderersDisablesMonitoring) {
+  monitor_->SetNumLiveRenderersForTest(0);
+
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_EQ(system_interface_->num_pending_histogram_reports(), 0);
+
+  // Wall power connected.
+  system_interface_->AdvanceClockSeconds(30);
+  UpdateBatteryStatus(true, 0.5);
+  ASSERT_EQ(system_interface_->num_pending_histogram_reports(), 0);
+}
+
+TEST_F(PowerUsageMonitorTest, ReportOnceEvery24Hours) {
+  // Going on battery power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_GT(system_interface_->num_pending_histogram_reports(), 0);
+
+  // Tell the monitor that a histogram was recorded.
+  monitor_->BatteryLevelReported();
+
+  // Connect back to wall power.
+  system_interface_->AdvanceClockHours(1);
+  UpdateBatteryStatus(true, 0.9);
+
+  // Disconnect from Wall power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_EQ(system_interface_->num_pending_histogram_reports(), 0);
+
+  // Back on wall power.
+  UpdateBatteryStatus(true, 0.9);
+
+  // 24 hours later.
+  system_interface_->AdvanceClockHours(24);
+
+  // Disconnect from Wall power.
+  UpdateBatteryStatus(false, 1.0);
+  ASSERT_GT(system_interface_->num_pending_histogram_reports(), 0);
+}
+
+}  // namespace content