SystemMonitor refactoring: move power state monitor into a separate class called PowerMonitor

base/power_monitor/power_monitor_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/power_monitor/power_monitor.h"
+
+#include "base/message_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+class PowerTest : public PowerObserver {
+ public:
+  PowerTest()
+      : power_state_changes_(0),
+        suspends_(0),
+        resumes_(0) {
+  }
+
+  // PowerObserver callbacks.
+  virtual void OnPowerStateChange(bool on_battery_power) OVERRIDE {
+    power_state_changes_++;
+  }
+
+  virtual void OnSuspend() OVERRIDE {
+    suspends_++;
+  }
+
+  virtual void OnResume() OVERRIDE {
+    resumes_++;
+  }
+
+  // Test status counts.
+  int power_state_changes() { return power_state_changes_; }
+  int suspends() { return suspends_; }
+  int resumes() { return resumes_; }
+
+ private:
+  int power_state_changes_;  // Count of OnPowerStateChange notifications.
+  int suspends_;  // Count of OnSuspend notifications.
+  int resumes_;  // Count of OnResume notifications.
+};
+
+class PowerMonitorTest : public testing::Test {
+ protected:
+  PowerMonitorTest() {
+#if defined(OS_MACOSX)
+    // This needs to happen before PowerMonitor's ctor.
+    PowerMonitor::AllocateSystemIOPorts();
+#endif
+    power_monitor_.reset(new PowerMonitor);
+  }
+  virtual ~PowerMonitorTest() {}
+
+  void ProcessPowerEvent(PowerMonitor::PowerEvent event) {
+    power_monitor_->ProcessPowerEvent(event);
+  }
+
+  MessageLoop message_loop_;
+  scoped_ptr<PowerMonitor> power_monitor_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerMonitorTest);
+};
+
+TEST_F(PowerMonitorTest, PowerNotifications) {
+  const int kObservers = 5;
+
+  PowerTest test[kObservers];
+  for (int index = 0; index < kObservers; ++index)
+    power_monitor_->AddObserver(&test[index]);
+
+  // Send a bunch of power changes.  Since the battery power hasn't
+  // actually changed, we shouldn't get notifications.
+  for (int index = 0; index < 5; index++) {
+    ProcessPowerEvent(PowerMonitor::POWER_STATE_EVENT);
+    EXPECT_EQ(test[0].power_state_changes(), 0);
+  }
+
+  // Sending resume when not suspended should have no effect.
+  ProcessPowerEvent(PowerMonitor::RESUME_EVENT);
+  message_loop_.RunAllPending();
+  EXPECT_EQ(test[0].resumes(), 0);
+
+  // Pretend we suspended.
+  ProcessPowerEvent(PowerMonitor::SUSPEND_EVENT);
+  message_loop_.RunAllPending();
+  EXPECT_EQ(test[0].suspends(), 1);
+
+  // Send a second suspend notification.  This should be suppressed.
+  ProcessPowerEvent(PowerMonitor::SUSPEND_EVENT);
+  message_loop_.RunAllPending();
+  EXPECT_EQ(test[0].suspends(), 1);
+
+  // Pretend we were awakened.
+  ProcessPowerEvent(PowerMonitor::RESUME_EVENT);
+  message_loop_.RunAllPending();
+  EXPECT_EQ(test[0].resumes(), 1);
+
+  // Send a duplicate resume notification.  This should be suppressed.
+  ProcessPowerEvent(PowerMonitor::RESUME_EVENT);
+  message_loop_.RunAllPending();
+  EXPECT_EQ(test[0].resumes(), 1);
+}
+
+}  // namespace base