[chromeos] Limit the data samples stored by PowerDataCollector.

chromeos/power/power_data_collector_unittest.cc

Index: chromeos/power/power_data_collector_unittest.cc
diff --git a/chromeos/power/power_data_collector_unittest.cc b/chromeos/power/power_data_collector_unittest.cc
index a04a4d894595855868e764315c7bc2051a799005..e2bed836b02b3570c4e8fca09a433642d066e7f0 100644
--- a/chromeos/power/power_data_collector_unittest.cc
+++ b/chromeos/power/power_data_collector_unittest.cc
@@ -38,23 +38,39 @@ TEST_F(PowerDataCollectorTest, PowerChanged) {
 
   prop1.set_external_power(power_manager::PowerSupplyProperties::DISCONNECTED);
   prop1.set_battery_percent(20.00);
-
   power_data_collector_->PowerChanged(prop1);
-  const std::vector<PowerDataCollector::PowerSupplySnapshot>& data1 =
+  const std::list<PowerDataCollector::PowerSupplySnapshot>& data1 =
       power_data_collector_->power_supply_data();
   ASSERT_EQ(static_cast<size_t>(1), data1.size());
-  EXPECT_DOUBLE_EQ(prop1.battery_percent(), data1[0].battery_percent);
-  EXPECT_FALSE(data1[0].external_power);
+  EXPECT_DOUBLE_EQ(prop1.battery_percent(), data1.front().battery_percent);
+  EXPECT_FALSE(data1.front().external_power);
 
   prop2.set_external_power(power_manager::PowerSupplyProperties::AC);
   prop2.set_battery_percent(100.00);
-
   power_data_collector_->PowerChanged(prop2);
-  const std::vector<PowerDataCollector::PowerSupplySnapshot>& data2 =
+  const std::list<PowerDataCollector::PowerSupplySnapshot>& data2 =
       power_data_collector_->power_supply_data();
   ASSERT_EQ(static_cast<size_t>(2), data2.size());
-  EXPECT_DOUBLE_EQ(prop2.battery_percent(), data1[1].battery_percent);
-  EXPECT_TRUE(data2[1].external_power);
+  EXPECT_DOUBLE_EQ(prop2.battery_percent(), data2.back().battery_percent);
+  EXPECT_TRUE(data2.back().external_power);
+}
+
+TEST_F(PowerDataCollectorTest, AddSnapshot) {
+  PowerDataCollector::PowerSupplySnapshot snapshot1, snapshot2;
+
+  snapshot1.time = base::TimeTicks::Now();
+  snapshot2.time = base::TimeTicks::Now() + base::TimeDelta::FromSeconds(
+      PowerDataCollector::kSampleCountTimeLimitSec);
+
+  power_data_collector_->AddSnapshot(snapshot1);
+  const std::list<PowerDataCollector::PowerSupplySnapshot>& data1 =
+      power_data_collector_->power_supply_data();
+  ASSERT_EQ(static_cast<size_t>(1), data1.size());
+
+  power_data_collector_->AddSnapshot(snapshot2);
+  const std::list<PowerDataCollector::PowerSupplySnapshot>& data2 =
+      power_data_collector_->power_supply_data();
+  ASSERT_EQ(static_cast<size_t>(1), data2.size());
 }
 
 }  // namespace chromeos