[DeviceService] Replace content browser test with service test for BatteryMonitorImpl

services/device/battery/battery_monitor_impl_unittest.cc

Index: services/device/battery/battery_monitor_impl_unittest.cc
diff --git a/services/device/battery/battery_monitor_impl_unittest.cc b/services/device/battery/battery_monitor_impl_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..86d5ac18b084c012a2dfbc85542c4d2771aef182
--- /dev/null
+++ b/services/device/battery/battery_monitor_impl_unittest.cc
@@ -0,0 +1,192 @@
+// Copyright (c) 2017 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 "device/battery/battery_monitor_impl.h"
+
+#include <utility>
+
+#include "base/macros.h"
+#include "base/run_loop.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "device/battery/battery_monitor.mojom.h"
+#include "device/battery/battery_status_manager.h"
+#include "device/battery/battery_status_service.h"
+#include "services/device/device_service_test_base.h"
+#include "services/device/public/interfaces/constants.mojom.h"
+
+// These tests run against the implementation of the BatteryMonitor interface
+// inside Device Service, with a dummy BatteryManager set as a source of the
+// battery information. They can be run only on platforms that use the default
+// battery service implementation, ie. on the platforms where
+// BatteryStatusService is used.
+
+namespace device {
+
+namespace {
+
+void ExpectBatteryStatus(bool* out_called,
+                         const mojom::BatteryStatus& expected,
+                         const base::Closure& quit_closure,
+                         mojom::BatteryStatusPtr status) {
+  if (out_called)
+    *out_called = true;
+  EXPECT_EQ(expected.charging, status->charging);
+  EXPECT_EQ(expected.charging_time, status->charging_time);
+  EXPECT_EQ(expected.discharging_time, status->discharging_time);
+  EXPECT_EQ(expected.level, status->level);
+  quit_closure.Run();
+}
+
+class FakeBatteryManager : public BatteryStatusManager {
+ public:
+  explicit FakeBatteryManager(
+      const BatteryStatusService::BatteryUpdateCallback& callback)
+      : callback_(callback), battery_status_available_(true), started_(false) {}
+  ~FakeBatteryManager() override {}
+
+  // Methods from BatteryStatusManager.
+  bool StartListeningBatteryChange() override {
+    started_ = true;
+    if (battery_status_available_)
+      InvokeUpdateCallback();
+    return battery_status_available_;
+  }
+
+  void StopListeningBatteryChange() override {}
+
+  void InvokeUpdateCallback() {
+    // Invoke asynchronously to mimic the OS-specific battery managers.
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(callback_, status_));
+  }
+
+  void set_battery_status(const mojom::BatteryStatus& status) {
+    status_ = status;
+  }
+
+  void set_battery_status_available(bool value) {
+    battery_status_available_ = value;
+  }
+
+  bool started() { return started_; }
+
+ private:
+  BatteryStatusService::BatteryUpdateCallback callback_;
+  bool battery_status_available_;
+  bool started_;
+  mojom::BatteryStatus status_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeBatteryManager);
+};
+
+class BatteryMonitorImplTest : public DeviceServiceTestBase {
+ public:
+  BatteryMonitorImplTest() = default;
+  ~BatteryMonitorImplTest() override = default;
+
+ protected:
+  void SetUp() override {
+    DeviceServiceTestBase::SetUp();
+
+    BatteryStatusService* battery_service = BatteryStatusService::GetInstance();
+    std::unique_ptr<FakeBatteryManager> battery_manager(
+        new FakeBatteryManager(battery_service->GetUpdateCallbackForTesting()));
+    battery_manager_ = battery_manager.get();
+    battery_service->SetBatteryManagerForTesting(std::move(battery_manager));
+
+    connector()->BindInterface(mojom::kServiceName, &battery_monitor_);
+  }
+
+  void TearDown() override {
+    battery_monitor_.reset();
+    // Enforce BatteryMonitorImpl destruction to run before Device Service
+    // destruction shutting down battery status service, thus the
+    // BatteryMonitorImpl instance can detach from battery status service
+    // completely.
+    base::RunLoop().RunUntilIdle();
+  }
+
+  FakeBatteryManager* battery_manager() { return battery_manager_; }
+
+  mojom::BatteryMonitorPtr battery_monitor_;
+
+ private:
+  FakeBatteryManager* battery_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(BatteryMonitorImplTest);
+};
+
+TEST_F(BatteryMonitorImplTest, BatteryManagerDefaultValues) {
+  // Set the fake battery manager to return false on start. Verify that the
+  // default battery values will be returned to consumers of Device Service.
+  battery_manager()->set_battery_status_available(false);
+
+  mojom::BatteryStatus default_status;
+  default_status.charging = true;
+  default_status.charging_time = 0;
+  default_status.discharging_time = std::numeric_limits<double>::infinity();
+  default_status.level = 1.0;
+  base::RunLoop run_loop;
+  battery_monitor_->QueryNextStatus(base::Bind(
+      &ExpectBatteryStatus, nullptr, default_status, run_loop.QuitClosure()));
+  run_loop.Run();
+  EXPECT_TRUE(battery_manager()->started());
+}
+
+TEST_F(BatteryMonitorImplTest, BatteryManagerPredefinedValues) {
+  // Set the fake battery manager to return predefined battery status values.
+  // Verify that the predefined values will be returned to consumers of Device
+  // Service.
+  mojom::BatteryStatus status;
+  status.charging = true;
+  status.charging_time = 100;
+  status.discharging_time = std::numeric_limits<double>::infinity();
+  status.level = 0.5;
+  battery_manager()->set_battery_status(status);
+
+  base::RunLoop run_loop;
+  battery_monitor_->QueryNextStatus(base::Bind(&ExpectBatteryStatus, nullptr,
+                                               status, run_loop.QuitClosure()));
+  run_loop.Run();
+  EXPECT_TRUE(battery_manager()->started());
+}
+
+TEST_F(BatteryMonitorImplTest, BatteryManagerInvokeUpdate) {
+  // Set the fake battery manager to return predefined battery status values,
+  // after queried the battery status first time, query again, the second time
+  // query will be pending, and then we change battery level to 0.6 and invoke
+  // update. Verify that the second query will get the new level 0.6 correctly.
+  mojom::BatteryStatus status;
+  status.charging = true;
+  status.charging_time = 100;
+  status.discharging_time = std::numeric_limits<double>::infinity();
+  status.level = 0.5;
+  battery_manager()->set_battery_status(status);
+
+  // The first time query should succeed.
+  base::RunLoop run_loop1;
+  battery_monitor_->QueryNextStatus(base::Bind(
+      &ExpectBatteryStatus, nullptr, status, run_loop1.QuitClosure()));
+  run_loop1.Run();
+  EXPECT_TRUE(battery_manager()->started());
+
+  // The second time query should be pending.
+  bool called = false;
+  status.level = 0.6;
+  base::RunLoop run_loop2;
+  battery_monitor_->QueryNextStatus(base::Bind(
+      &ExpectBatteryStatus, &called, status, run_loop2.QuitClosure()));
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(called);
+
+  // InvokeUpdateCallback should fire the pending query correctly.
+  battery_manager()->set_battery_status(status);
+  battery_manager()->InvokeUpdateCallback();
+  run_loop2.Run();
+  EXPECT_TRUE(called);
+}
+
+}  // namespace
+
+}  // namespace device