Run the later parts of startup as UI thread tasks

content/browser/startup_task_runner_unittest.cc

+// Copyright (c) 2013 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/startup_task_runner.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/run_loop.h"
+#include "base/task_runner.h"
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+namespace {
+
+using base::Closure;
+using testing::_;
+using testing::Assign;
+using testing::Invoke;
+using testing::WithArg;
+
+bool observer_called = false;
+int observer_result;
+base::Closure task;
+
+// I couldn't get gMock's SaveArg to compile, hence had to save the argument
+// this way
+bool SaveTaskArg(const Closure& arg) {
+  task = arg;
+  return true;
+}
+
+void Observer(int result) {
+  observer_called = true;
+  observer_result = result;
+}
+
+class StartupTaskRunnerTest : public testing::Test {
+ public:
+
+  virtual void SetUp() {
+    last_task_ = 0;
+    observer_called = false;
+  }
+
+  int Task1() {
+    last_task_ = 1;
+    return 0;
+  }
+
+  int Task2() {
+    last_task_ = 2;
+    return 0;
+  }
+
+  int FailingTask() {
+    // Task returning failure
+    last_task_ = 3;
+    return 1;
+  }
+
+  int GetLastTask() { return last_task_; }
+
+ private:
+
+  int last_task_;
+};
+
+// We can't use the real message loop, even if we want to, since doing so on
+// Android requires a complex Java infrastructure. The test would have to built
+// as a content_shell test; but content_shell startup invokes the class we are
+// trying to test.
+//
+// The mocks are not directly in TaskRunnerProxy because reference counted
+// objects seem to confuse the mocking framework
+
+class MockTaskRunner {
+ public:
+  MOCK_METHOD3(
+      PostDelayedTask,
+      bool(const tracked_objects::Location&, const Closure&, base::TimeDelta));
+  MOCK_METHOD3(
+      PostNonNestableDelayedTask,
+      bool(const tracked_objects::Location&, const Closure&, base::TimeDelta));
+};
+
+class TaskRunnerProxy : public base::SingleThreadTaskRunner {
+ public:
+  TaskRunnerProxy(MockTaskRunner* mock) : mock_(mock) {}
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE { return true; }
+  virtual bool PostDelayedTask(const tracked_objects::Location& location,
+                               const Closure& closure,
+                               base::TimeDelta delta) OVERRIDE {
+    return mock_->PostDelayedTask(location, closure, delta);
+  }
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& location,
+      const Closure& closure,
+      base::TimeDelta delta) OVERRIDE {
+    return mock_->PostNonNestableDelayedTask(location, closure, delta);
+  }
+
+ private:
+  MockTaskRunner* mock_;
+  virtual ~TaskRunnerProxy() {}
+};
+
+TEST_F(StartupTaskRunnerTest, SynchronousExecution) {
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(mock_runner, PostNonNestableDelayedTask(_, _, _)).Times(0);
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(false, Observer, proxy);
+
+  StartupTask task1 =
+      base::Bind(&StartupTaskRunnerTest::Task1, base::Unretained(this));
+  runner->AddTask(task1);
+  EXPECT_EQ(GetLastTask(), 0);
+  StartupTask task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // On an immediate StartupTaskRunner the tasks should now all have run.
+  EXPECT_EQ(GetLastTask(), 2);
+
+  EXPECT_TRUE(observer_called);
+  EXPECT_EQ(observer_result, 0);
+}
+
+TEST_F(StartupTaskRunnerTest, SynchronousExecutionFailedTask) {
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(mock_runner, PostNonNestableDelayedTask(_, _, _)).Times(0);
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(false, Observer, proxy);
+
+  StartupTask task3 =
+      base::Bind(&StartupTaskRunnerTest::FailingTask, base::Unretained(this));
+  runner->AddTask(task3);
+  EXPECT_EQ(GetLastTask(), 0);
+  StartupTask task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // Only the first task should have run, since it failed
+  EXPECT_EQ(GetLastTask(), 3);
+
+  EXPECT_TRUE(observer_called);
+  EXPECT_EQ(observer_result, 1);
+}
+
+TEST_F(StartupTaskRunnerTest, AsynchronousExecution) {
+
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(
+      mock_runner,
+      PostNonNestableDelayedTask(_, _, base::TimeDelta::FromMilliseconds(0)))
+      .Times(testing::Between(2, 3))
+      .WillRepeatedly(WithArg<1>(Invoke(SaveTaskArg)));
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(true, Observer, proxy);
+
+  StartupTask task1 =
+      base::Bind(&StartupTaskRunnerTest::Task1, base::Unretained(this));
+  runner->AddTask(task1);
+  StartupTask task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // No tasks should have run yet, since we the message loop hasn't run.
+  EXPECT_EQ(GetLastTask(), 0);
+
+  // Fake the actual message loop. Each time a task is run a new task should
+  // be added to the queue, hence updating "task". The loop should actually run
+  // at most 3 times (once for each task plus possibly once for the observer),
+  // the "4" is a backstop.
+  for (int i = 0; i < 4 && !observer_called; i++) {
+    task.Run();
+    EXPECT_EQ(i + 1, GetLastTask());
+  }
+  EXPECT_TRUE(observer_called);
+  EXPECT_EQ(observer_result, 0);
+}
+
+TEST_F(StartupTaskRunnerTest, AsynchronousExecutionFailedTask) {
+
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(
+      mock_runner,
+      PostNonNestableDelayedTask(_, _, base::TimeDelta::FromMilliseconds(0)))
+      .Times(testing::Between(1, 2))
+      .WillRepeatedly(WithArg<1>(Invoke(SaveTaskArg)));
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(true, Observer, proxy);
+
+  StartupTask task3 =
+      base::Bind(&StartupTaskRunnerTest::FailingTask, base::Unretained(this));
+  runner->AddTask(task3);
+  StartupTask task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // No tasks should have run yet, since we the message loop hasn't run.
+  EXPECT_EQ(GetLastTask(), 0);
+
+  // Fake the actual message loop. Each time a task is run a new task should
+  // be added to the queue, hence updating "task". The loop should actually run
+  // at most twice (once for the failed task plus possibly once for the
+  // observer), the "4" is a backstop.
+  for (int i = 0; i < 4 && !observer_called; i++) {
+    task.Run();
+  }
+  EXPECT_EQ(GetLastTask(), 3);
+
+  EXPECT_TRUE(observer_called);
+  EXPECT_EQ(observer_result, 1);
+}
+}  // namespace
+}  // namespace content