base/test/sequenced_task_runner_test_template.h - gn - Git at Google

 // 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.

 // SequencedTaskRunnerTest defines tests that implementations of
 // SequencedTaskRunner should pass in order to be conformant.
 // See task_runner_test_template.h for a description of how to use the
 // constructs in this file; these work the same.

 #ifndef BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_
 #define BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_

 #include <cstddef>
 #include <iosfwd>
 #include <vector>

 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"

 namespace base {

 namespace internal {

 struct TaskEvent {
   enum Type { POST, START, END };
   TaskEvent(int i, Type type);
   int i;
   Type type;
 };

 // Utility class used in the tests below.
 class SequencedTaskTracker : public RefCountedThreadSafe<SequencedTaskTracker> {
  public:
   SequencedTaskTracker();

   // Posts the non-nestable task |task|, and records its post event.
   void PostWrappedNonNestableTask(SequencedTaskRunner* task_runner,
                                   const Closure& task);

   // Posts the nestable task |task|, and records its post event.
   void PostWrappedNestableTask(SequencedTaskRunner* task_runner,
                                const Closure& task);

   // Posts the delayed non-nestable task |task|, and records its post event.
   void PostWrappedDelayedNonNestableTask(SequencedTaskRunner* task_runner,
                                          const Closure& task,
                                          TimeDelta delay);

   // Posts |task_count| non-nestable tasks.
   void PostNonNestableTasks(SequencedTaskRunner* task_runner, int task_count);

   const std::vector<TaskEvent>& GetTaskEvents() const;

   // Returns after the tracker observes a total of |count| task completions.
   void WaitForCompletedTasks(int count);

  private:
   friend class RefCountedThreadSafe<SequencedTaskTracker>;

   ~SequencedTaskTracker();

   // A task which runs |task|, recording the start and end events.
   void RunTask(const Closure& task, int task_i);

   // Records a post event for task |i|. The owner is expected to be holding
   // |lock_| (unlike |TaskStarted| and |TaskEnded|).
   void TaskPosted(int i);

   // Records a start event for task |i|.
   void TaskStarted(int i);

   // Records a end event for task |i|.
   void TaskEnded(int i);

   // Protects events_, next_post_i_, task_end_count_ and task_end_cv_.
   Lock lock_;

   // The events as they occurred for each task (protected by lock_).
   std::vector<TaskEvent> events_;

   // The ordinal to be used for the next task-posting task (protected by
   // lock_).
   int next_post_i_;

   // The number of task end events we've received.
   int task_end_count_;
   ConditionVariable task_end_cv_;

   DISALLOW_COPY_AND_ASSIGN(SequencedTaskTracker);
 };

 void PrintTo(const TaskEvent& event, std::ostream* os);

 // Checks the non-nestable task invariants for all tasks in |events|.
 //
 // The invariants are:
 // 1) Events started and ended in the same order that they were posted.
 // 2) Events for an individual tasks occur in the order {POST, START, END},
 //    and there is only one instance of each event type for a task.
 // 3) The only events between a task's START and END events are the POSTs of
 //    other tasks. I.e. tasks were run sequentially, not interleaved.
 ::testing::AssertionResult CheckNonNestableInvariants(
     const std::vector<TaskEvent>& events,
     int task_count);

 }  // namespace internal

 template <typename TaskRunnerTestDelegate>
 class SequencedTaskRunnerTest : public testing::Test {
  protected:
   SequencedTaskRunnerTest()
       : task_tracker_(new internal::SequencedTaskTracker()) {}

   const scoped_refptr<internal::SequencedTaskTracker> task_tracker_;
   TaskRunnerTestDelegate delegate_;
 };

 TYPED_TEST_CASE_P(SequencedTaskRunnerTest);

 // This test posts N non-nestable tasks in sequence, and expects them to run
 // in FIFO order, with no part of any two tasks' execution
 // overlapping. I.e. that each task starts only after the previously-posted
 // one has finished.
 TYPED_TEST_P(SequencedTaskRunnerTest, SequentialNonNestable) {
   const int kTaskCount = 1000;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   this->task_tracker_->PostWrappedNonNestableTask(
       task_runner.get(),
       Bind(&PlatformThread::Sleep, TimeDelta::FromSeconds(1)));
   for (int i = 1; i < kTaskCount; ++i) {
     this->task_tracker_->PostWrappedNonNestableTask(task_runner.get(),
                                                     Closure());
   }

   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }

 // This test posts N nestable tasks in sequence. It has the same expectations
 // as SequentialNonNestable because even though the tasks are nestable, they
 // will not be run nestedly in this case.
 TYPED_TEST_P(SequencedTaskRunnerTest, SequentialNestable) {
   const int kTaskCount = 1000;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   this->task_tracker_->PostWrappedNestableTask(
       task_runner.get(),
       Bind(&PlatformThread::Sleep, TimeDelta::FromSeconds(1)));
   for (int i = 1; i < kTaskCount; ++i) {
     this->task_tracker_->PostWrappedNestableTask(task_runner.get(), Closure());
   }

   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }

 // This test posts non-nestable tasks in order of increasing delay, and checks
 // that that the tasks are run in FIFO order and that there is no execution
 // overlap whatsoever between any two tasks.
 TYPED_TEST_P(SequencedTaskRunnerTest, SequentialDelayedNonNestable) {
   const int kTaskCount = 20;
   const int kDelayIncrementMs = 50;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   for (int i = 0; i < kTaskCount; ++i) {
     this->task_tracker_->PostWrappedDelayedNonNestableTask(
         task_runner.get(), Closure(),
         TimeDelta::FromMilliseconds(kDelayIncrementMs * i));
   }

   this->task_tracker_->WaitForCompletedTasks(kTaskCount);
   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }

 // This test posts a fast, non-nestable task from within each of a number of
 // slow, non-nestable tasks and checks that they all run in the sequence they
 // were posted in and that there is no execution overlap whatsoever.
 TYPED_TEST_P(SequencedTaskRunnerTest, NonNestablePostFromNonNestableTask) {
   const int kParentCount = 10;
   const int kChildrenPerParent = 10;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   for (int i = 0; i < kParentCount; ++i) {
     Closure task = Bind(
         &internal::SequencedTaskTracker::PostNonNestableTasks,
         this->task_tracker_,
         RetainedRef(task_runner),
         kChildrenPerParent);
     this->task_tracker_->PostWrappedNonNestableTask(task_runner.get(), task);
   }

   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(
       this->task_tracker_->GetTaskEvents(),
       kParentCount * (kChildrenPerParent + 1)));
 }

 // This test posts two tasks with the same delay, and checks that the tasks are
 // run in the order in which they were posted.
 //
 // NOTE: This is actually an approximate test since the API only takes a
 // "delay" parameter, so we are not exactly simulating two tasks that get
 // posted at the exact same time. It would be nice if the API allowed us to
 // specify the desired run time.
 TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTasksSameDelay) {
   const int kTaskCount = 2;
   const TimeDelta kDelay = TimeDelta::FromMilliseconds(100);

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
                                                          Closure(), kDelay);
   this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
                                                          Closure(), kDelay);
   this->task_tracker_->WaitForCompletedTasks(kTaskCount);
   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }

 // This test posts a normal task and a delayed task, and checks that the
 // delayed task runs after the normal task even if the normal task takes
 // a long time to run.
 TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTaskAfterLongTask) {
   const int kTaskCount = 2;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   this->task_tracker_->PostWrappedNonNestableTask(
       task_runner.get(),
       base::Bind(&PlatformThread::Sleep, TimeDelta::FromMilliseconds(50)));
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner.get(), Closure(), TimeDelta::FromMilliseconds(10));
   this->task_tracker_->WaitForCompletedTasks(kTaskCount);
   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }

 // Test that a pile of normal tasks and a delayed task run in the
 // time-to-run order.
 TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTaskAfterManyLongTasks) {
   const int kTaskCount = 11;

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   for (int i = 0; i < kTaskCount - 1; i++) {
     this->task_tracker_->PostWrappedNonNestableTask(
         task_runner.get(),
         base::Bind(&PlatformThread::Sleep, TimeDelta::FromMilliseconds(50)));
   }
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner.get(), Closure(), TimeDelta::FromMilliseconds(10));
   this->task_tracker_->WaitForCompletedTasks(kTaskCount);
   this->delegate_.StopTaskRunner();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
 }


 // TODO(francoisk777@gmail.com) Add a test, similiar to the above, which runs
 // some tasked nestedly (which should be implemented in the test
 // delegate). Also add, to the the test delegate, a predicate which checks
 // whether the implementation supports nested tasks.
 //

 // The SequencedTaskRunnerTest test case verifies behaviour that is expected
 // from a sequenced task runner in order to be conformant.
 REGISTER_TYPED_TEST_CASE_P(SequencedTaskRunnerTest,
                            SequentialNonNestable,
                            SequentialNestable,
                            SequentialDelayedNonNestable,
                            NonNestablePostFromNonNestableTask,
                            DelayedTasksSameDelay,
                            DelayedTaskAfterLongTask,
                            DelayedTaskAfterManyLongTasks);

 template <typename TaskRunnerTestDelegate>
 class SequencedTaskRunnerDelayedTest
     : public SequencedTaskRunnerTest<TaskRunnerTestDelegate> {};

 TYPED_TEST_CASE_P(SequencedTaskRunnerDelayedTest);

 // This test posts a delayed task, and checks that the task is run later than
 // the specified time.
 TYPED_TEST_P(SequencedTaskRunnerDelayedTest, DelayedTaskBasic) {
   const int kTaskCount = 1;
   const TimeDelta kDelay = TimeDelta::FromMilliseconds(100);

   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();

   Time time_before_run = Time::Now();
   this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
                                                          Closure(), kDelay);
   this->task_tracker_->WaitForCompletedTasks(kTaskCount);
   this->delegate_.StopTaskRunner();
   Time time_after_run = Time::Now();

   EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
                                          kTaskCount));
   EXPECT_LE(kDelay, time_after_run - time_before_run);
 }

 // SequencedTaskRunnerDelayedTest tests that the |delay| parameter of
 // is used to actually wait for |delay| ms before executing the task.
 // This is not mandatory for a SequencedTaskRunner to be compliant.
 REGISTER_TYPED_TEST_CASE_P(SequencedTaskRunnerDelayedTest, DelayedTaskBasic);

 }  // namespace base

 #endif  // BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_
	// 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.

	// SequencedTaskRunnerTest defines tests that implementations of
	// SequencedTaskRunner should pass in order to be conformant.
	// See task_runner_test_template.h for a description of how to use the
	// constructs in this file; these work the same.

	#ifndef BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_
	#define BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_

	#include <cstddef>
	#include <iosfwd>
	#include <vector>

	#include "base/bind.h"
	#include "base/callback.h"
	#include "base/macros.h"
	#include "base/memory/ref_counted.h"
	#include "base/sequenced_task_runner.h"
	#include "base/synchronization/condition_variable.h"
	#include "base/synchronization/lock.h"
	#include "base/time/time.h"
	#include "testing/gtest/include/gtest/gtest.h"

	namespace base {

	namespace internal {

	struct TaskEvent {
	enum Type { POST, START, END };
	TaskEvent(int i, Type type);
	int i;
	Type type;
	};

	// Utility class used in the tests below.
	class SequencedTaskTracker : public RefCountedThreadSafe<SequencedTaskTracker> {
	public:
	SequencedTaskTracker();

	// Posts the non-nestable task \|task\|, and records its post event.
	void PostWrappedNonNestableTask(SequencedTaskRunner* task_runner,
	const Closure& task);

	// Posts the nestable task \|task\|, and records its post event.
	void PostWrappedNestableTask(SequencedTaskRunner* task_runner,
	const Closure& task);

	// Posts the delayed non-nestable task \|task\|, and records its post event.
	void PostWrappedDelayedNonNestableTask(SequencedTaskRunner* task_runner,
	const Closure& task,
	TimeDelta delay);

	// Posts \|task_count\| non-nestable tasks.
	void PostNonNestableTasks(SequencedTaskRunner* task_runner, int task_count);

	const std::vector<TaskEvent>& GetTaskEvents() const;

	// Returns after the tracker observes a total of \|count\| task completions.
	void WaitForCompletedTasks(int count);

	private:
	friend class RefCountedThreadSafe<SequencedTaskTracker>;

	~SequencedTaskTracker();

	// A task which runs \|task\|, recording the start and end events.
	void RunTask(const Closure& task, int task_i);

	// Records a post event for task \|i\|. The owner is expected to be holding
	// \|lock_\| (unlike \|TaskStarted\| and \|TaskEnded\|).
	void TaskPosted(int i);

	// Records a start event for task \|i\|.
	void TaskStarted(int i);

	// Records a end event for task \|i\|.
	void TaskEnded(int i);

	// Protects events_, next_post_i_, task_end_count_ and task_end_cv_.
	Lock lock_;

	// The events as they occurred for each task (protected by lock_).
	std::vector<TaskEvent> events_;

	// The ordinal to be used for the next task-posting task (protected by
	// lock_).
	int next_post_i_;

	// The number of task end events we've received.
	int task_end_count_;
	ConditionVariable task_end_cv_;

	DISALLOW_COPY_AND_ASSIGN(SequencedTaskTracker);
	};

	void PrintTo(const TaskEvent& event, std::ostream* os);

	// Checks the non-nestable task invariants for all tasks in \|events\|.
	//
	// The invariants are:
	// 1) Events started and ended in the same order that they were posted.
	// 2) Events for an individual tasks occur in the order {POST, START, END},
	// and there is only one instance of each event type for a task.
	// 3) The only events between a task's START and END events are the POSTs of
	// other tasks. I.e. tasks were run sequentially, not interleaved.
	::testing::AssertionResult CheckNonNestableInvariants(
	const std::vector<TaskEvent>& events,
	int task_count);

	} // namespace internal

	template <typename TaskRunnerTestDelegate>
	class SequencedTaskRunnerTest : public testing::Test {
	protected:
	SequencedTaskRunnerTest()
	: task_tracker_(new internal::SequencedTaskTracker()) {}

	const scoped_refptr<internal::SequencedTaskTracker> task_tracker_;
	TaskRunnerTestDelegate delegate_;
	};

	TYPED_TEST_CASE_P(SequencedTaskRunnerTest);

	// This test posts N non-nestable tasks in sequence, and expects them to run
	// in FIFO order, with no part of any two tasks' execution
	// overlapping. I.e. that each task starts only after the previously-posted
	// one has finished.
	TYPED_TEST_P(SequencedTaskRunnerTest, SequentialNonNestable) {
	const int kTaskCount = 1000;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	this->task_tracker_->PostWrappedNonNestableTask(
	task_runner.get(),
	Bind(&PlatformThread::Sleep, TimeDelta::FromSeconds(1)));
	for (int i = 1; i < kTaskCount; ++i) {
	this->task_tracker_->PostWrappedNonNestableTask(task_runner.get(),
	Closure());
	}

	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}

	// This test posts N nestable tasks in sequence. It has the same expectations
	// as SequentialNonNestable because even though the tasks are nestable, they
	// will not be run nestedly in this case.
	TYPED_TEST_P(SequencedTaskRunnerTest, SequentialNestable) {
	const int kTaskCount = 1000;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	this->task_tracker_->PostWrappedNestableTask(
	task_runner.get(),
	Bind(&PlatformThread::Sleep, TimeDelta::FromSeconds(1)));
	for (int i = 1; i < kTaskCount; ++i) {
	this->task_tracker_->PostWrappedNestableTask(task_runner.get(), Closure());
	}

	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}

	// This test posts non-nestable tasks in order of increasing delay, and checks
	// that that the tasks are run in FIFO order and that there is no execution
	// overlap whatsoever between any two tasks.
	TYPED_TEST_P(SequencedTaskRunnerTest, SequentialDelayedNonNestable) {
	const int kTaskCount = 20;
	const int kDelayIncrementMs = 50;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	for (int i = 0; i < kTaskCount; ++i) {
	this->task_tracker_->PostWrappedDelayedNonNestableTask(
	task_runner.get(), Closure(),
	TimeDelta::FromMilliseconds(kDelayIncrementMs * i));
	}

	this->task_tracker_->WaitForCompletedTasks(kTaskCount);
	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}

	// This test posts a fast, non-nestable task from within each of a number of
	// slow, non-nestable tasks and checks that they all run in the sequence they
	// were posted in and that there is no execution overlap whatsoever.
	TYPED_TEST_P(SequencedTaskRunnerTest, NonNestablePostFromNonNestableTask) {
	const int kParentCount = 10;
	const int kChildrenPerParent = 10;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	for (int i = 0; i < kParentCount; ++i) {
	Closure task = Bind(
	&internal::SequencedTaskTracker::PostNonNestableTasks,
	this->task_tracker_,
	RetainedRef(task_runner),
	kChildrenPerParent);
	this->task_tracker_->PostWrappedNonNestableTask(task_runner.get(), task);
	}

	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(
	this->task_tracker_->GetTaskEvents(),
	kParentCount * (kChildrenPerParent + 1)));
	}

	// This test posts two tasks with the same delay, and checks that the tasks are
	// run in the order in which they were posted.
	//
	// NOTE: This is actually an approximate test since the API only takes a
	// "delay" parameter, so we are not exactly simulating two tasks that get
	// posted at the exact same time. It would be nice if the API allowed us to
	// specify the desired run time.
	TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTasksSameDelay) {
	const int kTaskCount = 2;
	const TimeDelta kDelay = TimeDelta::FromMilliseconds(100);

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
	Closure(), kDelay);
	this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
	Closure(), kDelay);
	this->task_tracker_->WaitForCompletedTasks(kTaskCount);
	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}

	// This test posts a normal task and a delayed task, and checks that the
	// delayed task runs after the normal task even if the normal task takes
	// a long time to run.
	TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTaskAfterLongTask) {
	const int kTaskCount = 2;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	this->task_tracker_->PostWrappedNonNestableTask(
	task_runner.get(),
	base::Bind(&PlatformThread::Sleep, TimeDelta::FromMilliseconds(50)));
	this->task_tracker_->PostWrappedDelayedNonNestableTask(
	task_runner.get(), Closure(), TimeDelta::FromMilliseconds(10));
	this->task_tracker_->WaitForCompletedTasks(kTaskCount);
	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}

	// Test that a pile of normal tasks and a delayed task run in the
	// time-to-run order.
	TYPED_TEST_P(SequencedTaskRunnerTest, DelayedTaskAfterManyLongTasks) {
	const int kTaskCount = 11;

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	for (int i = 0; i < kTaskCount - 1; i++) {
	this->task_tracker_->PostWrappedNonNestableTask(
	task_runner.get(),
	base::Bind(&PlatformThread::Sleep, TimeDelta::FromMilliseconds(50)));
	}
	this->task_tracker_->PostWrappedDelayedNonNestableTask(
	task_runner.get(), Closure(), TimeDelta::FromMilliseconds(10));
	this->task_tracker_->WaitForCompletedTasks(kTaskCount);
	this->delegate_.StopTaskRunner();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	}


	// TODO(francoisk777@gmail.com) Add a test, similiar to the above, which runs
	// some tasked nestedly (which should be implemented in the test
	// delegate). Also add, to the the test delegate, a predicate which checks
	// whether the implementation supports nested tasks.
	//

	// The SequencedTaskRunnerTest test case verifies behaviour that is expected
	// from a sequenced task runner in order to be conformant.
	REGISTER_TYPED_TEST_CASE_P(SequencedTaskRunnerTest,
	SequentialNonNestable,
	SequentialNestable,
	SequentialDelayedNonNestable,
	NonNestablePostFromNonNestableTask,
	DelayedTasksSameDelay,
	DelayedTaskAfterLongTask,
	DelayedTaskAfterManyLongTasks);

	template <typename TaskRunnerTestDelegate>
	class SequencedTaskRunnerDelayedTest
	: public SequencedTaskRunnerTest<TaskRunnerTestDelegate> {};

	TYPED_TEST_CASE_P(SequencedTaskRunnerDelayedTest);

	// This test posts a delayed task, and checks that the task is run later than
	// the specified time.
	TYPED_TEST_P(SequencedTaskRunnerDelayedTest, DelayedTaskBasic) {
	const int kTaskCount = 1;
	const TimeDelta kDelay = TimeDelta::FromMilliseconds(100);

	this->delegate_.StartTaskRunner();
	const scoped_refptr<SequencedTaskRunner> task_runner =
	this->delegate_.GetTaskRunner();

	Time time_before_run = Time::Now();
	this->task_tracker_->PostWrappedDelayedNonNestableTask(task_runner.get(),
	Closure(), kDelay);
	this->task_tracker_->WaitForCompletedTasks(kTaskCount);
	this->delegate_.StopTaskRunner();
	Time time_after_run = Time::Now();

	EXPECT_TRUE(CheckNonNestableInvariants(this->task_tracker_->GetTaskEvents(),
	kTaskCount));
	EXPECT_LE(kDelay, time_after_run - time_before_run);
	}

	// SequencedTaskRunnerDelayedTest tests that the \|delay\| parameter of
	// is used to actually wait for \|delay\| ms before executing the task.
	// This is not mandatory for a SequencedTaskRunner to be compliant.
	REGISTER_TYPED_TEST_CASE_P(SequencedTaskRunnerDelayedTest, DelayedTaskBasic);

	} // namespace base

	#endif // BASE_TEST_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_