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// 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.
// This file defines tests that implementations of TaskRunner should
// pass in order to be conformant, as well as test cases for optional behavior.
// Here's how you use it to test your implementation.
//
// Say your class is called MyTaskRunner. Then you need to define a
// class called MyTaskRunnerTestDelegate in my_task_runner_unittest.cc
// like this:
//
// class MyTaskRunnerTestDelegate {
// public:
// // Tasks posted to the task runner after this and before
// // StopTaskRunner() is called is called should run successfully.
// void StartTaskRunner() {
// ...
// }
//
// // Should return the task runner implementation. Only called
// // after StartTaskRunner and before StopTaskRunner.
// scoped_refptr<MyTaskRunner> GetTaskRunner() {
// ...
// }
//
// // Stop the task runner and make sure all tasks posted before
// // this is called are run. Caveat: delayed tasks are not run,
// they're simply deleted.
// void StopTaskRunner() {
// ...
// }
// };
//
// The TaskRunnerTest test harness will have a member variable of
// this delegate type and will call its functions in the various
// tests.
//
// Then you simply #include this file as well as gtest.h and add the
// following statement to my_task_runner_unittest.cc:
//
// INSTANTIATE_TYPED_TEST_CASE_P(
// MyTaskRunner, TaskRunnerTest, MyTaskRunnerTestDelegate);
//
// Easy!
//
// The optional test harnesses TaskRunnerAffinityTest can be
// instanciated in the same way, using the same delegate:
//
// INSTANTIATE_TYPED_TEST_CASE_P(
// MyTaskRunner, TaskRunnerAffinityTest, MyTaskRunnerTestDelegate);
#ifndef BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
#define BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
#include <cstddef>
#include <map>
#include "base/bind.h"
#include "base/callback.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/condition_variable.h"
#include "base/synchronization/lock.h"
#include "base/task_runner.h"
#include "base/threading/thread.h"
#include "base/tracked_objects.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace internal {
// Utility class that keeps track of how many times particular tasks
// are run.
class TaskTracker : public RefCountedThreadSafe<TaskTracker> {
public:
TaskTracker();
// Returns a closure that runs the given task and increments the run
// count of |i| by one. |task| may be null. It is guaranteed that
// only one task wrapped by a given tracker will be run at a time.
Closure WrapTask(const Closure& task, int i);
std::map<int, int> GetTaskRunCounts() const;
// Returns after the tracker observes a total of |count| task completions.
void WaitForCompletedTasks(int count);
private:
friend class RefCountedThreadSafe<TaskTracker>;
~TaskTracker();
void RunTask(const Closure& task, int i);
mutable Lock lock_;
std::map<int, int> task_run_counts_;
int task_runs_;
ConditionVariable task_runs_cv_;
DISALLOW_COPY_AND_ASSIGN(TaskTracker);
};
} // namespace internal
template <typename TaskRunnerTestDelegate>
class TaskRunnerTest : public testing::Test {
protected:
TaskRunnerTest() : task_tracker_(new internal::TaskTracker()) {}
const scoped_refptr<internal::TaskTracker> task_tracker_;
TaskRunnerTestDelegate delegate_;
};
TYPED_TEST_CASE_P(TaskRunnerTest);
// We can't really test much, since TaskRunner provides very few
// guarantees.
// Post a bunch of tasks to the task runner. They should all
// complete.
TYPED_TEST_P(TaskRunnerTest, Basic) {
std::map<int, int> expected_task_run_counts;
this->delegate_.StartTaskRunner();
scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
// Post each ith task i+1 times.
for (int i = 0; i < 20; ++i) {
const Closure& ith_task = this->task_tracker_->WrapTask(Closure(), i);
for (int j = 0; j < i + 1; ++j) {
task_runner->PostTask(FROM_HERE, ith_task);
++expected_task_run_counts[i];
}
}
this->delegate_.StopTaskRunner();
EXPECT_EQ(expected_task_run_counts,
this->task_tracker_->GetTaskRunCounts());
}
// Post a bunch of delayed tasks to the task runner. They should all
// complete.
TYPED_TEST_P(TaskRunnerTest, Delayed) {
std::map<int, int> expected_task_run_counts;
int expected_total_tasks = 0;
this->delegate_.StartTaskRunner();
scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
// Post each ith task i+1 times with delays from 0-i.
for (int i = 0; i < 20; ++i) {
const Closure& ith_task = this->task_tracker_->WrapTask(Closure(), i);
for (int j = 0; j < i + 1; ++j) {
task_runner->PostDelayedTask(
FROM_HERE, ith_task, base::TimeDelta::FromMilliseconds(j));
++expected_task_run_counts[i];
++expected_total_tasks;
}
}
this->task_tracker_->WaitForCompletedTasks(expected_total_tasks);
this->delegate_.StopTaskRunner();
EXPECT_EQ(expected_task_run_counts,
this->task_tracker_->GetTaskRunCounts());
}
// The TaskRunnerTest test case verifies behaviour that is expected from a
// task runner in order to be conformant.
REGISTER_TYPED_TEST_CASE_P(TaskRunnerTest, Basic, Delayed);
namespace internal {
// Calls RunsTasksOnCurrentThread() on |task_runner| and expects it to
// equal |expected_value|.
void ExpectRunsTasksOnCurrentThread(
bool expected_value,
const scoped_refptr<TaskRunner>& task_runner);
} // namespace internal
template <typename TaskRunnerTestDelegate>
class TaskRunnerAffinityTest : public TaskRunnerTest<TaskRunnerTestDelegate> {};
TYPED_TEST_CASE_P(TaskRunnerAffinityTest);
// Post a bunch of tasks to the task runner as well as to a separate
// thread, each checking the value of RunsTasksOnCurrentThread(),
// which should return true for the tasks posted on the task runner
// and false for the tasks posted on the separate thread.
TYPED_TEST_P(TaskRunnerAffinityTest, RunsTasksOnCurrentThread) {
std::map<int, int> expected_task_run_counts;
Thread thread("Non-task-runner thread");
ASSERT_TRUE(thread.Start());
this->delegate_.StartTaskRunner();
scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
// Post each ith task i+1 times on the task runner and i+1 times on
// the non-task-runner thread.
for (int i = 0; i < 20; ++i) {
const Closure& ith_task_runner_task =
this->task_tracker_->WrapTask(
Bind(&internal::ExpectRunsTasksOnCurrentThread,
true, task_runner),
i);
const Closure& ith_non_task_runner_task =
this->task_tracker_->WrapTask(
Bind(&internal::ExpectRunsTasksOnCurrentThread,
false, task_runner),
i);
for (int j = 0; j < i + 1; ++j) {
task_runner->PostTask(FROM_HERE, ith_task_runner_task);
thread.task_runner()->PostTask(FROM_HERE, ith_non_task_runner_task);
expected_task_run_counts[i] += 2;
}
}
this->delegate_.StopTaskRunner();
thread.Stop();
EXPECT_EQ(expected_task_run_counts,
this->task_tracker_->GetTaskRunCounts());
}
// TaskRunnerAffinityTest tests that the TaskRunner implementation
// can determine if tasks will never be run on a specific thread.
REGISTER_TYPED_TEST_CASE_P(TaskRunnerAffinityTest, RunsTasksOnCurrentThread);
} // namespace base
#endif // BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_