base/test/task_runner_test_template.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This class defines tests that implementations of TaskRunner should
   6 // pass in order to be conformant.  Here's how you use it to test your
   7 // implementation.
   8 //
   9 // Say your class is called MyTaskRunner.  Then you need to define a
  10 // class called MyTaskRunnerTestDelegate in my_task_runner_unittest.cc
  11 // like this:
  12 //
  13 //   class MyTaskRunnerTestDelegate {
  14 //    public:
  15 //     // Tasks posted to the task runner after this and before
  16 //     // StopTaskRunner() is called is called should run successfully.
  17 //     void StartTaskRunner() {
  18 //       ...
  19 //     }
  20 //
  21 //     // Should return the task runner implementation.  Only called
  22 //     // after StartTaskRunner and before StopTaskRunner.
  23 //     scoped_refptr<MyTaskRunner> GetTaskRunner() {
  24 //       ...
  25 //     }
  26 //
  27 //     // Stop the task runner and make sure all tasks posted before
  28 //     // this is called are run. Caveat: delayed tasks are not run,
  29        // they're simply deleted.
  30 //     void StopTaskRunner() {
  31 //       ...
  32 //     }
  33 //   };
  34 //
  35 // The TaskRunnerTest test harness will have a member variable of
  36 // this delegate type and will call its functions in the various
  37 // tests.
  38 //
  39 // Then you simply #include this file as well as gtest.h and add the
  40 // following statement to my_task_runner_unittest.cc:
  41 //
  42 //   INSTANTIATE_TYPED_TEST_CASE_P(
  43 //       MyTaskRunner, TaskRunnerTest, MyTaskRunnerTestDelegate);
  44 //
  45 // Easy!
  46
  47 #ifndef BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
  48 #define BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
  49
  50 #include <cstddef>
  51 #include <map>
  52
  53 #include "base/basictypes.h"
  54 #include "base/bind.h"
  55 #include "base/callback.h"
  56 #include "base/location.h"
  57 #include "base/memory/ref_counted.h"
  58 #include "base/single_thread_task_runner.h"
  59 #include "base/synchronization/condition_variable.h"
  60 #include "base/synchronization/lock.h"
  61 #include "base/task_runner.h"
  62 #include "base/threading/thread.h"
  63 #include "base/tracked_objects.h"
  64 #include "testing/gtest/include/gtest/gtest.h"
  65
  66 namespace base {
  67
  68 namespace internal {
  69
  70 // Utility class that keeps track of how many times particular tasks
  71 // are run.
  72 class TaskTracker : public RefCountedThreadSafe<TaskTracker> {
  73  public:
  74   TaskTracker();
  75
  76   // Returns a closure that runs the given task and increments the run
  77   // count of |i| by one.  |task| may be null.  It is guaranteed that
  78   // only one task wrapped by a given tracker will be run at a time.
  79   Closure WrapTask(const Closure& task, int i);
  80
  81   std::map<int, int> GetTaskRunCounts() const;
  82
  83   // Returns after the tracker observes a total of |count| task completions.
  84   void WaitForCompletedTasks(int count);
  85
  86  private:
  87   friend class RefCountedThreadSafe<TaskTracker>;
  88
  89   ~TaskTracker();
  90
  91   void RunTask(const Closure& task, int i);
  92
  93   mutable Lock lock_;
  94   std::map<int, int> task_run_counts_;
  95   int task_runs_;
  96   ConditionVariable task_runs_cv_;
  97
  98   DISALLOW_COPY_AND_ASSIGN(TaskTracker);
  99 };
 100
 101 }  // namespace internal
 102
 103 template <typename TaskRunnerTestDelegate>
 104 class TaskRunnerTest : public testing::Test {
 105  protected:
 106   TaskRunnerTest() : task_tracker_(new internal::TaskTracker()) {}
 107
 108   const scoped_refptr<internal::TaskTracker> task_tracker_;
 109   TaskRunnerTestDelegate delegate_;
 110 };
 111
 112 TYPED_TEST_CASE_P(TaskRunnerTest);
 113
 114 // We can't really test much, since TaskRunner provides very few
 115 // guarantees.
 116
 117 // Post a bunch of tasks to the task runner.  They should all
 118 // complete.
 119 TYPED_TEST_P(TaskRunnerTest, Basic) {
 120   std::map<int, int> expected_task_run_counts;
 121
 122   this->delegate_.StartTaskRunner();
 123   scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
 124   // Post each ith task i+1 times.
 125   for (int i = 0; i < 20; ++i) {
 126     const Closure& ith_task = this->task_tracker_->WrapTask(Closure(), i);
 127     for (int j = 0; j < i + 1; ++j) {
 128       task_runner->PostTask(FROM_HERE, ith_task);
 129       ++expected_task_run_counts[i];
 130     }
 131   }
 132   this->delegate_.StopTaskRunner();
 133
 134   EXPECT_EQ(expected_task_run_counts,
 135             this->task_tracker_->GetTaskRunCounts());
 136 }
 137
 138 // Post a bunch of delayed tasks to the task runner.  They should all
 139 // complete.
 140 TYPED_TEST_P(TaskRunnerTest, Delayed) {
 141   std::map<int, int> expected_task_run_counts;
 142   int expected_total_tasks = 0;
 143
 144   this->delegate_.StartTaskRunner();
 145   scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
 146   // Post each ith task i+1 times with delays from 0-i.
 147   for (int i = 0; i < 20; ++i) {
 148     const Closure& ith_task = this->task_tracker_->WrapTask(Closure(), i);
 149     for (int j = 0; j < i + 1; ++j) {
 150       task_runner->PostDelayedTask(
 151           FROM_HERE, ith_task, base::TimeDelta::FromMilliseconds(j));
 152       ++expected_task_run_counts[i];
 153       ++expected_total_tasks;
 154     }
 155   }
 156   this->task_tracker_->WaitForCompletedTasks(expected_total_tasks);
 157   this->delegate_.StopTaskRunner();
 158
 159   EXPECT_EQ(expected_task_run_counts,
 160             this->task_tracker_->GetTaskRunCounts());
 161 }
 162
 163 namespace internal {
 164
 165 // Calls RunsTasksOnCurrentThread() on |task_runner| and expects it to
 166 // equal |expected_value|.
 167 void ExpectRunsTasksOnCurrentThread(
 168     bool expected_value,
 169     const scoped_refptr<TaskRunner>& task_runner);
 170
 171 }  // namespace internal
 172
 173 // Post a bunch of tasks to the task runner as well as to a separate
 174 // thread, each checking the value of RunsTasksOnCurrentThread(),
 175 // which should return true for the tasks posted on the task runner
 176 // and false for the tasks posted on the separate thread.
 177 TYPED_TEST_P(TaskRunnerTest, RunsTasksOnCurrentThread) {
 178   std::map<int, int> expected_task_run_counts;
 179
 180   Thread thread("Non-task-runner thread");
 181   ASSERT_TRUE(thread.Start());
 182   this->delegate_.StartTaskRunner();
 183
 184   scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
 185   // Post each ith task i+1 times on the task runner and i+1 times on
 186   // the non-task-runner thread.
 187   for (int i = 0; i < 20; ++i) {
 188     const Closure& ith_task_runner_task =
 189         this->task_tracker_->WrapTask(
 190             Bind(&internal::ExpectRunsTasksOnCurrentThread,
 191                  true, task_runner),
 192             i);
 193     const Closure& ith_non_task_runner_task =
 194         this->task_tracker_->WrapTask(
 195             Bind(&internal::ExpectRunsTasksOnCurrentThread,
 196                  false, task_runner),
 197             i);
 198     for (int j = 0; j < i + 1; ++j) {
 199       task_runner->PostTask(FROM_HERE, ith_task_runner_task);
 200       thread.task_runner()->PostTask(FROM_HERE, ith_non_task_runner_task);
 201       expected_task_run_counts[i] += 2;
 202     }
 203   }
 204
 205   this->delegate_.StopTaskRunner();
 206   thread.Stop();
 207
 208   EXPECT_EQ(expected_task_run_counts,
 209             this->task_tracker_->GetTaskRunCounts());
 210 }
 211
 212 REGISTER_TYPED_TEST_CASE_P(
 213     TaskRunnerTest, Basic, Delayed, RunsTasksOnCurrentThread);
 214
 215 }  // namespace base
 216
 217 #endif  // BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_