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.
  29 //     void StopTaskRunner() {
  30 //       ...
  31 //     }
  32 //
  33 //     // Returns whether or not the task runner obeys non-zero delays.
  34 //     bool TaskRunnerHandlesNonZeroDelays() const {
  35 //       return true;
  36 //     }
  37 //   };
  38 //
  39 // The TaskRunnerTest test harness will have a member variable of
  40 // this delegate type and will call its functions in the various
  41 // tests.
  42 //
  43 // Then you simply #include this file as well as gtest.h and add the
  44 // following statement to my_task_runner_unittest.cc:
  45 //
  46 //   INSTANTIATE_TYPED_TEST_CASE_P(
  47 //       MyTaskRunner, TaskRunnerTest, MyTaskRunnerTestDelegate);
  48 //
  49 // Easy!
  50
  51 #ifndef BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
  52 #define BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_
  53
  54 #include <cstddef>
  55 #include <map>
  56
  57 #include "base/basictypes.h"
  58 #include "base/bind.h"
  59 #include "base/callback.h"
  60 #include "base/memory/ref_counted.h"
  61 #include "base/synchronization/lock.h"
  62 #include "base/task_runner.h"
  63 #include "base/threading/thread.h"
  64 #include "base/tracked_objects.h"
  65 #include "testing/gtest/include/gtest/gtest.h"
  66
  67 namespace base {
  68
  69 namespace internal {
  70
  71 // Utility class that keeps track of how many times particular tasks
  72 // are run.
  73 class TaskTracker : public RefCountedThreadSafe<TaskTracker> {
  74  public:
  75   TaskTracker();
  76
  77   // Returns a closure that runs the given task and increments the run
  78   // count of |i| by one.  |task| may be null.  It is guaranteed that
  79   // only one task wrapped by a given tracker will be run at a time.
  80   Closure WrapTask(const Closure& task, int i);
  81
  82   std::map<int, int> GetTaskRunCounts() const;
  83
  84  private:
  85   friend class RefCountedThreadSafe<TaskTracker>;
  86
  87   ~TaskTracker();
  88
  89   void RunTask(const Closure& task, int i);
  90
  91   mutable Lock task_run_counts_lock_;
  92   std::map<int, int> task_run_counts_;
  93
  94   DISALLOW_COPY_AND_ASSIGN(TaskTracker);
  95 };
  96
  97 }  // namespace internal
  98
  99 template <typename TaskRunnerTestDelegate>
 100 class TaskRunnerTest : public testing::Test {
 101  protected:
 102   TaskRunnerTest() : task_tracker_(new internal::TaskTracker()) {}
 103
 104   const scoped_refptr<internal::TaskTracker> task_tracker_;
 105   TaskRunnerTestDelegate delegate_;
 106 };
 107
 108 TYPED_TEST_CASE_P(TaskRunnerTest);
 109
 110 // We can't really test much, since TaskRunner provides very few
 111 // guarantees.
 112
 113 // Post a bunch of tasks to the task runner.  They should all
 114 // complete.
 115 TYPED_TEST_P(TaskRunnerTest, Basic) {
 116   std::map<int, int> expected_task_run_counts;
 117
 118   this->delegate_.StartTaskRunner();
 119   scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
 120   // Post each ith task i+1 times.
 121   for (int i = 0; i < 20; ++i) {
 122     const Closure& ith_task = this->task_tracker_->WrapTask(Closure(), i);
 123     for (int j = 0; j < i + 1; ++j) {
 124       task_runner->PostTask(FROM_HERE, ith_task);
 125       ++expected_task_run_counts[i];
 126     }
 127   }
 128   this->delegate_.StopTaskRunner();
 129
 130   EXPECT_EQ(expected_task_run_counts,
 131             this->task_tracker_->GetTaskRunCounts());
 132 }
 133
 134 // Post a bunch of delayed tasks to the task runner.  They should all
 135 // complete.
 136 TYPED_TEST_P(TaskRunnerTest, Delayed) {
 137   if (!this->delegate_.TaskRunnerHandlesNonZeroDelays()) {
 138     DLOG(INFO) << "This TaskRunner doesn't handle non-zero delays; skipping";
 139     return;
 140   }
 141
 142   std::map<int, int> expected_task_run_counts;
 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     }
 154   }
 155   this->delegate_.StopTaskRunner();
 156
 157   EXPECT_EQ(expected_task_run_counts,
 158             this->task_tracker_->GetTaskRunCounts());
 159 }
 160
 161 namespace internal {
 162
 163 // Calls RunsTasksOnCurrentThread() on |task_runner| and expects it to
 164 // equal |expected_value|.
 165 void ExpectRunsTasksOnCurrentThread(
 166     bool expected_value,
 167     const scoped_refptr<TaskRunner>& task_runner);
 168
 169 }  // namespace internal
 170
 171 // Post a bunch of tasks to the task runner as well as to a separate
 172 // thread, each checking the value of RunsTasksOnCurrentThread(),
 173 // which should return true for the tasks posted on the task runner
 174 // and false for the tasks posted on the separate thread.
 175 TYPED_TEST_P(TaskRunnerTest, RunsTasksOnCurrentThread) {
 176   std::map<int, int> expected_task_run_counts;
 177
 178   Thread thread("Non-task-runner thread");
 179   ASSERT_TRUE(thread.Start());
 180   this->delegate_.StartTaskRunner();
 181
 182   scoped_refptr<TaskRunner> task_runner = this->delegate_.GetTaskRunner();
 183   // Post each ith task i+1 times on the task runner and i+1 times on
 184   // the non-task-runner thread.
 185   for (int i = 0; i < 20; ++i) {
 186     const Closure& ith_task_runner_task =
 187         this->task_tracker_->WrapTask(
 188             Bind(&internal::ExpectRunsTasksOnCurrentThread,
 189                  true, task_runner),
 190             i);
 191     const Closure& ith_non_task_runner_task =
 192         this->task_tracker_->WrapTask(
 193             Bind(&internal::ExpectRunsTasksOnCurrentThread,
 194                  false, task_runner),
 195             i);
 196     for (int j = 0; j < i + 1; ++j) {
 197       task_runner->PostTask(FROM_HERE, ith_task_runner_task);
 198       thread.message_loop()->PostTask(FROM_HERE, ith_non_task_runner_task);
 199       expected_task_run_counts[i] += 2;
 200     }
 201   }
 202
 203   this->delegate_.StopTaskRunner();
 204   thread.Stop();
 205
 206   EXPECT_EQ(expected_task_run_counts,
 207             this->task_tracker_->GetTaskRunCounts());
 208 }
 209
 210 REGISTER_TYPED_TEST_CASE_P(
 211     TaskRunnerTest, Basic, Delayed, RunsTasksOnCurrentThread);
 212
 213 }  // namespace base
 214
 215 #endif  //#define BASE_TEST_TASK_RUNNER_TEST_TEMPLATE_H_