Flush SequenceWorkerPool tasks after each unit test.

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.
 
 // This class 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_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_
 #define BASE_SEQUENCED_TASK_RUNNER_TEST_TEMPLATE_H_
 
 #include <cstddef>
 #include <iosfwd>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback.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.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 namespace internal {
 
 struct TaskEvent {
   enum Type { POST, START, END };
@@ skipping 23 matching lines @@
       const Closure& task,
       TimeDelta delay);
 
   // Posts |task_count| non-nestable tasks.
   void PostNonNestableTasks(
       const scoped_refptr<SequencedTaskRunner>& task_runner,
       int task_count);
 
   const std::vector<TaskEvent>& GetTaskEvents() const;
 
+  void WaitForCountTasksToComplete(int count);

[akalin, 2013/02/26 00:12:23]

There's a bit of an ambiguity here -- do you mean wait for a total of |count|
tasks to complete, or |count| additional tasks? I'm guessing the former, since
the latter seems racy (without another variable).

If so, perhaps a better name would be:

WaitForCompletedTasks(count);

or something that removes the ambiguity?

Also, should probably add a comment either way.

[michaeln, 2013/02/27 00:57:12]

Done.

+
  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_ and next_post_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 ends we've received.

[akalin, 2013/02/26 00:12:23]

task ends -> task end events

[michaeln, 2013/02/27 00:57:12]

Done.

+  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()) {}
+      : 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
@@ skipping 58 matching lines @@
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();
 
   for (int i = 0; i < kTaskCount; ++i) {
     this->task_tracker_->PostWrappedDelayedNonNestableTask(
         task_runner,
         Closure(),
         TimeDelta::FromMilliseconds(kDelayIncrementMs * i));
   }
 
+  this->task_tracker_->WaitForCountTasksToComplete(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) {
@@ skipping 33 matching lines @@
   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, Closure(), kDelay);
+  this->task_tracker_->WaitForCountTasksToComplete(1);

[akalin, 2013/02/26 00:12:23]

use kTaskCount here, too

[michaeln, 2013/02/27 00:57:12]

Done.

   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);
 }
 
 // This test posts two tasks with the same delay, and checks that the tasks are
 // run in the order in which they were posted.
@@ skipping 14 matching lines @@
   const TimeDelta kDelay = TimeDelta::FromMilliseconds(100);
 
   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();
 
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner, Closure(), kDelay);
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner, Closure(), kDelay);
+  this->task_tracker_->WaitForCountTasksToComplete(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) {
   // TODO(akalin): Remove this check (http://crbug.com/149144).
   if (!this->delegate_.TaskRunnerHandlesNonZeroDelays()) {
     DLOG(INFO) << "This SequencedTaskRunner doesn't handle "
         "non-zero delays; skipping";
     return;
   }
 
   const int kTaskCount = 2;
 
   this->delegate_.StartTaskRunner();
   const scoped_refptr<SequencedTaskRunner> task_runner =
       this->delegate_.GetTaskRunner();
 
   this->task_tracker_->PostWrappedNonNestableTask(
       task_runner, base::Bind(&PlatformThread::Sleep,
                               TimeDelta::FromMilliseconds(50)));
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner, Closure(), TimeDelta::FromMilliseconds(10));
+  this->task_tracker_->WaitForCountTasksToComplete(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) {
   // TODO(akalin): Remove this check (http://crbug.com/149144).
   if (!this->delegate_.TaskRunnerHandlesNonZeroDelays()) {
     DLOG(INFO) << "This SequencedTaskRunner doesn't handle "
         "non-zero delays; skipping";
     return;
   }
 
   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, base::Bind(&PlatformThread::Sleep,
                                 TimeDelta::FromMilliseconds(50)));
   }
   this->task_tracker_->PostWrappedDelayedNonNestableTask(
       task_runner, Closure(), TimeDelta::FromMilliseconds(10));
+  this->task_tracker_->WaitForCountTasksToComplete(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.
 //
 
 REGISTER_TYPED_TEST_CASE_P(SequencedTaskRunnerTest,
                            SequentialNonNestable,
                            SequentialNestable,
                            SequentialDelayedNonNestable,
                            NonNestablePostFromNonNestableTask,
                            DelayedTaskBasic,
                            DelayedTasksSameDelay,
                            DelayedTaskAfterLongTask,
                            DelayedTaskAfterManyLongTasks);
 
 }  // namespace base
 
 #endif  // BASE_TASK_RUNNER_TEST_TEMPLATE_H_