TaskScheduler: Move TaskFactory out of scheduler_thread_pool_unittest.cc

base/task_scheduler/test_task_factory.h

+// Copyright 2016 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.
+
+#ifndef BASE_TASK_SCHEDULER_TEST_TASK_FACTORY_H_
+#define BASE_TASK_SCHEDULER_TEST_TASK_FACTORY_H_
+
+#include <stddef.h>
+
+#include <unordered_set>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/condition_variable.h"
+#include "base/synchronization/lock.h"
+#include "base/task_runner.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/threading/thread_checker_impl.h"
+
+namespace base {
+
+class WaitableEvent;
+
+namespace internal {
+namespace test {
+
+// A TestTaskFactory posts tasks to a TaskRunner and verifies that they run as
+// expected. Generates a test failure when:
+// - The ExecutionMode of the TaskRunner is SEQUENCED or SINGLE_THREADED and
+//   Tasks don't run in posting order.
+// - The ExecutionMode of the TaskRunner is SINGLE_THREADED and Tasks don't
+//   run on the same thread.
+// - A Task runs more than once.
+class TestTaskFactory {
+ public:
+  enum class PostNestedTask {
+    YES,
+    NO,
+  };
+
+  // Constructs a TestTaskFactory that posts tasks to |task_runner|.
+  // |execution_mode| is the ExecutionMode of |task_runner|.
+  TestTaskFactory(scoped_refptr<TaskRunner> task_runner,
+                  ExecutionMode execution_mode);
+
+  ~TestTaskFactory();
+
+  // Posts a task. If |post_nested_task| is YES, the task will post a new task
+  // when it runs. If |event| is set, the task will block until it is signaled.
+  // Returns true if the task is posted.
+  bool PostTask(PostNestedTask post_nested_task, WaitableEvent* event);
+
+  // Waits for all tasks posted by PostTask() to start running. It is not
+  // guaranteed that the tasks have completed their execution when this returns.
+  void WaitForAllTasksToRun() const;
+
+  const TaskRunner* task_runner() const { return task_runner_.get(); }
+
+ private:
+  void RunTaskCallback(size_t task_index,
+                       PostNestedTask post_nested_task,
+                       WaitableEvent* event);
+
+  // Synchronizes access to all members.
+  mutable Lock lock_;
+
+  // Condition variable signaled when a task runs.
+  mutable ConditionVariable cv_;
+
+  // Task runner through which this factory posts tasks.
+  const scoped_refptr<TaskRunner> task_runner_;
+
+  // Execution mode of |task_runner_|.
+  const ExecutionMode execution_mode_;
+
+  // Number of tasks posted by PostTask().
+  size_t num_posted_tasks_ = 0;
+
+  // Indexes of tasks that ran.
+  std::unordered_set<size_t> ran_tasks_;
+
+  // Used to verify that all tasks run on the same thread when |execution_mode_|
+  // is SINGLE_THREADED.
+  ThreadCheckerImpl thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestTaskFactory);
+};
+
+}  // namespace test
+}  // namespace internal
+}  // namespace base
+
+#endif  // BASE_TASK_SCHEDULER_TEST_TASK_FACTORY_H_