Create base::test::ScopedTaskScheduler.
ScopedTaskScheduler initializes a TaskScheduler and allows usage of the
base/task_scheduler/post_task.h API within a scope. To make tests
deterministic, the TaskScheduler initialized by ScopedTaskScheduler has
a single thread.
BUG=553459
Review-Url: https://codereview.chromium.org/2511473004
Cr-Commit-Position: refs/heads/master@{#433702}
CrOS-Libchrome-Original-Commit: 8602d8a7269695a80f9d796ba7b2d69209f8cbdd
diff --git a/base/task_scheduler/task_scheduler.h b/base/task_scheduler/task_scheduler.h
index d4084c6..cbfaae9 100644
--- a/base/task_scheduler/task_scheduler.h
+++ b/base/task_scheduler/task_scheduler.h
@@ -82,6 +82,10 @@
// other threads during the call. Returns immediately when shutdown completes.
virtual void FlushForTesting() = 0;
+ // Joins all threads of this scheduler. Tasks that are already running are
+ // allowed to complete their execution. This can only be called once.
+ virtual void JoinForTesting() = 0;
+
// CreateAndSetSimpleTaskScheduler(), CreateAndSetDefaultTaskScheduler(), and
// SetInstance() register a TaskScheduler to handle tasks posted through the
// post_task.h API for this process. The registered TaskScheduler will only be
diff --git a/base/task_scheduler/task_scheduler_impl.h b/base/task_scheduler/task_scheduler_impl.h
index 1483c5d..9a16103 100644
--- a/base/task_scheduler/task_scheduler_impl.h
+++ b/base/task_scheduler/task_scheduler_impl.h
@@ -62,10 +62,7 @@
std::vector<const HistogramBase*> GetHistograms() const override;
void Shutdown() override;
void FlushForTesting() override;
-
- // Joins all threads of this scheduler. Tasks that are already running are
- // allowed to complete their execution. This can only be called once.
- void JoinForTesting();
+ void JoinForTesting() override;
private:
explicit TaskSchedulerImpl(const WorkerPoolIndexForTraitsCallback&
diff --git a/base/test/scoped_task_scheduler.cc b/base/test/scoped_task_scheduler.cc
new file mode 100644
index 0000000..7696537
--- /dev/null
+++ b/base/test/scoped_task_scheduler.cc
@@ -0,0 +1,29 @@
+// 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.
+
+#include "base/test/scoped_task_scheduler.h"
+
+#include "base/task_scheduler/task_scheduler.h"
+
+namespace base {
+namespace test {
+
+ScopedTaskScheduler::ScopedTaskScheduler() {
+ DCHECK(!TaskScheduler::GetInstance());
+
+ // Create a TaskScheduler with a single thread to make tests deterministic.
+ constexpr int kMaxThreads = 1;
+ TaskScheduler::CreateAndSetSimpleTaskScheduler(kMaxThreads);
+ task_scheduler_ = TaskScheduler::GetInstance();
+}
+
+ScopedTaskScheduler::~ScopedTaskScheduler() {
+ DCHECK_EQ(task_scheduler_, TaskScheduler::GetInstance());
+ TaskScheduler::GetInstance()->Shutdown();
+ TaskScheduler::GetInstance()->JoinForTesting();
+ TaskScheduler::SetInstance(nullptr);
+}
+
+} // namespace test
+} // namespace base
diff --git a/base/test/scoped_task_scheduler.h b/base/test/scoped_task_scheduler.h
new file mode 100644
index 0000000..f2b252b
--- /dev/null
+++ b/base/test/scoped_task_scheduler.h
@@ -0,0 +1,41 @@
+// 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_TEST_SCOPED_TASK_SCHEDULER_H_
+#define BASE_TEST_SCOPED_TASK_SCHEDULER_H_
+
+#include "base/macros.h"
+
+namespace base {
+
+class TaskScheduler;
+
+namespace test {
+
+// Initializes a TaskScheduler and allows usage of the
+// base/task_scheduler/post_task.h API within its scope.
+class ScopedTaskScheduler {
+ public:
+ // Initializes a TaskScheduler with default arguments.
+ ScopedTaskScheduler();
+
+ // Waits until all TaskScheduler tasks blocking shutdown complete their
+ // execution (see TaskShutdownBehavior). Then, joins all TaskScheduler threads
+ // and deletes the TaskScheduler.
+ //
+ // Note that joining TaskScheduler threads may involve waiting for
+ // CONTINUE_ON_SHUTDOWN tasks to complete their execution. Normally, in
+ // production, the process exits without joining TaskScheduler threads.
+ ~ScopedTaskScheduler();
+
+ private:
+ const TaskScheduler* task_scheduler_ = nullptr;
+
+ DISALLOW_COPY_AND_ASSIGN(ScopedTaskScheduler);
+};
+
+} // namespace test
+} // namespace base
+
+#endif // BASE_TEST_SCOPED_TASK_SCHEDULER_H_
diff --git a/base/threading/sequenced_worker_pool_unittest.cc b/base/threading/sequenced_worker_pool_unittest.cc
index 39b424c..eccf15c 100644
--- a/base/threading/sequenced_worker_pool_unittest.cc
+++ b/base/threading/sequenced_worker_pool_unittest.cc
@@ -297,8 +297,7 @@
// Destroys and unregisters the registered TaskScheduler, if any.
void DeleteTaskScheduler() {
if (TaskScheduler::GetInstance()) {
- static_cast<internal::TaskSchedulerImpl*>(TaskScheduler::GetInstance())
- ->JoinForTesting();
+ TaskScheduler::GetInstance()->JoinForTesting();
TaskScheduler::SetInstance(nullptr);
}
}