Support PostTaskAndReply from a sequenced task.

base/threading/post_task_and_reply_impl_unittest.cc

+// 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/threading/post_task_and_reply_impl.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/test/test_simple_task_runner.h"
+#include "base/threading/sequenced_task_runner_handle.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::_;
+
+namespace base {
+namespace internal {
+
+namespace {
+
+class ObjectToDelete : public RefCounted<ObjectToDelete> {
+ public:
+  // |delete_flag| is set to true when this object is deleted
+  ObjectToDelete(bool* delete_flag) : delete_flag_(delete_flag) {

[robliao, 2016/07/27 17:50:07]

Explicit

[fdoray, 2016/07/28 13:40:48]

Done.

+    EXPECT_FALSE(*delete_flag_);

[robliao, 2016/07/27 17:50:07]

Should the test be allowed to proceed if this is fails?

[fdoray, 2016/07/28 13:40:48]

Probably not. But ASSERTs are not supported in a constructor:

../../base/threading/post_task_and_reply_impl_unittest.cc:27:5: error:
constructor 'ObjectToDelete' must not return void expression
    ASSERT_TRUE(delete_flag);
    ^~~~~~~~~~~~~~~~~~~~~~~~
../../testing/gtest/include/gtest/gtest.h:1871:23: note: expanded from macro
'ASSERT_TRUE'
                      GTEST_FATAL_FAILURE_)
                      ^~~~~~~~~~~~~~~~~~~~~
../../testing/gtest/include/gtest/internal/gtest-internal.h:1192:5: note:
expanded from macro 'GTEST_TEST_BOOLEAN_'
    fail(::testing::internal::GetBoolAssertionFailureMessage(\
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../testing/gtest/include/gtest/internal/gtest-internal.h:1110:3: note:
expanded from macro 'GTEST_FATAL_FAILURE_'
  return GTEST_MESSAGE_(message, ::testing::TestPartResult::kFatalFailure)

[robliao, 2016/07/28 19:25:26]

Ah, that's indeed because of the early return. Probably not worth it to do the
whole factory conversion just for this.

+  }

[robliao, 2016/07/27 17:50:07]

Add an ASSERT_TRUE(delete_flag)

[fdoray, 2016/07/28 13:40:48]

Added EXPECT_TRUE. ASSERT_TRUE isn't supported in a constructor. EXPECT_TRUE is
a better solution than DCHECK because it produces a nice error message (before
crashing) even when !DCHECK_IS_ON().

+
+ private:
+  friend class RefCounted<ObjectToDelete>;
+  ~ObjectToDelete() { *delete_flag_ = true; }
+
+  bool* const delete_flag_;
+
+  DISALLOW_COPY_AND_ASSIGN(ObjectToDelete);
+};
+
+class MockObject {
+ public:
+  MockObject() = default;
+
+  MOCK_METHOD1(Task, void(scoped_refptr<ObjectToDelete>));
+
+  void Reply(bool* delete_flag) {
+    // Expect the task's deletion flag to be set before the reply runs.
+    EXPECT_TRUE(*delete_flag);
+    ReplyMock();
+  }
+
+  MOCK_METHOD0(ReplyMock, void());
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MockObject);
+};
+
+}  // namespace
+
+TEST(PostTaskAndReplyImplTest, PostTaskAndReply) {
+  scoped_refptr<TestSimpleTaskRunner> task_runner(new TestSimpleTaskRunner);
+  scoped_refptr<TestSimpleTaskRunner> current_runner(new TestSimpleTaskRunner);
+  SequencedTaskRunnerHandle sequenced_task_runner_handle(current_runner);
+
+  testing::StrictMock<MockObject> mock_object;
+  bool delete_flag = false;
+
+  EXPECT_TRUE(internal::PostTaskAndReply(
+      FROM_HERE, Bind(&MockObject::Task, Unretained(&mock_object),
+                      make_scoped_refptr(new ObjectToDelete(&delete_flag))),
+      Bind(&MockObject::Reply, Unretained(&mock_object),
+           Unretained(&delete_flag)),
+      Bind(&TestSimpleTaskRunner::PostTask, task_runner.get())));
+
+  // Expect no reply in |current_runner|.
+  EXPECT_FALSE(current_runner->HasPendingTask());
+
+  // Expect the task to be posted to |task_runner|.
+  EXPECT_TRUE(task_runner->HasPendingTask());
+  EXPECT_CALL(mock_object, Task(_));
+  task_runner->RunUntilIdle();
+  testing::Mock::VerifyAndClear(&mock_object);
+
+  // Expect the task's argument not to have been deleted yet.
+  EXPECT_FALSE(delete_flag);

[robliao, 2016/07/27 17:50:07]

There should also be an EXPECT_TRUE for this after everything runs, right?

[fdoray, 2016/07/28 13:40:48]

Done.

+
+  // Expect the reply to be posted to |current_runner|.
+  EXPECT_FALSE(task_runner->HasPendingTask());
+  EXPECT_TRUE(current_runner->HasPendingTask());
+  EXPECT_CALL(mock_object, ReplyMock());
+  current_runner->RunUntilIdle();
+  testing::Mock::VerifyAndClear(&mock_object);
+
+  // Expect no pending task in |task_runner| and |current_runner|.
+  EXPECT_FALSE(task_runner->HasPendingTask());
+  EXPECT_FALSE(current_runner->HasPendingTask());
+}
+
+}  // namespace internal
+}  // namespace base