Move some generic functions to AudioManagerBase to be inherited by platform-specific AudioManager***

media/audio/linux/alsa_output_unittest.cc

 // 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.
 
 #include "base/message_loop.h"
 #include "base/stringprintf.h"
 #include "media/audio/linux/alsa_output.h"
 #include "media/audio/linux/alsa_wrapper.h"
 #include "media/audio/linux/audio_manager_linux.h"
 #include "media/base/data_buffer.h"
@@ skipping 60 matching lines @@
                                   uint8* dest, uint32 max_size,
                                   AudioBuffersState buffers_state));
   MOCK_METHOD2(OnError, void(AudioOutputStream* stream, int code));
 };
 
 class MockAudioManagerLinux : public AudioManagerLinux {
  public:
   MOCK_METHOD0(Init, void());
   MOCK_METHOD0(HasAudioOutputDevices, bool());
   MOCK_METHOD0(HasAudioInputDevices, bool());
-  MOCK_METHOD1(MakeAudioOutputStream, AudioOutputStream*(
-      const AudioParameters& params));
-  MOCK_METHOD2(MakeAudioInputStream, AudioInputStream*(
-      const AudioParameters& params, const std::string& device_id));
   MOCK_METHOD0(MuteAll, void());
   MOCK_METHOD0(UnMuteAll, void());
-  MOCK_METHOD1(ReleaseOutputStream, void(AudioOutputStream* stream));
+  MOCK_METHOD0(GetMaxAudioOutputStreamsAllowed, int());
+  MOCK_METHOD1(MakeAudioLinearOutputStream, AudioOutputStream*(
+      const AudioParameters& params));
+  MOCK_METHOD1(MakeAudioLowLatencyOutputStream, AudioOutputStream*(
+      const AudioParameters& params));
+  MOCK_METHOD2(MakeAudioLinearOutputStream, AudioInputStream*(
+      const AudioParameters& params, const std::string& device_id));
+  MOCK_METHOD2(MakeAudioLowLatencyInputStream, AudioInputStream*(
+      const AudioParameters& params, const std::string& device_id));
+
+  // We need to override this function because we want to skip the checking
+  // the number of active streams.
+  virtual void ReleaseOutputStream(AudioOutputStream* stream) OVERRIDE {
+    DCHECK(stream);
+    delete stream;
+  }
 
   // We don't mock this method since all tests will do the same thing
   // and use the current message loop.
   virtual scoped_refptr<base::MessageLoopProxy> GetMessageLoop() OVERRIDE {
     return MessageLoop::current()->message_loop_proxy();
   }
 };
 
 class AlsaPcmOutputStreamTest : public testing::Test {
  protected:
   AlsaPcmOutputStreamTest() {
     mock_manager_.reset(new StrictMock<MockAudioManagerLinux>());
-    test_stream_.reset(CreateStream(kTestChannelLayout));
+    test_stream_ = CreateStream(kTestChannelLayout);
   }
 
   virtual ~AlsaPcmOutputStreamTest() {
-    test_stream_.reset(NULL);
+    test_stream_ = NULL;
   }
 
   AlsaPcmOutputStream* CreateStream(ChannelLayout layout) {
     return CreateStream(layout, kTestFramesPerPacket);
   }
 
   AlsaPcmOutputStream* CreateStream(ChannelLayout layout,
                                     int32 samples_per_packet) {
     AudioParameters params(kTestFormat, layout, kTestSampleRate,
                            kTestBitsPerSample, samples_per_packet);
@@ skipping 43 matching lines @@
   static char kSurround41[];
   static char kSurround50[];
   static char kSurround51[];
   static char kSurround70[];
   static char kSurround71[];
   static void* kFakeHints[];
 
   StrictMock<MockAlsaWrapper> mock_alsa_wrapper_;
   scoped_ptr<StrictMock<MockAudioManagerLinux> > mock_manager_;
   MessageLoop message_loop_;
-  scoped_ptr<AlsaPcmOutputStream> test_stream_;
+  AlsaPcmOutputStream* test_stream_;
   scoped_refptr<media::DataBuffer> packet_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmOutputStreamTest);
 };
 
 const ChannelLayout AlsaPcmOutputStreamTest::kTestChannelLayout =
     CHANNEL_LAYOUT_STEREO;
 const int AlsaPcmOutputStreamTest::kTestSampleRate =
     AudioParameters::kAudioCDSampleRate;
@@ skipping 20 matching lines @@
 char AlsaPcmOutputStreamTest::kSurround70[] = "surround70:CARD=foo,DEV=0";
 char AlsaPcmOutputStreamTest::kSurround71[] = "surround71:CARD=foo,DEV=0";
 void* AlsaPcmOutputStreamTest::kFakeHints[] = {
     kSurround40, kSurround41, kSurround50, kSurround51,
     kSurround70, kSurround71, NULL };
 
 TEST_F(AlsaPcmOutputStreamTest, ConstructedState) {
   EXPECT_EQ(AlsaPcmOutputStream::kCreated, test_stream_->state());
 
   // Should support mono.
-  test_stream_.reset(CreateStream(CHANNEL_LAYOUT_MONO));
+  test_stream_ = CreateStream(CHANNEL_LAYOUT_MONO);
   EXPECT_EQ(AlsaPcmOutputStream::kCreated, test_stream_->state());
 
   // Should support multi-channel.
-  test_stream_.reset(CreateStream(CHANNEL_LAYOUT_SURROUND));
+  test_stream_ = CreateStream(CHANNEL_LAYOUT_SURROUND);
   EXPECT_EQ(AlsaPcmOutputStream::kCreated, test_stream_->state());
 
   // Bad bits per sample.
   AudioParameters bad_bps_params(kTestFormat, kTestChannelLayout,
                                  kTestSampleRate, kTestBitsPerSample - 1,
                                  kTestFramesPerPacket);
-  test_stream_.reset(new AlsaPcmOutputStream(kTestDeviceName,
-                                             bad_bps_params,
-                                             &mock_alsa_wrapper_,
-                                             mock_manager_.get()));
+  test_stream_ = new AlsaPcmOutputStream(kTestDeviceName,
+                                         bad_bps_params,
+                                         &mock_alsa_wrapper_,
+                                         mock_manager_.get());
   EXPECT_EQ(AlsaPcmOutputStream::kInError, test_stream_->state());
 
   // Bad format.
   AudioParameters bad_format_params(
       AudioParameters::AUDIO_LAST_FORMAT, kTestChannelLayout, kTestSampleRate,
       kTestBitsPerSample, kTestFramesPerPacket);
-  test_stream_.reset(new AlsaPcmOutputStream(kTestDeviceName,
-                                             bad_format_params,
-                                             &mock_alsa_wrapper_,
-                                             mock_manager_.get()));
+  test_stream_ = new AlsaPcmOutputStream(kTestDeviceName,
+                                         bad_format_params,
+                                         &mock_alsa_wrapper_,
+                                         mock_manager_.get());
   EXPECT_EQ(AlsaPcmOutputStream::kInError, test_stream_->state());
 }
 
 TEST_F(AlsaPcmOutputStreamTest, LatencyFloor) {
   const double kMicrosPerFrame =
       static_cast<double>(1000000) / kTestSampleRate;
   const double kPacketFramesInMinLatency =
       AlsaPcmOutputStream::kMinLatencyMicros / kMicrosPerFrame / 2.0;
 
   // Test that packets which would cause a latency under less than
   // AlsaPcmOutputStream::kMinLatencyMicros will get clipped to
   // AlsaPcmOutputStream::kMinLatencyMicros,
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, _, _, _))
       .WillOnce(DoAll(SetArgumentPointee<0>(kFakeHandle),
                       Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_,
               PcmSetParams(_, _, _, _, _, _,
                            AlsaPcmOutputStream::kMinLatencyMicros))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmGetParams(_, _, _))
       .WillOnce(DoAll(SetArgumentPointee<1>(kTestFramesPerPacket),
                       SetArgumentPointee<2>(kTestFramesPerPacket / 2),
                       Return(0)));
 
-  test_stream_.reset(CreateStream(kTestChannelLayout,
-                                  kPacketFramesInMinLatency));
+  test_stream_ = CreateStream(kTestChannelLayout, kPacketFramesInMinLatency);
   ASSERT_TRUE(test_stream_->Open());
 
   // Now close it and test that everything was released.
   EXPECT_CALL(mock_alsa_wrapper_, PcmClose(kFakeHandle)).WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmName(kFakeHandle))
       .WillOnce(Return(kTestDeviceName));
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   test_stream_->Close();
 
   Mock::VerifyAndClear(&mock_alsa_wrapper_);
   Mock::VerifyAndClear(mock_manager_.get());
 
   // Test that having more packets ends up with a latency based on packet size.
   const int kOverMinLatencyPacketSize = kPacketFramesInMinLatency + 1;
   int64 expected_micros = 2 * AlsaPcmOutputStream::FramesToMicros(
       kOverMinLatencyPacketSize, kTestSampleRate);
 
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, _, _, _))
       .WillOnce(DoAll(SetArgumentPointee<0>(kFakeHandle), Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_,
               PcmSetParams(_, _, _, _, _, _, expected_micros))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmGetParams(_, _, _))
       .WillOnce(DoAll(SetArgumentPointee<1>(kTestFramesPerPacket),
                       SetArgumentPointee<2>(kTestFramesPerPacket / 2),
                       Return(0)));
 
-  test_stream_.reset(CreateStream(kTestChannelLayout,
-                                  kOverMinLatencyPacketSize));
+  test_stream_ = CreateStream(kTestChannelLayout, kOverMinLatencyPacketSize);
   ASSERT_TRUE(test_stream_->Open());
 
   // Now close it and test that everything was released.
   EXPECT_CALL(mock_alsa_wrapper_, PcmClose(kFakeHandle))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmName(kFakeHandle))
       .WillOnce(Return(kTestDeviceName));
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   test_stream_->Close();
 
   Mock::VerifyAndClear(&mock_alsa_wrapper_);
   Mock::VerifyAndClear(mock_manager_.get());
 }
 
 TEST_F(AlsaPcmOutputStreamTest, OpenClose) {
   int64 expected_micros = 2 *
       AlsaPcmOutputStream::FramesToMicros(kTestPacketSize / kTestBytesPerFrame,
                                           kTestSampleRate);
@@ skipping 27 matching lines @@
   EXPECT_EQ(kFakeHandle, test_stream_->playback_handle_);
   EXPECT_EQ(kTestFramesPerPacket, test_stream_->frames_per_packet_);
   EXPECT_TRUE(test_stream_->buffer_.get());
   EXPECT_FALSE(test_stream_->stop_stream_);
 
   // Now close it and test that everything was released.
   EXPECT_CALL(mock_alsa_wrapper_, PcmClose(kFakeHandle))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmName(kFakeHandle))
       .WillOnce(Return(kTestDeviceName));
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   test_stream_->Close();
-
-  EXPECT_TRUE(test_stream_->playback_handle_ == NULL);
-  EXPECT_FALSE(test_stream_->buffer_.get());
-  EXPECT_TRUE(test_stream_->stop_stream_);
 }
 
 TEST_F(AlsaPcmOutputStreamTest, PcmOpenFailed) {
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, _, _, _))
       .WillOnce(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_, StrError(kTestFailedErrno))
       .WillOnce(Return(kDummyMessage));
 
   ASSERT_FALSE(test_stream_->Open());
   ASSERT_EQ(AlsaPcmOutputStream::kInError, test_stream_->state());
 
   // Ensure internal state is set for a no-op stream if PcmOpen() failes.
   EXPECT_TRUE(test_stream_->stop_stream_);
   EXPECT_TRUE(test_stream_->playback_handle_ == NULL);
   EXPECT_FALSE(test_stream_->buffer_.get());
 
   // Close the stream since we opened it to make destruction happy.
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   test_stream_->Close();
 }
 
 TEST_F(AlsaPcmOutputStreamTest, PcmSetParamsFailed) {
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, _, _, _))
       .WillOnce(DoAll(SetArgumentPointee<0>(kFakeHandle),
                       Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_, PcmSetParams(_, _, _, _, _, _, _))
       .WillOnce(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_, PcmClose(kFakeHandle))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmName(kFakeHandle))
       .WillOnce(Return(kTestDeviceName));
   EXPECT_CALL(mock_alsa_wrapper_, StrError(kTestFailedErrno))
       .WillOnce(Return(kDummyMessage));
 
   // If open fails, the stream stays in kCreated because it has effectively had
   // no changes.
   ASSERT_FALSE(test_stream_->Open());
   EXPECT_EQ(AlsaPcmOutputStream::kInError, test_stream_->state());
 
   // Ensure internal state is set for a no-op stream if PcmSetParams() failes.
   EXPECT_TRUE(test_stream_->stop_stream_);
   EXPECT_TRUE(test_stream_->playback_handle_ == NULL);
   EXPECT_FALSE(test_stream_->buffer_.get());
 
   // Close the stream since we opened it to make destruction happy.
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   test_stream_->Close();
 }
 
 TEST_F(AlsaPcmOutputStreamTest, StartStop) {
   // Open() call opens the playback device, sets the parameters, posts a task
   // with the resulting configuration data, and transitions the object state to
   // kIsOpened.
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, _, _, _))
       .WillOnce(DoAll(SetArgumentPointee<0>(kFakeHandle),
                       Return(0)));
@@ skipping 15 matching lines @@
 
   // Expect the pre-roll.
   MockAudioSourceCallback mock_callback;
   EXPECT_CALL(mock_alsa_wrapper_, PcmState(kFakeHandle))
       .Times(3)
       .WillRepeatedly(Return(SND_PCM_STATE_RUNNING));
   EXPECT_CALL(mock_alsa_wrapper_, PcmDelay(kFakeHandle, _))
       .Times(2)
       .WillRepeatedly(DoAll(SetArgumentPointee<1>(0), Return(0)));
   EXPECT_CALL(mock_callback,
-              OnMoreData(test_stream_.get(), _, kTestPacketSize, _))
+              OnMoreData(test_stream_, _, kTestPacketSize, _))
       .Times(2)
       .WillOnce(Return(kTestPacketSize))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmWritei(kFakeHandle, _, _))
       .WillOnce(Return(kTestFramesPerPacket));
 
   // Expect scheduling.
   EXPECT_CALL(mock_alsa_wrapper_, PcmAvailUpdate(kFakeHandle))
       .Times(AtLeast(3))
       .WillOnce(Return(kTestFramesPerPacket))  // Buffer is empty.
       .WillOnce(Return(kTestFramesPerPacket))
       .WillRepeatedly(DoAll(InvokeWithoutArgs(&message_loop_,
                                               &MessageLoop::QuitNow),
                                               Return(0)));  // Buffer is full.
 
   test_stream_->Start(&mock_callback);
   message_loop_.RunAllPending();
 
-  EXPECT_CALL(mock_manager(), ReleaseOutputStream(test_stream_.get()));
   EXPECT_CALL(mock_alsa_wrapper_, PcmClose(kFakeHandle))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, PcmName(kFakeHandle))
       .WillOnce(Return(kTestDeviceName));
   test_stream_->Close();
 }
 
 TEST_F(AlsaPcmOutputStreamTest, WritePacket_FinishedPacket) {
   InitBuffer();
 
@@ skipping 71 matching lines @@
   MockAudioSourceCallback mock_callback;
   EXPECT_CALL(mock_alsa_wrapper_, PcmState(_))
       .WillOnce(Return(SND_PCM_STATE_RUNNING));
   EXPECT_CALL(mock_alsa_wrapper_, PcmDelay(_, _))
       .WillOnce(DoAll(SetArgumentPointee<1>(1), Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_, PcmAvailUpdate(_))
       .WillRepeatedly(Return(0));  // Buffer is full.
 
   // Return a partially filled packet.
   EXPECT_CALL(mock_callback,
-              OnMoreData(test_stream_.get(), _, _, _))
+              OnMoreData(test_stream_, _, _, _))
       .WillOnce(Return(10));
 
   bool source_exhausted;
   test_stream_->set_source_callback(&mock_callback);
   test_stream_->packet_size_ = kTestPacketSize;
   test_stream_->BufferPacket(&source_exhausted);
 
   EXPECT_EQ(10u, test_stream_->buffer_->forward_bytes());
   EXPECT_FALSE(source_exhausted);
 }
 
 TEST_F(AlsaPcmOutputStreamTest, BufferPacket_Negative) {
   InitBuffer();
   test_stream_->buffer_->Clear();
 
   // Simulate where the underrun has occurred right after checking the delay.
   MockAudioSourceCallback mock_callback;
   EXPECT_CALL(mock_alsa_wrapper_, PcmState(_))
       .WillOnce(Return(SND_PCM_STATE_RUNNING));
   EXPECT_CALL(mock_alsa_wrapper_, PcmDelay(_, _))
       .WillOnce(DoAll(SetArgumentPointee<1>(-1), Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_, PcmAvailUpdate(_))
       .WillRepeatedly(Return(0));  // Buffer is full.
   EXPECT_CALL(mock_callback,
-              OnMoreData(test_stream_.get(), _, _, _))
+              OnMoreData(test_stream_, _, _, _))
       .WillOnce(Return(10));
 
   bool source_exhausted;
   test_stream_->set_source_callback(&mock_callback);
   test_stream_->packet_size_ = kTestPacketSize;
   test_stream_->BufferPacket(&source_exhausted);
 
   EXPECT_EQ(10u, test_stream_->buffer_->forward_bytes());
   EXPECT_FALSE(source_exhausted);
 }
 
 TEST_F(AlsaPcmOutputStreamTest, BufferPacket_Underrun) {
   InitBuffer();
   test_stream_->buffer_->Clear();
 
   // If ALSA has underrun then we should assume a delay of zero.
   MockAudioSourceCallback mock_callback;
   EXPECT_CALL(mock_alsa_wrapper_, PcmState(_))
      .WillOnce(Return(SND_PCM_STATE_XRUN));
   EXPECT_CALL(mock_alsa_wrapper_, PcmAvailUpdate(_))
       .WillRepeatedly(Return(0));  // Buffer is full.
   EXPECT_CALL(mock_callback,
-              OnMoreData(test_stream_.get(), _, _, AllOf(
+              OnMoreData(test_stream_, _, _, AllOf(
                   Field(&AudioBuffersState::pending_bytes, 0),
                   Field(&AudioBuffersState::hardware_delay_bytes, 0))))
       .WillOnce(Return(10));
 
   bool source_exhausted;
   test_stream_->set_source_callback(&mock_callback);
   test_stream_->packet_size_ = kTestPacketSize;
   test_stream_->BufferPacket(&source_exhausted);
 
   EXPECT_EQ(10u, test_stream_->buffer_->forward_bytes());
@@ skipping 62 matching lines @@
                 PcmSetParams(kFakeHandle, _, _, i, _, _, _))
         .WillOnce(Return(0));
 
     // The parameters are specified by ALSA documentation, and are in constants
     // in the implementation files.
     EXPECT_CALL(mock_alsa_wrapper_, DeviceNameGetHint(_, StrEq("IOID")))
         .WillRepeatedly(Invoke(OutputHint));
     EXPECT_CALL(mock_alsa_wrapper_, DeviceNameGetHint(_, StrEq("NAME")))
         .WillRepeatedly(Invoke(EchoHint));
 
-    test_stream_.reset(CreateStream(kExpectedLayouts[i]));
+    test_stream_ = CreateStream(kExpectedLayouts[i]);
     EXPECT_TRUE(test_stream_->AutoSelectDevice(i));
     EXPECT_EQ(kExpectedDownmix[i], test_stream_->should_downmix_);
 
     Mock::VerifyAndClearExpectations(&mock_alsa_wrapper_);
     Mock::VerifyAndClearExpectations(mock_manager_.get());
   }
 }
 
 TEST_F(AlsaPcmOutputStreamTest, AutoSelectDevice_FallbackDevices) {
   using std::string;
@@ skipping 29 matching lines @@
   InSequence s;
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, StrEq(first_try.c_str()), _, _))
       .WillOnce(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, StrEq(second_try.c_str()), _, _))
       .WillOnce(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, StrEq(third_try.c_str()), _, _))
       .WillOnce(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_, PcmOpen(_, StrEq(fourth_try.c_str()), _, _))
       .WillOnce(Return(kTestFailedErrno));
 
-  test_stream_.reset(CreateStream(CHANNEL_LAYOUT_5POINT0));
+  test_stream_ = CreateStream(CHANNEL_LAYOUT_5POINT0);
   EXPECT_FALSE(test_stream_->AutoSelectDevice(5));
 }
 
 TEST_F(AlsaPcmOutputStreamTest, AutoSelectDevice_HintFail) {
   // Should get |kDefaultDevice|, and force a 2-channel downmix on a failure to
   // enumerate devices.
   EXPECT_CALL(mock_alsa_wrapper_, DeviceNameHint(_, _, _))
       .WillRepeatedly(Return(kTestFailedErrno));
   EXPECT_CALL(mock_alsa_wrapper_,
               PcmOpen(_, StrEq(AlsaPcmOutputStream::kDefaultDevice), _, _))
       .WillOnce(DoAll(SetArgumentPointee<0>(kFakeHandle), Return(0)));
   EXPECT_CALL(mock_alsa_wrapper_,
               PcmSetParams(kFakeHandle, _, _, 2, _, _, _))
       .WillOnce(Return(0));
   EXPECT_CALL(mock_alsa_wrapper_, StrError(kTestFailedErrno))
       .WillOnce(Return(kDummyMessage));
 
-  test_stream_.reset(CreateStream(CHANNEL_LAYOUT_5POINT0));
+  test_stream_ = CreateStream(CHANNEL_LAYOUT_5POINT0);
   EXPECT_TRUE(test_stream_->AutoSelectDevice(5));
   EXPECT_TRUE(test_stream_->should_downmix_);
 }
 
 TEST_F(AlsaPcmOutputStreamTest, BufferPacket_StopStream) {
   InitBuffer();
   test_stream_->stop_stream_ = true;
   bool source_exhausted;
   test_stream_->BufferPacket(&source_exhausted);
   EXPECT_EQ(0u, test_stream_->buffer_->forward_bytes());
@@ skipping 29 matching lines @@
 
   test_stream_->stop_stream_ = true;
   test_stream_->ScheduleNextWrite(true);
 
   // TODO(ajwong): Find a way to test whether or not another task has been
   // posted so we can verify that the Alsa code will indeed break the task
   // posting loop.
 
   test_stream_->TransitionTo(AlsaPcmOutputStream::kIsClosed);
 }