Adds support for capture device enumeration on Windows.

media/audio/audio_input_device_unittest.cc

Index: media/audio/audio_input_device_unittest.cc
===================================================================
--- media/audio/audio_input_device_unittest.cc	(revision 111497)
+++ media/audio/audio_input_device_unittest.cc	(working copy)
@@ -2,32 +2,145 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/environment.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/win/scoped_com_initializer.h"
+#include "media/audio/audio_manager.h"
 #include "media/audio/audio_manager_base.h"
+#if defined(OS_WIN)
+#include "media/audio/win/audio_manager_win.h"
+#endif
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace media {
+using base::win::ScopedCOMInitializer;
+using media::AudioDeviceNames;
 
-// Test that devices can be enumerated.
-TEST(AudioInputDeviceTest, EnumerateDevices) {
-  AudioDeviceNames device_names;
-  ASSERT_TRUE(AudioManager::GetAudioManager() != NULL);
-  AudioManager::GetAudioManager()->GetAudioInputDeviceNames(
-      &device_names);
+// Test fixture which allows us to override the default enumeration API on
+// Windows.
+class AudioInputDeviceTest
+    : public ::testing::Test {
+ protected:
+#if defined(OS_WIN)
+  // Store current device-enumeration type to ensure that it can be restored
+  // after last test in this test suite.
+  static void SetUpTestCase() {
+    enumeration_type_ = static_cast<AudioManagerWin*>(
+        AudioManager::GetAudioManager())->enumeration_type();
+  }
+
+  // Restore pre-test state of device-enumeration type.
+  static void TearDownTestCase() {
+    static_cast<AudioManagerWin*>(
+      AudioManager::GetAudioManager())->SetEnumerationType(enumeration_type_);
+  }
+
+  bool SetMMDeviceEnumeration(AudioManager* audio_manager) {
+    AudioManagerWin* amw = static_cast<AudioManagerWin*>(audio_manager);
+    // Windows Wave is used as default if Windows XP was detected =>
+    // return false since MMDevice is not supported on XP.
+    if (amw->enumeration_type() == AudioManagerWin::kWaveEnumeration)
+      return false;
+
+    amw->SetEnumerationType(AudioManagerWin::kMMDeviceEnumeration);
+    return true;
+  }
+
+  void SetWaveEnumeration(AudioManager* audio_manager) {
+    AudioManagerWin* amw = static_cast<AudioManagerWin*>(audio_manager);
+    amw->SetEnumerationType(AudioManagerWin::kWaveEnumeration);
+  }
+
+  // Stores the pre-test state representing the device-enumeration type.
+  static AudioManagerWin::EnumerationType enumeration_type_;
+#endif
+};
+
+#if defined(OS_WIN)
+AudioManagerWin::EnumerationType AudioInputDeviceTest::enumeration_type_ =
+    AudioManagerWin::kUninitializedEnumeration;
+#endif
+
+// Convenience method which ensures that we are not running on the build
+// bots which lacks audio device support.
+static bool CanRunAudioTests() {
+  scoped_ptr<base::Environment> env(base::Environment::Create());
+  if (env->HasVar("CHROME_HEADLESS"))
+    return false;
+  return true;
+}
+
+// Helper method which verifies that the device list starts with a valid
+// default record followed by non-default device names.
+static void CheckDeviceNames(const AudioDeviceNames& device_names) {
   if (!device_names.empty()) {
     AudioDeviceNames::const_iterator it = device_names.begin();
-    // The first device in the list is the prepended default device.
+
+    // The first device in the list should always be the default device.
     EXPECT_EQ(std::string(AudioManagerBase::kDefaultDeviceName),
-              it->device_name);
+      it->device_name);
     EXPECT_EQ(std::string(AudioManagerBase::kDefaultDeviceId), it->unique_id);
     ++it;
 
-    // Other devices should have non-empty name and id.
+    // Other devices should have non-empty name and id and should not contain
+    // default name or id.
     while (it != device_names.end()) {
-      EXPECT_NE("", it->device_name);
-      EXPECT_NE("", it->unique_id);
+      EXPECT_FALSE(it->device_name.empty());
+      EXPECT_FALSE(it->unique_id.empty());
+      EXPECT_NE(std::string(AudioManagerBase::kDefaultDeviceName),
+                it->device_name);
+      EXPECT_NE(std::string(AudioManagerBase::kDefaultDeviceId),
+                it->unique_id);
       ++it;
     }
   }
 }
 
-}  // namespace media
+// Test that devices can be enumerated.
+TEST_F(AudioInputDeviceTest, EnumerateDevices) {
+  if (!CanRunAudioTests())
+    return;
+  // The MMDevice API requires a correct COM environment.
+  ScopedCOMInitializer com_init(ScopedCOMInitializer::kMTA);
+  AudioDeviceNames device_names;
+  AudioManager* audio_man = AudioManager::GetAudioManager();
+  EXPECT_TRUE(audio_man != NULL);
+  audio_man->GetAudioInputDeviceNames(&device_names);
+  CheckDeviceNames(device_names);
+}
+
+// Run additional tests for Windows since enumeration can be done using
+// two different APIs. MMDevice is default for Vista and higher and Wave
+// is default for XP and lower.
+#if defined(OS_WIN)
+
+// Override default enumeration API and force usage of Windows MMDevice.
+// This test will only run on Windows Vista and higher.
+TEST_F(AudioInputDeviceTest, EnumerateDevicesWinMMDevice) {
+  if (!CanRunAudioTests())
+    return;
+  // The MMDevice API requires a correct COM environment.
+  ScopedCOMInitializer com_init(ScopedCOMInitializer::kMTA);
+  AudioDeviceNames device_names;
+  AudioManager* audio_man = AudioManager::GetAudioManager();
+  if (!SetMMDeviceEnumeration(audio_man)) {
+    // Usage of MMDevice will fail on XP and lower.
+    return;
+  }
+  audio_man->GetAudioInputDeviceNames(&device_names);
+  CheckDeviceNames(device_names);
+}
+
+// Override default enumeration API and force usage of Windows Wave.
+// This test will run on Windows XP, Windows Vista and Windows 7.
+TEST_F(AudioInputDeviceTest, EnumerateDevicesWinWave) {
+  if (!CanRunAudioTests())
+    return;
+  AudioDeviceNames device_names;
+  AudioManager* audio_man = AudioManager::GetAudioManager();
+  EXPECT_TRUE(audio_man != NULL);
+  SetWaveEnumeration(audio_man);
+  audio_man->GetAudioInputDeviceNames(&device_names);
+  CheckDeviceNames(device_names);
+}
+
+#endif