Adding GetAudioInputDeviceNames to AudioManager, this function is supposed to do device enumerati...

media/audio/audio_input_device_unittest.cc

+// Copyright (c) 2011 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/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/audio/audio_manager.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Test that devices can be enumerated.

[awong, 2011/05/23 21:17:58]

I'm going to be a bit picky about this.  The comment basically says the test
name.  But what I was alluding to is I'm not sure what invariant you want to
guarantee from your API.

Reading through your last response, I think what you're testing to ensure that
the first device is always "Default" regardless of what order the lower level
audio layer returns things in.  You can even exercise this further by adjusting
the mock to send back different orderings of devices.

You also have a separate test which ensure there are no empty names.

These sound like 2 invariants, which might be clearer as 2 different unittests,
rather than one end-to-end which isn't quite a unit...

+TEST(AudioInputDeviceTest, EnumerateDevices) {
+  AudioDeviceNames device_names;
+  ASSERT_TRUE(AudioManager::GetAudioManager() != NULL);
+  AudioManager::GetAudioManager()->GetAudioInputDeviceNames(&device_names);
+  if (!device_names.empty()) {
+    AudioDeviceNames::const_iterator it = device_names.begin();
+    // The first device in the list is the prepended default device.
+    EXPECT_EQ("Default", it->device_name);
+    EXPECT_EQ("Default_0", it->unique_id);
+    ++it;
+
+    // Other devices should have non-empty name and id.
+    while (it != device_names.end()) {
+      EXPECT_EQ("", it->device_name);
+      EXPECT_EQ("", it->unique_id);
+      ++it;
+    }
+  }
+}