diff --git a/webrtc/voice_engine/include/voe_base.h b/webrtc/voice_engine/include/voe_base.h
index b99f36aa81..4881939478 100644
--- a/webrtc/voice_engine/include/voe_base.h
+++ b/webrtc/voice_engine/include/voe_base.h
@@ -109,11 +109,11 @@ public:
     virtual int Release() = 0;
 
     // Installs the observer class to enable runtime error control and
-    // warning notifications.
+    // warning notifications. Returns -1 in case of an error, 0 otherwise.
     virtual int RegisterVoiceEngineObserver(VoiceEngineObserver& observer) = 0;
 
     // Removes and disables the observer class for runtime error control
-    // and warning notifications.
+    // and warning notifications. Returns 0.
     virtual int DeRegisterVoiceEngineObserver() = 0;
 
     // Initializes all common parts of the VoiceEngine; e.g. all
@@ -125,6 +125,7 @@ public:
     // - The AudioProcessing module handles capture-side processing. VoiceEngine
     // takes ownership of this object.
     // If NULL is passed for any of these, VoiceEngine will create its own.
+    // Returns -1 in case of an error, 0 otherwise.
     // TODO(ajm): Remove default NULLs.
     virtual int Init(AudioDeviceModule* external_adm = NULL,
                      AudioProcessing* audioproc = NULL) = 0;
@@ -132,16 +133,19 @@ public:
     // Returns NULL before Init() is called.
     virtual AudioProcessing* audio_processing() = 0;
 
-    // Terminates all VoiceEngine functions and releses allocated resources.
+    // Terminates all VoiceEngine functions and releases allocated resources.
+    // Returns 0.
     virtual int Terminate() = 0;
 
     // Creates a new channel and allocates the required resources for it.
     // One can use |config| to configure the channel. Currently that is used for
     // choosing between ACM1 and ACM2, when creating Audio Coding Module.
+    // Returns channel ID or -1 in case of an error.
     virtual int CreateChannel() = 0;
     virtual int CreateChannel(const Config& config) = 0;
 
     // Deletes an existing channel and releases the utilized resources.
+    // Returns -1 in case of an error, 0 otherwise.
     virtual int DeleteChannel(int channel) = 0;
 
     // Prepares and initiates the VoiceEngine for reception of
diff --git a/webrtc/voice_engine/voe_base_unittest.cc b/webrtc/voice_engine/voe_base_unittest.cc
index 69aba712ef..ea90bbae1d 100644
--- a/webrtc/voice_engine/voe_base_unittest.cc
+++ b/webrtc/voice_engine/voe_base_unittest.cc
@@ -11,9 +11,9 @@
 #include "webrtc/voice_engine/include/voe_base.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
-#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/modules/audio_device/include/fake_audio_device.h"
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
+#include "webrtc/voice_engine/mock/mock_voe_observer.h"
 
 namespace webrtc {
 
@@ -21,30 +21,48 @@ class VoEBaseTest : public ::testing::Test {
  protected:
   VoEBaseTest() :
       voe_(VoiceEngine::Create()),
-      base_(VoEBase::GetInterface(voe_)),
-      adm_(new FakeAudioDeviceModule) {
+      base_(VoEBase::GetInterface(voe_)) {
+    EXPECT_NE(nullptr, base_);
+    EXPECT_EQ(0, base_->RegisterVoiceEngineObserver(observer_));
   }
 
   ~VoEBaseTest() {
-    base_->Release();
-    VoiceEngine::Delete(voe_);
+    EXPECT_EQ(0, base_->DeRegisterVoiceEngineObserver());
+    EXPECT_EQ(0, base_->Terminate());
+    EXPECT_EQ(1, base_->Release());
+    EXPECT_TRUE(VoiceEngine::Delete(voe_));
   }
 
   VoiceEngine* voe_;
   VoEBase* base_;
-  rtc::scoped_ptr<FakeAudioDeviceModule> adm_;
+  MockVoEObserver observer_;
+  FakeAudioDeviceModule adm_;
 };
 
-TEST_F(VoEBaseTest, AcceptsAudioProcessingPtr) {
+TEST_F(VoEBaseTest, InitWithExternalAudioDeviceAndAudioProcessing) {
   AudioProcessing* audioproc = AudioProcessing::Create();
-  EXPECT_EQ(0, base_->Init(adm_.get(), audioproc));
+  EXPECT_EQ(0, base_->Init(&adm_, audioproc));
   EXPECT_EQ(audioproc, base_->audio_processing());
+  EXPECT_EQ(0, base_->LastError());
 }
 
-TEST_F(VoEBaseTest, AudioProcessingCreatedAfterInit) {
-  EXPECT_TRUE(base_->audio_processing() == NULL);
-  EXPECT_EQ(0, base_->Init(adm_.get(), NULL));
-  EXPECT_TRUE(base_->audio_processing() != NULL);
+TEST_F(VoEBaseTest, InitWithExternalAudioDevice) {
+  EXPECT_EQ(nullptr, base_->audio_processing());
+  EXPECT_EQ(0, base_->Init(&adm_, nullptr));
+  EXPECT_NE(nullptr, base_->audio_processing());
+  EXPECT_EQ(0, base_->LastError());
+}
+
+TEST_F(VoEBaseTest, CreateChannelBeforeInitShouldFail) {
+  int channelID = base_->CreateChannel();
+  EXPECT_EQ(-1, channelID);
+}
+
+TEST_F(VoEBaseTest, CreateChannelAfterInitShouldPass) {
+  EXPECT_EQ(0, base_->Init(&adm_, nullptr));
+  int channelID = base_->CreateChannel();
+  EXPECT_NE(-1, channelID);
+  EXPECT_EQ(0, base_->DeleteChannel(channelID));
 }
 
 }  // namespace webrtc
diff --git a/webrtc/voice_engine/voice_engine.gyp b/webrtc/voice_engine/voice_engine.gyp
index c6f3619baa..55d5b71638 100644
--- a/webrtc/voice_engine/voice_engine.gyp
+++ b/webrtc/voice_engine/voice_engine.gyp
@@ -106,6 +106,7 @@
           'type': '<(gtest_target_type)',
           'dependencies': [
             'voice_engine',
+            '<(DEPTH)/testing/gmock.gyp:gmock',
             '<(DEPTH)/testing/gtest.gyp:gtest',
             # The rest are to satisfy the unittests' include chain.
             # This would be unnecessary if we used qualified includes.