AudioService: better A2DP (dis)connection testing

  A sequence of A2DP connection / disconnection / connection was
supposed to be covered by a unit test in AudioDeviceBrokerTest
with different timings. But if the test was run in the absence
of background media playback, the disconnection event was not
delayed by 1s after sending the BECOMING_NOISY event, and the
connection / disconn / connection sequence was executed in the
same order as the sender used, causing the test to succeed.
  This CL adds functionality in the adapter for AudioSystem to
configure whether it is to simulate playback or not, so all
tests can be run with and without.

Also:
- update system server adapter to support BECOMING_NOISY intent
  and make AudioDeviceBroker use the adapter code instead.
- move the "no op" code of the adapters from the server folder
 (where it doesn't belong) to the test folder (because it should
 only ever be used in the context of a test).

Bug: 142293357
Test: atest AudioDeviceBrokerTest
Change-Id: Ic9877b5cbff97930bfc4bc1e48fee07d96799a86

8 files changed, 264 insertions, 148 deletions

diff --git a/services/core/java/com/android/server/audio/AudioDeviceBroker.java b/services/core/java/com/android/server/audio/AudioDeviceBroker.java
index 032ad63a8570..6067ccb2da27 100644
--- a/services/core/java/com/android/server/audio/AudioDeviceBroker.java
+++ b/services/core/java/com/android/server/audio/AudioDeviceBroker.java
@@ -25,7 +25,6 @@ import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.media.AudioDeviceAttributes;
-import android.media.AudioManager;
 import android.media.AudioRoutesInfo;
 import android.media.AudioSystem;
 import android.media.IAudioRoutesObserver;
@@ -38,7 +37,6 @@ import android.os.Looper;
 import android.os.Message;
 import android.os.PowerManager;
 import android.os.SystemClock;
-import android.os.UserHandle;
 import android.util.Log;
 import android.util.PrintWriterPrinter;
 
@@ -71,6 +69,8 @@ import java.io.PrintWriter;
     private final AudioDeviceInventory mDeviceInventory;
     // Manages notifications to BT service
     private final BtHelper mBtHelper;
+    // Adapter for system_server-reserved operations
+    private final SystemServerAdapter mSystemServer;
 
 
     //-------------------------------------------------------------------
@@ -97,17 +97,21 @@ import java.io.PrintWriter;
         mAudioService = service;
         mBtHelper = new BtHelper(this);
         mDeviceInventory = new AudioDeviceInventory(this);
+        mSystemServer = SystemServerAdapter.getDefaultAdapter(mContext);
 
         init();
     }
 
-    /** for test purposes only, inject AudioDeviceInventory */
+    /** for test purposes only, inject AudioDeviceInventory and adapter for operations running
+     *  in system_server */
     AudioDeviceBroker(@NonNull Context context, @NonNull AudioService service,
-                      @NonNull AudioDeviceInventory mockDeviceInventory) {
+                      @NonNull AudioDeviceInventory mockDeviceInventory,
+                      @NonNull SystemServerAdapter mockSystemServer) {
         mContext = context;
         mAudioService = service;
         mBtHelper = new BtHelper(this);
         mDeviceInventory = mockDeviceInventory;
+        mSystemServer = mockSystemServer;
 
         init();
     }
@@ -682,7 +686,7 @@ import java.io.PrintWriter;
     private void onSendBecomingNoisyIntent() {
         AudioService.sDeviceLogger.log((new AudioEventLogger.StringEvent(
                 "broadcast ACTION_AUDIO_BECOMING_NOISY")).printLog(TAG));
-        sendBroadcastToAll(new Intent(AudioManager.ACTION_AUDIO_BECOMING_NOISY));
+        mSystemServer.sendDeviceBecomingNoisyIntent();
     }
 
     //---------------------------------------------------------------------
@@ -1100,17 +1104,4 @@ import java.io.PrintWriter;
                     time);
         }
     }
-
-    //-------------------------------------------------------------
-    // internal utilities
-    private void sendBroadcastToAll(Intent intent) {
-        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
-        intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
-        final long ident = Binder.clearCallingIdentity();
-        try {
-            mContext.sendBroadcastAsUser(intent, UserHandle.ALL);
-        } finally {
-            Binder.restoreCallingIdentity(ident);
-        }
-    }
 }
diff --git a/services/core/java/com/android/server/audio/AudioDeviceInventory.java b/services/core/java/com/android/server/audio/AudioDeviceInventory.java
index 3e97a1e136c6..266dfc7e257e 100644
--- a/services/core/java/com/android/server/audio/AudioDeviceInventory.java
+++ b/services/core/java/com/android/server/audio/AudioDeviceInventory.java
@@ -1118,7 +1118,7 @@ public class AudioDeviceInventory {
                 && AudioSystem.isSingleAudioDeviceType(devices, device)
                 && !mDeviceBroker.hasMediaDynamicPolicy()
                 && (musicDevice != AudioSystem.DEVICE_OUT_REMOTE_SUBMIX)) {
-            if (!AudioSystem.isStreamActive(AudioSystem.STREAM_MUSIC, 0 /*not looking in past*/)
+            if (!mAudioSystem.isStreamActive(AudioSystem.STREAM_MUSIC, 0 /*not looking in past*/)
                     && !mDeviceBroker.hasAudioFocusUsers()) {
                 // no media playback, not a "becoming noisy" situation, otherwise it could cause
                 // the pausing of some apps that are playing remotely
diff --git a/services/core/java/com/android/server/audio/AudioSystemAdapter.java b/services/core/java/com/android/server/audio/AudioSystemAdapter.java
index 40c13904fbc9..e60243fc481c 100644
--- a/services/core/java/com/android/server/audio/AudioSystemAdapter.java
+++ b/services/core/java/com/android/server/audio/AudioSystemAdapter.java
@@ -19,7 +19,6 @@ package com.android.server.audio;
 import android.annotation.NonNull;
 import android.media.AudioDeviceAttributes;
 import android.media.AudioSystem;
-import android.util.Log;
 
 /**
  * Provides an adapter to access functionality of the android.media.AudioSystem class for device
@@ -39,15 +38,6 @@ public class AudioSystemAdapter {
     }
 
     /**
-     * Create an adapter for AudioSystem that always succeeds, and does nothing.
-     * Overridden methods can be configured
-     * @return a no-op AudioSystem adapter with configurable adapter
-     */
-    static final @NonNull AudioSystemAdapter getConfigurableAdapter() {
-        return new AudioSystemConfigurableAdapter();
-    }
-
-    /**
      * Same as {@link AudioSystem#setDeviceConnectionState(int, int, String, String, int)}
      * @param device
      * @param state
@@ -143,75 +133,10 @@ public class AudioSystemAdapter {
         return AudioSystem.setCurrentImeUid(uid);
     }
 
-    //--------------------------------------------------------------------
-    protected static class AudioSystemConfigurableAdapter extends AudioSystemAdapter {
-        private static final String TAG = "ASA";
-        private boolean mIsMicMuted = false;
-        private boolean mMuteMicrophoneFails = false;
-
-        public void configureIsMicrophoneMuted(boolean muted) {
-            mIsMicMuted = muted;
-        }
-
-        public void configureMuteMicrophoneToFail(boolean fail) {
-            mMuteMicrophoneFails = fail;
-        }
-
-        //-----------------------------------------------------------------
-        // Overrides of AudioSystemAdapter
-        @Override
-        public int setDeviceConnectionState(int device, int state, String deviceAddress,
-                                            String deviceName, int codecFormat) {
-            Log.i(TAG, String.format("setDeviceConnectionState(0x%s, %s, %s, 0x%s",
-                    Integer.toHexString(device), state, deviceAddress, deviceName,
-                    Integer.toHexString(codecFormat)));
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int getDeviceConnectionState(int device, String deviceAddress) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int handleDeviceConfigChange(int device, String deviceAddress,
-                                                   String deviceName, int codecFormat) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int setPreferredDeviceForStrategy(int strategy,
-                                                 @NonNull AudioDeviceAttributes device) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int removePreferredDeviceForStrategy(int strategy) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int setParameters(String keyValuePairs) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public boolean isMicrophoneMuted() {
-            return mIsMicMuted;
-        }
-
-        @Override
-        public int muteMicrophone(boolean on) {
-            if (mMuteMicrophoneFails) {
-                return AudioSystem.AUDIO_STATUS_ERROR;
-            }
-            mIsMicMuted = on;
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
-
-        @Override
-        public int setCurrentImeUid(int uid) {
-            return AudioSystem.AUDIO_STATUS_OK;
-        }
+    /**
+     * Same as {@link AudioSystem#isStreamActive(int, int)}
+     */
+    public boolean isStreamActive(int stream, int inPastMs) {
+        return AudioSystem.isStreamActive(stream, inPastMs);
     }
 }
diff --git a/services/core/java/com/android/server/audio/SystemServerAdapter.java b/services/core/java/com/android/server/audio/SystemServerAdapter.java
index 509f6be76f17..68893f8ca6c7 100644
--- a/services/core/java/com/android/server/audio/SystemServerAdapter.java
+++ b/services/core/java/com/android/server/audio/SystemServerAdapter.java
@@ -21,8 +21,11 @@ import android.annotation.Nullable;
 import android.content.Context;
 import android.content.Intent;
 import android.media.AudioManager;
+import android.os.Binder;
 import android.os.UserHandle;
 
+import java.util.Objects;
+
 /**
  * Provides an adapter to access functionality reserved to components running in system_server
  * Functionality such as sending privileged broadcasts is to be accessed through the default
@@ -32,7 +35,7 @@ public class SystemServerAdapter {
 
     protected final Context mContext;
 
-    private SystemServerAdapter(@Nullable Context context) {
+    protected SystemServerAdapter(@Nullable Context context) {
         mContext = context;
     }
     /**
@@ -40,19 +43,11 @@ public class SystemServerAdapter {
      * @return the adapter
      */
     static final @NonNull SystemServerAdapter getDefaultAdapter(Context context) {
+        Objects.requireNonNull(context);
         return new SystemServerAdapter(context);
     }
 
     /**
-     * Create an adapter that does nothing.
-     * Use for running non-privileged tests, such as unit tests
-     * @return a no-op adapter
-     */
-    static final @NonNull SystemServerAdapter getNoOpAdapter() {
-        return new NoOpSystemServerAdapter();
-    }
-
-    /**
      * @return true if this is supposed to be run in system_server, false otherwise (e.g. for a
      *     unit test)
      */
@@ -70,21 +65,21 @@ public class SystemServerAdapter {
                 UserHandle.ALL);
     }
 
-    //--------------------------------------------------------------------
-    protected static class NoOpSystemServerAdapter extends SystemServerAdapter {
-
-        NoOpSystemServerAdapter() {
-            super(null);
-        }
-
-        @Override
-        public boolean isPrivileged() {
-            return false;
+    /**
+     * Broadcast ACTION_AUDIO_BECOMING_NOISY
+     */
+    public void sendDeviceBecomingNoisyIntent() {
+        if (mContext == null) {
+            return;
         }
-
-        @Override
-        public void sendMicrophoneMuteChangedIntent() {
-            // no-op
+        final Intent intent = new Intent(AudioManager.ACTION_AUDIO_BECOMING_NOISY);
+        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
+        final long ident = Binder.clearCallingIdentity();
+        try {
+            mContext.sendBroadcastAsUser(intent, UserHandle.ALL);
+        } finally {
+            Binder.restoreCallingIdentity(ident);
         }
     }
 }
diff --git a/services/tests/servicestests/src/com/android/server/audio/AudioDeviceBrokerTest.java b/services/tests/servicestests/src/com/android/server/audio/AudioDeviceBrokerTest.java
index 22f8b9c8ae92..4ecaac55ce96 100644
--- a/services/tests/servicestests/src/com/android/server/audio/AudioDeviceBrokerTest.java
+++ b/services/tests/servicestests/src/com/android/server/audio/AudioDeviceBrokerTest.java
@@ -58,6 +58,7 @@ public class AudioDeviceBrokerTest {
     @Mock private AudioService mMockAudioService;
     @Spy private AudioDeviceInventory mSpyDevInventory;
     @Spy private AudioSystemAdapter mSpyAudioSystem;
+    private SystemServerAdapter mSystemServer;
 
     private BluetoothDevice mFakeBtDevice;
 
@@ -66,9 +67,11 @@ public class AudioDeviceBrokerTest {
         mContext = InstrumentationRegistry.getTargetContext();
 
         mMockAudioService = mock(AudioService.class);
-        mSpyAudioSystem = spy(AudioSystemAdapter.getConfigurableAdapter());
+        mSpyAudioSystem = spy(new NoOpAudioSystemAdapter());
         mSpyDevInventory = spy(new AudioDeviceInventory(mSpyAudioSystem));
-        mAudioDeviceBroker = new AudioDeviceBroker(mContext, mMockAudioService, mSpyDevInventory);
+        mSystemServer = new NoOpSystemServerAdapter();
+        mAudioDeviceBroker = new AudioDeviceBroker(mContext, mMockAudioService, mSpyDevInventory,
+                mSystemServer);
         mSpyDevInventory.setDeviceBroker(mAudioDeviceBroker);
 
         BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
@@ -79,8 +82,8 @@ public class AudioDeviceBrokerTest {
     @After
     public void tearDown() throws Exception { }
 
-    @Test
-    public void testSetUpAndTearDown() { }
+//    @Test
+//    public void testSetUpAndTearDown() { }
 
     /**
      * postBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent() for connection:
@@ -90,7 +93,7 @@ public class AudioDeviceBrokerTest {
      */
     @Test
     public void testPostA2dpDeviceConnectionChange() throws Exception {
-        Log.i(TAG, "testPostA2dpDeviceConnectionChange");
+        Log.i(TAG, "starting testPostA2dpDeviceConnectionChange");
         Assert.assertNotNull("invalid null BT device", mFakeBtDevice);
 
         mAudioDeviceBroker.postBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(mFakeBtDevice,
@@ -104,13 +107,8 @@ public class AudioDeviceBrokerTest {
                 ArgumentMatchers.eq(1) /*a2dpVolume*/
         );
 
-        final String expectedName = mFakeBtDevice.getName() == null ? "" : mFakeBtDevice.getName();
-        verify(mSpyAudioSystem, times(1)).setDeviceConnectionState(
-                ArgumentMatchers.eq(AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP),
-                ArgumentMatchers.eq(AudioSystem.DEVICE_STATE_AVAILABLE),
-                ArgumentMatchers.eq(mFakeBtDevice.getAddress()),
-                ArgumentMatchers.eq(expectedName),
-                anyInt() /*codec*/);
+        // verify the connection was reported to AudioSystem
+        checkSingleSystemConnection(mFakeBtDevice);
     }
 
     /**
@@ -121,31 +119,70 @@ public class AudioDeviceBrokerTest {
      */
     @Test
     public void testA2dpDeviceConnectionDisconnectionConnectionChange() throws Exception {
-        Log.i(TAG, "testA2dpDeviceConnectionDisconnectionConnectionChange");
+        Log.i(TAG, "starting testA2dpDeviceConnectionDisconnectionConnectionChange");
 
-        doTestConnectionDisconnectionReconnection(0);
+        doTestConnectionDisconnectionReconnection(0, false,
+                // cannot guarantee single connection since commands are posted in separate thread
+                // than they are processed
+                false);
     }
 
     /**
      * Verify device disconnection and reconnection within the BECOMING_NOISY window
+     * in the absence of media playback
      * @throws Exception
      */
     @Test
     public void testA2dpDeviceReconnectionWithinBecomingNoisyDelay() throws Exception {
-        Log.i(TAG, "testA2dpDeviceReconnectionWithinBecomingNoisyDelay");
+        Log.i(TAG, "starting testA2dpDeviceReconnectionWithinBecomingNoisyDelay");
+
+        doTestConnectionDisconnectionReconnection(AudioService.BECOMING_NOISY_DELAY_MS / 2,
+                false,
+                // do not check single connection since the connection command will come much
+                // after the disconnection command
+                false);
+    }
 
-        doTestConnectionDisconnectionReconnection(AudioService.BECOMING_NOISY_DELAY_MS / 2);
+    /**
+     * Same as testA2dpDeviceConnectionDisconnectionConnectionChange() but with mock media playback
+     * @throws Exception
+     */
+    @Test
+    public void testA2dpConnectionDisconnectionConnectionChange_MediaPlayback() throws Exception {
+        Log.i(TAG, "starting testA2dpConnectionDisconnectionConnectionChange_MediaPlayback");
+
+        doTestConnectionDisconnectionReconnection(0, true,
+                // guarantee single connection since because of media playback the disconnection
+                // is supposed to be delayed, and thus cancelled because of the connection
+                true);
+    }
+
+    /**
+     * Same as testA2dpDeviceReconnectionWithinBecomingNoisyDelay() but with mock media playback
+     * @throws Exception
+     */
+    @Test
+    public void testA2dpReconnectionWithinBecomingNoisyDelay_MediaPlayback() throws Exception {
+        Log.i(TAG, "starting testA2dpReconnectionWithinBecomingNoisyDelay_MediaPlayback");
+
+        doTestConnectionDisconnectionReconnection(AudioService.BECOMING_NOISY_DELAY_MS / 2,
+                true,
+                // guarantee single connection since because of media playback the disconnection
+                // is supposed to be delayed, and thus cancelled because of the connection
+                true);
     }
 
-    private void doTestConnectionDisconnectionReconnection(int delayAfterDisconnection)
-            throws Exception {
+    private void doTestConnectionDisconnectionReconnection(int delayAfterDisconnection,
+            boolean mockMediaPlayback, boolean guaranteeSingleConnection) throws Exception {
         when(mMockAudioService.getDeviceForStream(AudioManager.STREAM_MUSIC))
                 .thenReturn(AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP);
         when(mMockAudioService.isInCommunication()).thenReturn(false);
         when(mMockAudioService.hasMediaDynamicPolicy()).thenReturn(false);
         when(mMockAudioService.hasAudioFocusUsers()).thenReturn(false);
 
-        // first connection
+        ((NoOpAudioSystemAdapter) mSpyAudioSystem).configureIsStreamActive(mockMediaPlayback);
+
+        // first connection: ensure the device is connected as a starting condition for the test
         mAudioDeviceBroker.postBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(mFakeBtDevice,
                 BluetoothProfile.STATE_CONNECTED, BluetoothProfile.A2DP, true, 1);
         Thread.sleep(MAX_MESSAGE_HANDLING_DELAY_MS);
@@ -169,5 +206,26 @@ public class AudioDeviceBrokerTest {
                 ArgumentMatchers.eq(BluetoothProfile.STATE_CONNECTED));
         Assert.assertTrue("Mock device not connected",
                 mSpyDevInventory.isA2dpDeviceConnected(mFakeBtDevice));
+
+        if (guaranteeSingleConnection) {
+            // when the disconnection was expected to be cancelled, there should have been a single
+            //  call to AudioSystem to declare the device connected (available)
+            checkSingleSystemConnection(mFakeBtDevice);
+        }
+    }
+
+    /**
+     * Verifies the given device was reported to AudioSystem exactly once as available
+     * @param btDevice
+     * @throws Exception
+     */
+    private void checkSingleSystemConnection(BluetoothDevice btDevice) throws Exception {
+        final String expectedName = btDevice.getName() == null ? "" : btDevice.getName();
+        verify(mSpyAudioSystem, times(1)).setDeviceConnectionState(
+                ArgumentMatchers.eq(AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP),
+                ArgumentMatchers.eq(AudioSystem.DEVICE_STATE_AVAILABLE),
+                ArgumentMatchers.eq(btDevice.getAddress()),
+                ArgumentMatchers.eq(expectedName),
+                anyInt() /*codec*/);
     }
 }
diff --git a/services/tests/servicestests/src/com/android/server/audio/AudioServiceTest.java b/services/tests/servicestests/src/com/android/server/audio/AudioServiceTest.java
index 6185ae6d93f9..54945fbc2dd2 100644
--- a/services/tests/servicestests/src/com/android/server/audio/AudioServiceTest.java
+++ b/services/tests/servicestests/src/com/android/server/audio/AudioServiceTest.java
@@ -57,8 +57,8 @@ public class AudioServiceTest {
             sLooperPrepared = true;
         }
         mContext = InstrumentationRegistry.getTargetContext();
-        mAudioSystem = AudioSystemAdapter.getConfigurableAdapter();
-        mSpySystemServer = spy(SystemServerAdapter.getNoOpAdapter());
+        mAudioSystem = new NoOpAudioSystemAdapter();
+        mSpySystemServer = spy(new NoOpSystemServerAdapter());
         mAudioService = new AudioService(mContext, mAudioSystem, mSpySystemServer);
     }
 
@@ -70,8 +70,7 @@ public class AudioServiceTest {
     public void testMuteMicrophone() throws Exception {
         Log.i(TAG, "running testMuteMicrophone");
         Assert.assertNotNull(mAudioService);
-        final AudioSystemAdapter.AudioSystemConfigurableAdapter testAudioSystem =
-                (AudioSystemAdapter.AudioSystemConfigurableAdapter) mAudioSystem;
+        final NoOpAudioSystemAdapter testAudioSystem = (NoOpAudioSystemAdapter) mAudioSystem;
         testAudioSystem.configureMuteMicrophoneToFail(false);
         for (boolean muted : new boolean[] { true, false}) {
             testAudioSystem.configureIsMicrophoneMuted(!muted);
@@ -96,8 +95,7 @@ public class AudioServiceTest {
     public void testMuteMicrophoneWhenFail() throws Exception {
         Log.i(TAG, "running testMuteMicrophoneWhenFail");
         Assert.assertNotNull(mAudioService);
-        final AudioSystemAdapter.AudioSystemConfigurableAdapter testAudioSystem =
-                (AudioSystemAdapter.AudioSystemConfigurableAdapter) mAudioSystem;
+        final NoOpAudioSystemAdapter testAudioSystem = (NoOpAudioSystemAdapter) mAudioSystem;
         testAudioSystem.configureMuteMicrophoneToFail(true);
         for (boolean muted : new boolean[] { true, false}) {
             testAudioSystem.configureIsMicrophoneMuted(!muted);
diff --git a/services/tests/servicestests/src/com/android/server/audio/NoOpAudioSystemAdapter.java b/services/tests/servicestests/src/com/android/server/audio/NoOpAudioSystemAdapter.java
new file mode 100644
index 000000000000..a9cef20268f4
--- /dev/null
+++ b/services/tests/servicestests/src/com/android/server/audio/NoOpAudioSystemAdapter.java
@@ -0,0 +1,107 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.audio;
+
+import android.annotation.NonNull;
+import android.media.AudioDeviceAttributes;
+import android.media.AudioSystem;
+import android.util.Log;
+
+/**
+ * Provides an adapter for AudioSystem that does nothing.
+ * Overridden methods can be configured.
+ */
+public class NoOpAudioSystemAdapter extends AudioSystemAdapter {
+    private static final String TAG = "ASA";
+    private boolean mIsMicMuted = false;
+    private boolean mMuteMicrophoneFails = false;
+    private boolean mIsStreamActive = false;
+
+    public void configureIsMicrophoneMuted(boolean muted) {
+        mIsMicMuted = muted;
+    }
+
+    public void configureIsStreamActive(boolean active) {
+        mIsStreamActive = active;
+    }
+
+    public void configureMuteMicrophoneToFail(boolean fail) {
+        mMuteMicrophoneFails = fail;
+    }
+
+    //-----------------------------------------------------------------
+    // Overrides of AudioSystemAdapter
+    @Override
+    public int setDeviceConnectionState(int device, int state, String deviceAddress,
+            String deviceName, int codecFormat) {
+        Log.i(TAG, String.format("setDeviceConnectionState(0x%s, %d, %s, %s, 0x%s",
+                Integer.toHexString(device), state, deviceAddress, deviceName,
+                Integer.toHexString(codecFormat)));
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int getDeviceConnectionState(int device, String deviceAddress) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int handleDeviceConfigChange(int device, String deviceAddress,
+            String deviceName, int codecFormat) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int setPreferredDeviceForStrategy(int strategy,
+            @NonNull AudioDeviceAttributes device) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int removePreferredDeviceForStrategy(int strategy) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int setParameters(String keyValuePairs) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public boolean isMicrophoneMuted() {
+        return mIsMicMuted;
+    }
+
+    @Override
+    public int muteMicrophone(boolean on) {
+        if (mMuteMicrophoneFails) {
+            return AudioSystem.AUDIO_STATUS_ERROR;
+        }
+        mIsMicMuted = on;
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public int setCurrentImeUid(int uid) {
+        return AudioSystem.AUDIO_STATUS_OK;
+    }
+
+    @Override
+    public boolean isStreamActive(int stream, int inPastMs) {
+        return mIsStreamActive;
+    }
+}
diff --git a/services/tests/servicestests/src/com/android/server/audio/NoOpSystemServerAdapter.java b/services/tests/servicestests/src/com/android/server/audio/NoOpSystemServerAdapter.java
new file mode 100644
index 000000000000..83c566376e44
--- /dev/null
+++ b/services/tests/servicestests/src/com/android/server/audio/NoOpSystemServerAdapter.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.audio;
+
+/**
+ * Provides a no-op adapter that implements SystemServerAdapter
+ */
+public class NoOpSystemServerAdapter extends SystemServerAdapter {
+
+    NoOpSystemServerAdapter() {
+        super(null);
+    }
+
+    @Override
+    public boolean isPrivileged() {
+        return false;
+    }
+
+    @Override
+    public void sendMicrophoneMuteChangedIntent() {
+        // no-op
+    }
+
+    @Override
+    public void sendDeviceBecomingNoisyIntent() {
+        // no-op
+    }
+}