Bluetooth: Use config value for default max connected audio devices

* The first option in Bluetooth max connected audio devices preference
  should be using system default
* Added template based string array to show system default in the list
  preference and in preference summary when default is chosen
* Reset max connected audio devices property to empty string when
  development setting is disabled or when system default is chosen
* Added instrumentation test to check preference array size and whether
  default value is within range of preference array values
* Modified robolectric tests to verify the updated behaviors

Bug: 64767509
Test: Enable and disable multi-device mode in development settings
      make -j32 RunSettingsRoboTests
      atest SettingsUnitTests:BluetoothMaxConnectedAudioDevicesPreferenceControllerInstrumentationTest
Change-Id: I4915f12df0ac0e6f715e44e0df4a3707dde8d1a4

4 files changed, 182 insertions, 73 deletions

diff --git a/res/values/arrays.xml b/res/values/arrays.xml
index 0ccbbf44aa..e326dbe3ca 100644
--- a/res/values/arrays.xml
+++ b/res/values/arrays.xml
@@ -313,7 +313,8 @@
 
     <!-- Bluetooth developer settings: Titles for maximum number of connected audio devices -->
     <string-array name="bluetooth_max_connected_audio_devices">
-        <item>1 (Default)</item>
+        <item>Use System Default: <xliff:g id="default_bluetooth_max_connected_audio_devices">%1$d</xliff:g></item>
+        <item>1</item>
         <item>2</item>
         <item>3</item>
         <item>4</item>
@@ -321,7 +322,8 @@
     </string-array>
 
     <!-- Bluetooth developer settings: Values for maximum number of connected audio devices -->
-    <string-array name="bluetooth_max_connected_audio_devices_values">
+    <string-array translatable="false" name="bluetooth_max_connected_audio_devices_values">
+        <item></item>
         <item>1</item>
         <item>2</item>
         <item>3</item>
diff --git a/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceController.java b/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceController.java
index 5512685a13..79187f5247 100644
--- a/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceController.java
+++ b/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceController.java
@@ -22,9 +22,7 @@ import android.support.annotation.VisibleForTesting;
 import android.support.v7.preference.ListPreference;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceScreen;
-import android.text.TextUtils;
 
-import com.android.settings.R;
 import com.android.settings.core.PreferenceControllerMixin;
 import com.android.settingslib.development.DeveloperOptionsPreferenceController;
 
@@ -32,58 +30,65 @@ public class BluetoothMaxConnectedAudioDevicesPreferenceController extends
         DeveloperOptionsPreferenceController implements Preference.OnPreferenceChangeListener,
         PreferenceControllerMixin {
 
-    private static final String BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_KEY =
+    private static final String MAX_CONNECTED_AUDIO_DEVICES_PREFERENCE_KEY =
             "bluetooth_max_connected_audio_devices";
 
     @VisibleForTesting
-    static final String BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY =
+    static final String MAX_CONNECTED_AUDIO_DEVICES_PROPERTY =
             "persist.bluetooth.maxconnectedaudiodevices";
 
-    private final String[] mListValues;
-    private final String[] mListSummaries;
+    private final int mDefaultMaxConnectedAudioDevices;
     private ListPreference mPreference;
 
     public BluetoothMaxConnectedAudioDevicesPreferenceController(Context context) {
         super(context);
-
-        mListValues = context.getResources()
-                .getStringArray(R.array.bluetooth_max_connected_audio_devices_values);
-        mListSummaries = context.getResources()
-                .getStringArray(R.array.bluetooth_max_connected_audio_devices);
+        mDefaultMaxConnectedAudioDevices = mContext.getResources().getInteger(
+                com.android.internal.R.integer.config_bluetooth_max_connected_audio_devices);
     }
 
     @Override
     public String getPreferenceKey() {
-        return BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_KEY;
+        return MAX_CONNECTED_AUDIO_DEVICES_PREFERENCE_KEY;
     }
 
     @Override
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);
-
         mPreference = (ListPreference) screen.findPreference(getPreferenceKey());
+        final CharSequence[] entries = mPreference.getEntries();
+        entries[0] = String.format(entries[0].toString(), mDefaultMaxConnectedAudioDevices);
+        mPreference.setEntries(entries);
     }
 
     @Override
     public boolean onPreferenceChange(Preference preference, Object newValue) {
-        SystemProperties.set(BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, newValue.toString());
+        String newValueString = newValue.toString();
+        final ListPreference listPreference = (ListPreference) preference;
+        if (listPreference.findIndexOfValue(newValueString) <= 0) {
+            // Reset property value when default is chosen or when value is illegal
+            newValueString = "";
+        }
+        SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, newValueString);
         updateState(preference);
         return true;
     }
 
     @Override
     public void updateState(Preference preference) {
-        final String currentValue = SystemProperties.get(
-                BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY);
-        int index = 0; // Defaults to 1 device
-        for (int i = 0; i < mListValues.length; i++) {
-            if (TextUtils.equals(currentValue, mListValues[i])) {
-                index = i;
-                break;
+        final ListPreference listPreference = (ListPreference) preference;
+        final CharSequence[] entries = listPreference.getEntries();
+        final String currentValue = SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY);
+        int index = 0;
+        if (!currentValue.isEmpty()) {
+            index = listPreference.findIndexOfValue(currentValue);
+            if (index < 0) {
+                // Reset property value when value is illegal
+                SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, "");
+                index = 0;
             }
         }
-        mPreference.setValue(mListValues[index]);
-        mPreference.setSummary(mListSummaries[index]);
+        listPreference.setValueIndex(index);
+        listPreference.setSummary(entries[index]);
     }
 
     @Override
@@ -95,9 +100,8 @@ public class BluetoothMaxConnectedAudioDevicesPreferenceController extends
     @Override
     protected void onDeveloperOptionsSwitchDisabled() {
         mPreference.setEnabled(false);
-        SystemProperties.set(BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, mListValues[0]);
-        mPreference.setValue(mListValues[0]);
-        mPreference.setSummary(mListSummaries[0]);
+        SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, "");
+        updateState(mPreference);
     }
 }
 
diff --git a/tests/robotests/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerTest.java b/tests/robotests/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerTest.java
index cf892f8c25..cd56b78800 100644
--- a/tests/robotests/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerTest.java
+++ b/tests/robotests/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerTest.java
@@ -17,13 +17,15 @@
 package com.android.settings.development;
 
 import static com.android.settings.development.BluetoothMaxConnectedAudioDevicesPreferenceController
-        .BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY;
+        .MAX_CONNECTED_AUDIO_DEVICES_PROPERTY;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.when;
 
 import android.content.Context;
+import android.content.res.Resources;
 import android.os.SystemProperties;
 import android.support.v7.preference.ListPreference;
 import android.support.v7.preference.PreferenceScreen;
@@ -39,6 +41,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
 import org.robolectric.RuntimeEnvironment;
 import org.robolectric.annotation.Config;
 
@@ -47,37 +50,41 @@ import org.robolectric.annotation.Config;
         sdk = TestConfig.SDK_VERSION,
         shadows = {SettingsShadowSystemProperties.class})
 public class BluetoothMaxConnectedAudioDevicesPreferenceControllerTest {
+    private static final int TEST_MAX_CONNECTED_AUDIO_DEVICES = 3;
 
     @Mock
     private PreferenceScreen mPreferenceScreen;
+    @Spy
+    private Context mSpyContext = RuntimeEnvironment.application;
+    @Spy
+    private Resources mSpyResources = RuntimeEnvironment.application.getResources();
 
-    private Context mContext;
     private ListPreference mPreference;
     private BluetoothMaxConnectedAudioDevicesPreferenceController mController;
 
-    /**
-     * 0: 1 device maximum (Default)
-     * 1: 2 devices maximum
-     * 2: 3 devices maximum
-     * 3: 4 devices maximum
-     * 4: 5 devices maximum
-     */
-    private String[] mListValues;
-    private String[] mListSummaries;
+    private CharSequence[] mListValues;
+    private CharSequence[] mListEntries;
 
     @Before
     public void setup() {
         MockitoAnnotations.initMocks(this);
-        mContext = RuntimeEnvironment.application;
-        mPreference = new ListPreference(mContext);
-        mListValues = mContext.getResources().getStringArray(
-                R.array.bluetooth_max_connected_audio_devices_values);
-        mListSummaries = mContext.getResources().getStringArray(
-                R.array.bluetooth_max_connected_audio_devices);
-        mController = new BluetoothMaxConnectedAudioDevicesPreferenceController(mContext);
+        doReturn(mSpyResources).when(mSpyContext).getResources();
+        // Get XML values without mock
+        // Setup test list preference using XML values
+        mPreference = new ListPreference(mSpyContext);
+        mPreference.setEntries(R.array.bluetooth_max_connected_audio_devices);
+        mPreference.setEntryValues(R.array.bluetooth_max_connected_audio_devices_values);
+        // Stub default max connected audio devices to a test controlled value
+        doReturn(TEST_MAX_CONNECTED_AUDIO_DEVICES).when(mSpyResources).getInteger(
+                com.android.internal.R.integer.config_bluetooth_max_connected_audio_devices);
+        // Init the actual controller
+        mController = new BluetoothMaxConnectedAudioDevicesPreferenceController(mSpyContext);
+        // Construct preference in the controller via a mocked preference screen object
         when(mPreferenceScreen.findPreference(mController.getPreferenceKey())).thenReturn(
                 mPreference);
         mController.displayPreference(mPreferenceScreen);
+        mListValues = mPreference.getEntryValues();
+        mListEntries = mPreference.getEntries();
     }
 
     @After
@@ -86,39 +93,67 @@ public class BluetoothMaxConnectedAudioDevicesPreferenceControllerTest {
     }
 
     @Test
-    public void onPreferenceChange_setNumberOfDevices() {
-        for (int numberOfDevices = 0; numberOfDevices < mListValues.length; numberOfDevices++) {
-            mController.onPreferenceChange(mPreference, mListValues[numberOfDevices]);
-
-            final String currentValue = SystemProperties.get(
-                    BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY);
+    public void verifyResourceSizeAndRange() {
+        // Verify normal list entries and default preference entries have the same size
+        assertThat(mListEntries.length).isEqualTo(mListValues.length);
+        // Verify that list entries are formatted correctly
+        final String defaultEntry = String.format(mListEntries[0].toString(),
+                TEST_MAX_CONNECTED_AUDIO_DEVICES);
+        assertThat(mListEntries[0]).isEqualTo(defaultEntry);
+        // Update the preference
+        mController.updateState(mPreference);
+        // Verify default preference value, entry and summary
+        assertThat(mPreference.getValue()).isEqualTo(mListValues[0]);
+        assertThat(mPreference.getEntry()).isEqualTo(mListEntries[0]);
+        assertThat(mPreference.getSummary()).isEqualTo(mListEntries[0]);
+        // Verify that default system property is empty
+        assertThat(SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY)).isEmpty();
+        // Verify default property integer value
+        assertThat(SystemProperties.getInt(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY,
+                TEST_MAX_CONNECTED_AUDIO_DEVICES)).isEqualTo(TEST_MAX_CONNECTED_AUDIO_DEVICES);
+    }
 
-            assertThat(currentValue).isEqualTo(mListValues[numberOfDevices]);
-            assertThat(mPreference.getValue()).isEqualTo(mListValues[numberOfDevices]);
-            assertThat(mPreference.getSummary()).isEqualTo(mListSummaries[numberOfDevices]);
+    @Test
+    public void onPreferenceChange_setNumberOfDevices() {
+        for (final CharSequence newValue : mListValues) {
+            // Change preference using a list value
+            mController.onPreferenceChange(mPreference, newValue);
+            // Verify that value is set on the preference
+            assertThat(mPreference.getValue()).isEqualTo(newValue);
+            int index = mPreference.findIndexOfValue(newValue.toString());
+            assertThat(mPreference.getEntry()).isEqualTo(mListEntries[index]);
+            // Verify that system property is set correctly after the change
+            final String currentValue = SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY);
+            assertThat(currentValue).isEqualTo(mListValues[index]);
         }
     }
 
     @Test
     public void updateState_NumberOfDevicesUpdated_shouldSetPreference() {
-        for (int numberOfDevices = 0; numberOfDevices < mListValues.length; numberOfDevices++) {
-            SystemProperties.set(BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY,
-                    mListValues[numberOfDevices]);
-
+        for (int i = 0; i < mListValues.length; ++i) {
+            final String propertyValue = mListValues[i].toString();
+            SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, propertyValue);
+            // Verify that value is set on the preference
             mController.updateState(mPreference);
-
-            assertThat(mPreference.getValue()).isEqualTo(mListValues[numberOfDevices]);
-            assertThat(mPreference.getSummary()).isEqualTo(mListSummaries[numberOfDevices]);
+            assertThat(mPreference.getValue()).isEqualTo(mListValues[i]);
+            assertThat(mPreference.getEntry()).isEqualTo(mListEntries[i]);
+            assertThat(mPreference.getSummary()).isEqualTo(mListEntries[i]);
+            // Verify that property value remain unchanged
+            assertThat(SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY))
+                    .isEqualTo(propertyValue);
         }
     }
 
     @Test
     public void updateState_noValueSet_shouldSetDefaultTo1device() {
-        SystemProperties.set(BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, "garbage");
+        SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, "garbage");
         mController.updateState(mPreference);
 
+        // Verify that preference is reset back to default and property is reset to default
         assertThat(mPreference.getValue()).isEqualTo(mListValues[0]);
-        assertThat(mPreference.getSummary()).isEqualTo(mListSummaries[0]);
+        assertThat(mPreference.getEntry()).isEqualTo(mListEntries[0]);
+        assertThat(mPreference.getSummary()).isEqualTo(mListEntries[0]);
+        assertThat(SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY)).isEmpty();
     }
 
     @Test
@@ -126,26 +161,30 @@ public class BluetoothMaxConnectedAudioDevicesPreferenceControllerTest {
         mController.onDeveloperOptionsSwitchDisabled();
 
         assertThat(mPreference.isEnabled()).isFalse();
+        // Verify that preference is reset back to default and property is reset to default
         assertThat(mPreference.getValue()).isEqualTo(mListValues[0]);
-        assertThat(mPreference.getSummary()).isEqualTo(mListSummaries[0]);
-        final String currentValue = SystemProperties.get(
-                BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY);
-        assertThat(currentValue).isEqualTo(mListValues[0]);
+        assertThat(mPreference.getEntry()).isEqualTo(mListEntries[0]);
+        assertThat(mPreference.getSummary()).isEqualTo(mListEntries[0]);
+        assertThat(SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY)).isEmpty();
     }
 
     @Test
     public void onDeveloperOptionsSwitchEnabled_shouldEnablePreference() {
-        for (int numberOfDevices = 0; numberOfDevices < mListValues.length; numberOfDevices++) {
+        for (int i = 0; i < mListValues.length; ++i) {
+            final String initialValue = mListValues[i].toString();
             mController.onDeveloperOptionsSwitchDisabled();
             assertThat(mPreference.isEnabled()).isFalse();
 
-            SystemProperties.set(BLUETOOTH_MAX_CONNECTED_AUDIO_DEVICES_PROPERTY,
-                    mListValues[numberOfDevices]);
+            SystemProperties.set(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY, initialValue);
             mController.onDeveloperOptionsSwitchEnabled();
 
             assertThat(mPreference.isEnabled()).isTrue();
-            assertThat(mPreference.getValue()).isEqualTo(mListValues[numberOfDevices]);
-            assertThat(mPreference.getSummary()).isEqualTo(mListSummaries[numberOfDevices]);
+            assertThat(mPreference.getValue()).isEqualTo(mListValues[i]);
+            assertThat(mPreference.getEntry()).isEqualTo(mListEntries[i]);
+            assertThat(mPreference.getSummary()).isEqualTo(mListEntries[i]);
+            // Verify that property value remain unchanged
+            assertThat(SystemProperties.get(MAX_CONNECTED_AUDIO_DEVICES_PROPERTY))
+                    .isEqualTo(initialValue);
         }
     }
 }
diff --git a/tests/unit/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerInstrumentationTest.java b/tests/unit/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerInstrumentationTest.java
new file mode 100644
index 0000000000..ce8166787e
--- /dev/null
+++ b/tests/unit/src/com/android/settings/development/BluetoothMaxConnectedAudioDevicesPreferenceControllerInstrumentationTest.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2018 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.settings.development;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.android.settings.R;
+
+import org.hamcrest.CoreMatchers;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.Arrays;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class BluetoothMaxConnectedAudioDevicesPreferenceControllerInstrumentationTest {
+
+    private Context mTargetContext;
+    private String[] mListValues;
+    private String[] mListEntries;
+    private String mDefaultMaxConnectedAudioDevices;
+
+    @Before
+    public void setUp() throws Exception {
+        mTargetContext = InstrumentationRegistry.getTargetContext();
+        // Get XML values without mock
+        mListValues = mTargetContext.getResources()
+                .getStringArray(R.array.bluetooth_max_connected_audio_devices_values);
+        mListEntries = mTargetContext.getResources()
+                .getStringArray(R.array.bluetooth_max_connected_audio_devices);
+        mDefaultMaxConnectedAudioDevices = String.valueOf(mTargetContext.getResources()
+                .getInteger(
+                        com.android.internal.R.integer
+                                .config_bluetooth_max_connected_audio_devices));
+    }
+
+    @Test
+    public void verifyResource() {
+        // Verify normal list entries and default preference entries have the same size
+        Assert.assertEquals(mListEntries.length, mListValues.length);
+        Assert.assertThat(Arrays.asList(mListValues),
+                CoreMatchers.hasItem(mDefaultMaxConnectedAudioDevices));
+    }
+}