Refactor CaptionAppearanceFragment to improve maintainability (2/n)

Root cause: There is a bunch of different logic of preferences in CaptionAppearanceFragment. It’s hard to implement new features and hard to maintain and hard to be testable.
Solution: Move out font size and type face preference logic of CaptionAppearanceFragment into controllers to reduce the complexity of the relationship between preference and fragment.

Bug: 197695932
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.accessibility
Change-Id: Ia52cd272495d49a772c981f51e190ff7d29ee14f

res/xml/captioning_appearance.xml

@@ -33,7 +33,8 @@
         android:entryValues="@array/captioning_font_size_selector_values"
         android:key="captioning_font_size"
         android:summary="%s"
-        android:title="@string/captioning_text_size"/>
+        android:title="@string/captioning_text_size"
+        settings:controller="com.android.settings.accessibility.CaptionFontSizeController"/>
 
     <com.android.settings.accessibility.PresetPreference
         android:key="captioning_preset"
@@ -48,7 +49,8 @@
             android:entryValues="@array/captioning_typeface_selector_values"
             android:key="captioning_typeface"
             android:summary="%s"
-            android:title="@string/captioning_typeface"/>
+            android:title="@string/captioning_typeface"
+            settings:controller="com.android.settings.accessibility.CaptionTypefaceController"/>
 
         <com.android.settings.accessibility.ColorPreference
             android:key="captioning_foreground_color"

src/com/android/settings/accessibility/CaptionAppearanceFragment.java

@@ -16,8 +16,6 @@
 
 package com.android.settings.accessibility;
 
-import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
-
 import android.app.settings.SettingsEnums;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -27,9 +25,6 @@ import android.os.Bundle;
 import android.provider.Settings;
 import android.view.accessibility.CaptioningManager;
 
-import androidx.preference.ListPreference;
-import androidx.preference.Preference;
-import androidx.preference.Preference.OnPreferenceChangeListener;
 import androidx.preference.PreferenceCategory;
 
 import com.android.settings.R;
@@ -38,13 +33,10 @@ import com.android.settings.dashboard.DashboardFragment;
 import com.android.settings.search.BaseSearchIndexProvider;
 import com.android.settingslib.search.SearchIndexable;
 
-import java.util.ArrayList;
-import java.util.List;
-
 /** Settings fragment containing font style of captioning properties. */
 @SearchIndexable(forTarget = SearchIndexable.ALL & ~SearchIndexable.ARC)
 public class CaptionAppearanceFragment extends DashboardFragment
-        implements OnPreferenceChangeListener, OnValueChangedListener {
+        implements OnValueChangedListener {
 
     private static final String TAG = "CaptionAppearanceFragment";
     private static final String PREF_BACKGROUND_COLOR = "captioning_background_color";
@@ -55,19 +47,16 @@ public class CaptionAppearanceFragment extends DashboardFragment
     private static final String PREF_WINDOW_OPACITY = "captioning_window_opacity";
     private static final String PREF_EDGE_COLOR = "captioning_edge_color";
     private static final String PREF_EDGE_TYPE = "captioning_edge_type";
-    private static final String PREF_FONT_SIZE = "captioning_font_size";
-    private static final String PREF_TYPEFACE = "captioning_typeface";
     private static final String PREF_PRESET = "captioning_preset";
     private static final String PREF_CUSTOM = "custom";
 
     private CaptioningManager mCaptioningManager;
+    private CaptionHelper mCaptionHelper;
 
     // Standard options.
-    private ListPreference mFontSize;
     private PresetPreference mPreset;
 
     // Custom options.
-    private ListPreference mTypeface;
     private ColorPreference mForegroundColor;
     private ColorPreference mForegroundOpacity;
     private EdgeTypePreference mEdgeType;
@@ -80,8 +69,6 @@ public class CaptionAppearanceFragment extends DashboardFragment
 
     private boolean mShowingCustom;
 
-    private final List<Preference> mPreferenceList = new ArrayList<>();
-
     @Override
     public int getMetricsCategory() {
         return SettingsEnums.ACCESSIBILITY_CAPTION_APPEARANCE;
@@ -92,6 +79,7 @@ public class CaptionAppearanceFragment extends DashboardFragment
         super.onCreatePreferences(savedInstanceState, rootKey);
 
         mCaptioningManager = (CaptioningManager) getSystemService(Context.CAPTIONING_SERVICE);
+        mCaptionHelper = new CaptionHelper(getContext());
 
         initializeAllPreferences();
         updateAllPreferences();
@@ -118,12 +106,6 @@ public class CaptionAppearanceFragment extends DashboardFragment
         mPreset.setValues(presetValues);
         mPreset.setTitles(presetTitles);
 
-        mFontSize = (ListPreference) findPreference(PREF_FONT_SIZE);
-
-        // Initialize the preference list
-        mPreferenceList.add(mFontSize);
-        mPreferenceList.add(mPreset);
-
         mCustom = (PreferenceCategory) findPreference(PREF_CUSTOM);
         mShowingCustom = true;
 
@@ -168,7 +150,6 @@ public class CaptionAppearanceFragment extends DashboardFragment
         mWindowOpacity.setValues(opacityValues);
 
         mEdgeType = (EdgeTypePreference) mCustom.findPreference(PREF_EDGE_TYPE);
-        mTypeface = (ListPreference) mCustom.findPreference(PREF_TYPEFACE);
     }
 
     private void installUpdateListeners() {
@@ -181,18 +162,12 @@ public class CaptionAppearanceFragment extends DashboardFragment
         mWindowColor.setOnValueChangedListener(this);
         mWindowOpacity.setOnValueChangedListener(this);
         mEdgeType.setOnValueChangedListener(this);
-
-        mTypeface.setOnPreferenceChangeListener(this);
-        mFontSize.setOnPreferenceChangeListener(this);
     }
 
     private void updateAllPreferences() {
         final int preset = mCaptioningManager.getRawUserStyle();
         mPreset.setValue(preset);
 
-        final float fontSize = mCaptioningManager.getFontScale();
-        mFontSize.setValue(Float.toString(fontSize));
-
         final ContentResolver cr = getContentResolver();
         final CaptioningManager.CaptionStyle attrs = CaptioningManager.CaptionStyle.getCustomStyle(
                 cr);
@@ -210,9 +185,6 @@ public class CaptionAppearanceFragment extends DashboardFragment
         final int windowColor = attrs.hasWindowColor() ? attrs.windowColor
                 : CaptioningManager.CaptionStyle.COLOR_UNSPECIFIED;
         parseColorOpacity(mWindowColor, mWindowOpacity, windowColor);
-
-        final String rawTypeface = attrs.mRawTypeface;
-        mTypeface.setValue(rawTypeface == null ? "" : rawTypeface);
     }
 
     /**
@@ -297,32 +269,7 @@ public class CaptionAppearanceFragment extends DashboardFragment
         } else if (mEdgeType == preference) {
             Settings.Secure.putInt(cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_EDGE_TYPE, value);
         }
-        enableCaptioningManager();
+        mCaptionHelper.setEnabled(true);
-    }
-
-    @Override
-    public boolean onPreferenceChange(Preference preference, Object value) {
-        final ContentResolver cr = getActivity().getContentResolver();
-        if (mTypeface == preference) {
-            Settings.Secure.putString(
-                    cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_TYPEFACE, (String) value);
-            enableCaptioningManager();
-        } else if (mFontSize == preference) {
-            Settings.Secure.putFloat(
-                    cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_FONT_SCALE,
-                    Float.parseFloat((String) value));
-            enableCaptioningManager();
-        }
-
-        return true;
-    }
-
-    private void enableCaptioningManager() {
-        if (mCaptioningManager.isEnabled()) {
-            return;
-        }
-        Settings.Secure.putInt(getContentResolver(),
-                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, ON);
     }
 
     @Override

src/com/android/settings/accessibility/CaptionFontSizeController.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2022 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.accessibility;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.provider.Settings;
+import android.view.accessibility.CaptioningManager;
+
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.core.BasePreferenceController;
+
+/** Preference controller for caption font size. */
+public class CaptionFontSizeController extends BasePreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private final CaptioningManager mCaptioningManager;
+    private final CaptionHelper mCaptionHelper;
+    private ListPreference mPreference;
+
+    public CaptionFontSizeController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+        mCaptioningManager = context.getSystemService(CaptioningManager.class);
+        mCaptionHelper = new CaptionHelper(context);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+
+        final float fontSize = mCaptioningManager.getFontScale();
+        mPreference.setValue(Float.toString(fontSize));
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final ContentResolver cr = mContext.getContentResolver();
+        Settings.Secure.putFloat(
+                cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_FONT_SCALE,
+                Float.parseFloat((String) newValue));
+        mPreference.setValue((String) newValue);
+        mCaptionHelper.setEnabled(true);
+        return false;
+    }
+}

src/com/android/settings/accessibility/CaptionHelper.java

@@ -16,7 +16,11 @@
 
 package com.android.settings.accessibility;
 
+import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
+import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
+
 import android.content.Context;
+import android.provider.Settings;
 import android.view.View;
 import android.view.accessibility.CaptioningManager;
 
@@ -45,6 +49,29 @@ public class CaptionHelper {
         mCaptioningManager = context.getSystemService(CaptioningManager.class);
     }
 
+    /**
+     * Sets the user's preferred captioning enabled state.
+     *
+     * @param enabled Whether to enable or disable captioning manager.
+     */
+    public void setEnabled(boolean enabled) {
+        if (isEnabled() == enabled) {
+            return;
+        }
+
+        Settings.Secure.putInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, enabled ? ON : OFF);
+    }
+
+    /**
+     * Gets if the captioning manager is enabled.
+     *
+     * @return True if the captioning manager is enabled, false otherwise.
+     */
+    public boolean isEnabled() {
+        return mCaptioningManager.isEnabled();
+    }
+
     /**
      * Updates font style of captioning properties for preview screen.
      *

src/com/android/settings/accessibility/CaptionTogglePreferenceController.java

@@ -16,12 +16,7 @@
 
 package com.android.settings.accessibility;
 
-import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
-import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
-
 import android.content.Context;
-import android.provider.Settings;
-import android.view.accessibility.CaptioningManager;
 import android.widget.Switch;
 
 import androidx.preference.PreferenceScreen;
@@ -35,11 +30,11 @@ import com.android.settingslib.widget.OnMainSwitchChangeListener;
 public class CaptionTogglePreferenceController extends TogglePreferenceController
         implements OnMainSwitchChangeListener {
 
-    private final CaptioningManager mCaptioningManager;
+    private final CaptionHelper mCaptionHelper;
 
     public CaptionTogglePreferenceController(Context context, String preferenceKey) {
         super(context, preferenceKey);
-        mCaptioningManager = context.getSystemService(CaptioningManager.class);
+        mCaptionHelper = new CaptionHelper(context);
     }
 
     @Override
@@ -49,13 +44,12 @@ public class CaptionTogglePreferenceController extends TogglePreferenceControlle
 
     @Override
     public boolean isChecked() {
-        return mCaptioningManager.isEnabled();
+        return mCaptionHelper.isEnabled();
     }
 
     @Override
     public boolean setChecked(boolean isChecked) {
-        Settings.Secure.putInt(mContext.getContentResolver(),
+        mCaptionHelper.setEnabled(isChecked);
-                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, isChecked ? ON : OFF);
         return true;
     }
 

src/com/android/settings/accessibility/CaptionTypefaceController.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2022 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.accessibility;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.provider.Settings;
+import android.view.accessibility.CaptioningManager.CaptionStyle;
+
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.core.BasePreferenceController;
+
+/** Preference controller for caption type face. */
+public class CaptionTypefaceController extends BasePreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private final CaptionHelper mCaptionHelper;
+    private ListPreference mPreference;
+
+    public CaptionTypefaceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+        mCaptionHelper = new CaptionHelper(context);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+
+        final ContentResolver cr = mContext.getContentResolver();
+        final CaptionStyle attrs = CaptionStyle.getCustomStyle(cr);
+        final String rawTypeface = attrs.mRawTypeface;
+        mPreference.setValue(rawTypeface == null ? "" : rawTypeface);
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final ContentResolver cr = mContext.getContentResolver();
+        Settings.Secure.putString(
+                cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_TYPEFACE, (String) newValue);
+        mPreference.setValue((String) newValue);
+        mCaptionHelper.setEnabled(true);
+        return false;
+    }
+}

tests/robotests/src/com/android/settings/accessibility/CaptionFontSizeControllerTest.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2022 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.accessibility;
+
+import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
+import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.provider.Settings;
+import android.view.accessibility.CaptioningManager;
+
+import androidx.preference.ListPreference;
+import androidx.preference.PreferenceScreen;
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowCaptioningManager;
+
+/** Tests for {@link CaptionFontSizeController}. */
+@RunWith(RobolectricTestRunner.class)
+public class CaptionFontSizeControllerTest {
+
+    @Rule
+    public final MockitoRule mMockitoRule = MockitoJUnit.rule();
+    @Mock
+    private PreferenceScreen mScreen;
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private CaptionFontSizeController mController;
+    private ListPreference mPreference;
+    private ShadowCaptioningManager mShadowCaptioningManager;
+
+    @Before
+    public void setUp() {
+        mController = new CaptionFontSizeController(mContext, "captioning_font_size");
+        mPreference = new ListPreference(mContext);
+        mPreference.setEntries(R.array.captioning_font_size_selector_titles);
+        mPreference.setEntryValues(R.array.captioning_font_size_selector_values);
+        when(mScreen.findPreference(mController.getPreferenceKey())).thenReturn(mPreference);
+        CaptioningManager captioningManager = mContext.getSystemService(CaptioningManager.class);
+        mShadowCaptioningManager = Shadow.extract(captioningManager);
+    }
+
+    @Test
+    public void getAvailabilityStatus_shouldReturnAvailable() {
+        assertThat(mController.getAvailabilityStatus())
+                .isEqualTo(BasePreferenceController.AVAILABLE);
+    }
+
+    @Test
+    public void displayPreference_byDefault_shouldReturnDefault() {
+        mController.displayPreference(mScreen);
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Medium");
+    }
+
+    @Test
+    public void displayPreference_bySmallValue_shouldReturnSmall() {
+        mShadowCaptioningManager.setFontScale(0.5f);
+
+        mController.displayPreference(mScreen);
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Small");
+    }
+
+    @Test
+    public void onPreferenceChange_shouldReturnSmall() {
+        mController.displayPreference(mScreen);
+
+        mController.onPreferenceChange(mPreference, "0.5");
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Small");
+    }
+
+    @Test
+    public void onPreferenceChange_shouldSetCaptionEnabled() {
+        mShadowCaptioningManager.setEnabled(false);
+        mController.displayPreference(mScreen);
+
+        mController.onPreferenceChange(mPreference, "0.5");
+
+        final boolean isCaptionEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, OFF) == ON;
+        assertThat(isCaptionEnabled).isTrue();
+    }
+}

tests/robotests/src/com/android/settings/accessibility/CaptionHelperTest.java

@@ -16,10 +16,16 @@
 
 package com.android.settings.accessibility;
 
+import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
+import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
+
+import static com.google.common.truth.Truth.assertThat;
+
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import android.content.Context;
+import android.provider.Settings;
 import android.view.View;
 import android.view.accessibility.CaptioningManager;
 
@@ -101,4 +107,26 @@ public class CaptionHelperTest {
 
         verify(mSubtitleView).setText(text);
     }
+
+    @Test
+    public void enableCaptioningManager_shouldSetCaptionEnabled() {
+        when(mCaptioningManager.isEnabled()).thenReturn(false);
+
+        mCaptionHelper.setEnabled(true);
+
+        final boolean isCaptionEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, OFF) == ON;
+        assertThat(isCaptionEnabled).isTrue();
+    }
+
+    @Test
+    public void disableCaptioningManager_shouldSetCaptionDisabled() {
+        when(mCaptioningManager.isEnabled()).thenReturn(true);
+
+        mCaptionHelper.setEnabled(false);
+
+        final boolean isCaptionEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, OFF) == ON;
+        assertThat(isCaptionEnabled).isFalse();
+    }
 }

tests/robotests/src/com/android/settings/accessibility/CaptionTypefaceControllerTest.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2022 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.accessibility;
+
+import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
+import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.provider.Settings;
+import android.view.accessibility.CaptioningManager;
+
+import androidx.preference.ListPreference;
+import androidx.preference.PreferenceScreen;
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowCaptioningManager;
+
+/** Tests for {@link CaptionTypefaceController}. */
+@RunWith(RobolectricTestRunner.class)
+public class CaptionTypefaceControllerTest {
+
+    @Rule
+    public final MockitoRule mMockitoRule = MockitoJUnit.rule();
+    @Mock
+    private PreferenceScreen mScreen;
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private CaptionTypefaceController mController;
+    private ListPreference mPreference;
+    private ShadowCaptioningManager mShadowCaptioningManager;
+
+    @Before
+    public void setUp() {
+        mController = new CaptionTypefaceController(mContext, "captioning_typeface");
+        mPreference = new ListPreference(mContext);
+        mPreference.setEntries(R.array.captioning_typeface_selector_titles);
+        mPreference.setEntryValues(R.array.captioning_typeface_selector_values);
+        when(mScreen.findPreference(mController.getPreferenceKey())).thenReturn(mPreference);
+        CaptioningManager captioningManager = mContext.getSystemService(CaptioningManager.class);
+        mShadowCaptioningManager = Shadow.extract(captioningManager);
+    }
+
+    @Test
+    public void getAvailabilityStatus_shouldReturnAvailable() {
+        assertThat(mController.getAvailabilityStatus())
+                .isEqualTo(BasePreferenceController.AVAILABLE);
+    }
+
+    @Test
+    public void displayPreference_byDefault_shouldReturnDefault() {
+        mController.displayPreference(mScreen);
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Default");
+    }
+
+    @Test
+    public void displayPreference_bySerif_shouldReturnSerif() {
+        Settings.Secure.putString(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_TYPEFACE, "serif");
+
+        mController.displayPreference(mScreen);
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Serif");
+    }
+
+    @Test
+    public void onPreferenceChange_bySerif_shouldReturnSerif() {
+        mController.displayPreference(mScreen);
+
+        mController.onPreferenceChange(mPreference, "serif");
+
+        assertThat(mPreference.getEntry().toString()).isEqualTo("Serif");
+    }
+
+    @Test
+    public void onPreferenceChange_shouldSetCaptionEnabled() {
+        mShadowCaptioningManager.setEnabled(false);
+        mController.displayPreference(mScreen);
+
+        mController.onPreferenceChange(mPreference, "serif");
+
+        final boolean isCaptionEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, OFF) == ON;
+        assertThat(isCaptionEnabled).isTrue();
+    }
+}