Add SearchIndexable to improve search coverage

- Add searachIndex test
- Increase accessibility framework feature fragment coverage

Bug: 197695932
Test: make RunSettingsRoboTests
Change-Id: Icb7e2cf70bb0443304af7866efd48bed1d9af5bf

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

@@ -18,6 +18,7 @@ package com.android.settings.accessibility;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import android.app.settings.SettingsEnums;
 import android.content.Context;
 
 import androidx.test.core.app.ApplicationProvider;
@@ -25,6 +26,7 @@ import androidx.test.core.app.ApplicationProvider;
 import com.android.settings.R;
 import com.android.settings.testutils.XmlTestUtils;
 
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
@@ -35,7 +37,30 @@ import java.util.List;
 @RunWith(RobolectricTestRunner.class)
 public class AudioAdjustmentFragmentTest {
 
-    private Context mContext = ApplicationProvider.getApplicationContext();
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private AudioAdjustmentFragment mFragment;
+
+    @Before
+    public void setUp() {
+        mFragment = new AudioAdjustmentFragment();
+    }
+
+    @Test
+    public void getMetricsCategory_returnsCorrectCategory() {
+        assertThat(mFragment.getMetricsCategory()).isEqualTo(
+                SettingsEnums.ACCESSIBILITY_AUDIO_ADJUSTMENT);
+    }
+
+    @Test
+    public void getPreferenceScreenResId_returnsCorrectXml() {
+        assertThat(mFragment.getPreferenceScreenResId()).isEqualTo(
+                R.xml.accessibility_audio_adjustment);
+    }
+
+    @Test
+    public void getLogTag_returnsCorrectTag() {
+        assertThat(mFragment.getLogTag()).isEqualTo("AudioAdjustmentFragment");
+    }
 
     @Test
     public void getNonIndexableKeys_existInXmlLayout() {