Prevent crash when rotating screen in Settings Search

Change-Id: If8134a1e96f791aacedf2e907272cee33dfc85fe
Fix: 34690393
Test: make RunSettingsRoboTests

src/com/android/settings/search2/DatabaseResultLoader.java

@@ -20,6 +20,7 @@ import android.content.Context;
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 
+import android.text.TextUtils;
 import com.android.settings.dashboard.SiteMapManager;
 import com.android.settings.overlay.FeatureFactory;
 import com.android.settings.search.IndexDatabaseHelper;
@@ -162,6 +163,9 @@ public class DatabaseResultLoader extends AsyncLoader<List<SearchResult>> {
      * @return the cleaned query string
      */
     private static String cleanQuery(String query) {
+        if (TextUtils.isEmpty(query)) {
+            return null;
+        }
         return query.trim();
     }
 

tests/robotests/src/com/android/settings/search2/SearchFragmentTest.java

@@ -17,6 +17,7 @@
 package com.android.settings.search2;
 
 import android.content.Context;
+import android.content.Loader;
 import android.os.Bundle;
 
 import com.android.internal.logging.nano.MetricsProto;
@@ -35,6 +36,9 @@ import org.robolectric.Robolectric;
 import org.robolectric.annotation.Config;
 import org.robolectric.util.ActivityController;
 
+import java.util.List;
+
+import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Matchers.eq;
@@ -96,6 +100,28 @@ public class SearchFragmentTest {
                 .getInstalledAppSearchLoader(any(Context.class), anyString());
     }
 
+    @Test
+    public void screenRotateEmptyString_ShouldNotCrash() {
+        final Bundle bundle = new Bundle();
+        ActivityController<SearchActivity> activityController =
+                Robolectric.buildActivity(SearchActivity.class);
+        activityController.setup();
+        SearchFragment fragment = (SearchFragment) activityController.get().getFragmentManager()
+                .findFragmentById(R.id.main_content);
+
+        fragment.mQuery = "";
+
+        activityController.saveInstanceState(bundle).pause().stop().destroy();
+
+        activityController = Robolectric.buildActivity(SearchActivity.class);
+        activityController.setup(bundle);
+
+        verify(mFeatureFactory.searchFeatureProvider)
+                .getDatabaseSearchLoader(any(Context.class), anyString());
+        verify(mFeatureFactory.searchFeatureProvider)
+                .getInstalledAppSearchLoader(any(Context.class), anyString());
+    }
+
     @Test
     public void queryTextChange_shouldTriggerLoader() {
         final String testQuery = "test";