Add master toggle to enable/disable screen savers

The new control toggles the Settings.Secure.SCREENSAVER_ENABLED setting,
which controls if a screen saver is enabled. Also removed the "Never"
option from the WhenToDream picker, since this is now controlled via the
toggle.

Test: locally on device
Bug: 222360260
Change-Id: Ibcf52b5e2d1ad0c295f32c4c18bfc89082d074ce

tests/robotests/src/com/android/settings/dream/DreamMainSwitchPreferenceControllerTest.java

@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 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.settings.dream;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.preference.PreferenceScreen;
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settingslib.dream.DreamBackend;
+import com.android.settingslib.widget.MainSwitchPreference;
+import com.android.settingslib.widget.OnMainSwitchChangeListener;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowContentResolver;
+import org.robolectric.shadows.ShadowSettings;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(shadows = {ShadowSettings.ShadowSecure.class})
+public class DreamMainSwitchPreferenceControllerTest {
+
+    private Context mContext;
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private PreferenceScreen mScreen;
+    private DreamMainSwitchPreferenceController mController;
+    private MainSwitchPreference mPreference;
+    private DreamBackend mBackend;
+    @Mock
+    private OnMainSwitchChangeListener mChangeListener;
+    private ShadowContentResolver mShadowContentResolver;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mContext = ApplicationProvider.getApplicationContext();
+        mShadowContentResolver = Shadow.extract(mContext.getContentResolver());
+        mBackend = DreamBackend.getInstance(mContext);
+        mController = new DreamMainSwitchPreferenceController(mContext, "key");
+        mPreference = new MainSwitchPreference(mContext);
+        mPreference.setKey(mController.getPreferenceKey());
+        when(mScreen.findPreference(mPreference.getKey())).thenReturn(mPreference);
+        mController.displayPreference(mScreen);
+    }
+
+    @After
+    public void tearDown() {
+        ShadowSettings.ShadowSecure.reset();
+        mController.onStop();
+    }
+
+    @Test
+    public void testIsChecked_returnsFalse() {
+        mBackend.setEnabled(false);
+        assertThat(mController.isChecked()).isFalse();
+    }
+
+    @Test
+    public void testIsChecked_returnsTrue() {
+        mBackend.setEnabled(true);
+        assertThat(mController.isChecked()).isTrue();
+    }
+
+    @Test
+    public void testSetChecked_setFalse_disablesSetting() {
+        mBackend.setEnabled(true);
+        mController.setChecked(false);
+        assertThat(mBackend.isEnabled()).isFalse();
+    }
+
+    @Test
+    public void testSetChecked_setTrue_enablesSetting() {
+        mBackend.setEnabled(false);
+        mController.setChecked(true);
+        assertThat(mBackend.isEnabled()).isTrue();
+    }
+
+    @Test
+    public void testIsSliceable_returnsFalse() {
+        assertThat(mController.isSliceable()).isFalse();
+    }
+
+    @Test
+    public void testRegisterAndUnregister() {
+        mController.onStart();
+        assertThat(mShadowContentResolver.getContentObservers(
+                Settings.Secure.getUriFor(Settings.Secure.SCREENSAVER_ENABLED))).hasSize(1);
+
+        mController.onStop();
+        assertThat(mShadowContentResolver.getContentObservers(
+                Settings.Secure.getUriFor(Settings.Secure.SCREENSAVER_ENABLED))).isEmpty();
+    }
+
+    @Test
+    public void testUpdateState() {
+        mController.onStart();
+
+        mBackend.setEnabled(true);
+        triggerOnChangeListener();
+        assertThat(mPreference.isChecked()).isTrue();
+
+        mBackend.setEnabled(false);
+        triggerOnChangeListener();
+        assertThat(mPreference.isChecked()).isFalse();
+
+        mBackend.setEnabled(true);
+        triggerOnChangeListener();
+        assertThat(mPreference.isChecked()).isTrue();
+    }
+
+    private void triggerOnChangeListener() {
+        mShadowContentResolver.getContentObservers(
+                        Settings.Secure.getUriFor(Settings.Secure.SCREENSAVER_ENABLED))
+                .forEach(contentObserver -> contentObserver.onChange(false));
+    }
+}

tests/robotests/src/com/android/settings/dream/DreamPickerControllerTest.java

@@ -62,7 +62,8 @@ public class DreamPickerControllerTest {
     }
 
     private DreamPickerController buildController() {
-        final DreamPickerController controller = new DreamPickerController(mContext, mBackend);
+        final DreamPickerController controller = new DreamPickerController(mContext, "key",
+                mBackend);
         controller.displayPreference(mScreen);
         return controller;
     }