Add camera extension fallback toggle

Android camera extensions
(https://source.android.com/docs/core/camera/camerax-vendor-extensions)
will be able to use SW fallback implementations
on devices that do not ship the corresponding
the device specific functionality.
Since the SW fallback will be using a new data
path, it was suggested that users must be able to
control and enable/disable the SW fallback
via the Settings app.

Bug: 297083874
Test: atest packages/apps/Settings/tests/unit/src/com/android/settings/privacy/CameraExtensionsFallbackPreferenceControllerTest.java

Change-Id: I1b97777babe1c9f4ea4f2f6ee3d8251fea11146e

tests/unit/src/com/android/settings/privacy/CameraExtensionsFallbackPreferenceControllerTest.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2023 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.privacy;
+
+import static com.android.settings.core.BasePreferenceController.AVAILABLE;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.android.settings.privacy.CameraExtensionsFallbackPreferenceController;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class CameraExtensionsFallbackPreferenceControllerTest {
+
+    private static final String KEY = "camera_extensions_fallback";
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+
+    private int mOriginalPreference;
+    private ContentResolver mContentResolver;
+    private CameraExtensionsFallbackPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        mContentResolver = mContext.getContentResolver();
+        mOriginalPreference = Settings.Secure.getInt(mContentResolver,
+                Settings.Secure.CAMERA_EXTENSIONS_FALLBACK, 1);
+        mController = new CameraExtensionsFallbackPreferenceController(mContext, KEY);
+    }
+
+    @After
+    public void tearDown() {
+        Settings.Secure.putInt(mContentResolver, Settings.Secure.CAMERA_EXTENSIONS_FALLBACK,
+                mOriginalPreference);
+    }
+
+    @Test
+    public void getAvailability_returnAvailable() {
+        assertThat(mController.getAvailabilityStatus()).isEqualTo(AVAILABLE);
+    }
+
+    @Test
+    public void setChecked_disable_shouldTurnOff() {
+        Settings.Secure.putInt(mContentResolver,
+                Settings.Secure.CAMERA_EXTENSIONS_FALLBACK, 1);
+
+        assertThat(mController.isChecked()).isTrue();
+
+        mController.setChecked(false);
+
+        assertThat(Settings.Secure.getInt(mContentResolver,
+                Settings.Secure.CAMERA_EXTENSIONS_FALLBACK, -1)).isEqualTo(0);
+    }
+
+    @Test
+    public void setChecked_enable_shouldTurnOn() {
+        Settings.Secure.putInt(mContentResolver,
+                Settings.Secure.CAMERA_EXTENSIONS_FALLBACK, 0);
+
+        assertThat(mController.isChecked()).isFalse();
+
+        mController.setChecked(true);
+
+        assertThat(Settings.Secure.getInt(mContentResolver,
+                Settings.Secure.CAMERA_EXTENSIONS_FALLBACK, -1)).isEqualTo(1);
+    }
+}