[Provider Model] Refactor AirplaneSafeNetworksSliceTest

- The AirplaneSafeNetworksSliceTest should restore Airplane Mode state
after tear down

- Create AirplaneModeRule to backup/restore Airplane Mode state
automaticlly

- Plan to reuse the AirplaneModeRule for other test case

Bug: 173413889
Test: atest -c AirplaneSafeNetworksSliceTest
Change-Id: Id142cf6302a188e6d82b44fcf29a395dc21f6013
diff --git a/tests/unit/src/com/android/settings/network/AirplaneSafeNetworksSliceTest.java b/tests/unit/src/com/android/settings/network/AirplaneSafeNetworksSliceTest.java
index ce47eb7..c479c25 100644
--- a/tests/unit/src/com/android/settings/network/AirplaneSafeNetworksSliceTest.java
+++ b/tests/unit/src/com/android/settings/network/AirplaneSafeNetworksSliceTest.java
@@ -34,7 +34,7 @@
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 
-import com.android.settings.AirplaneModeEnabler;
+import com.android.settings.testutils.AirplaneModeRule;
 
 import org.junit.Before;
 import org.junit.Rule;
@@ -52,19 +52,18 @@
 
     @Rule
     public MockitoRule mMocks = MockitoJUnit.rule();
+    @Rule
+    public AirplaneModeRule mAirplaneModeRule = new AirplaneModeRule();
     @Mock
     private WifiManager mWifiManager;
 
     private Context mContext;
-    private AirplaneModeEnabler mAirplaneModeEnabler;
     private AirplaneSafeNetworksSlice mAirplaneSafeNetworksSlice;
 
     @Before
     public void setUp() {
         mContext = spy(ApplicationProvider.getApplicationContext());
         when(mContext.getSystemService(Context.WIFI_SERVICE)).thenReturn(mWifiManager);
-        mAirplaneModeEnabler =
-                new AirplaneModeEnabler(mContext, null /* OnAirplaneModeChangedListener */);
 
         // Set-up specs for SliceMetadata.
         SliceProvider.setSpecs(SliceLiveData.SUPPORTED_SPECS);
@@ -74,14 +73,14 @@
 
     @Test
     public void getSlice_airplaneModeOff_shouldBeNull() {
-        mAirplaneModeEnabler.setAirplaneMode(false);
+        mAirplaneModeRule.setAirplaneMode(false);
 
         assertThat(mAirplaneSafeNetworksSlice.getSlice()).isNull();
     }
 
     @Test
     public void getSlice_wifiDisabled_shouldShowViewAirplaneSafeNetworks() {
-        mAirplaneModeEnabler.setAirplaneMode(true);
+        mAirplaneModeRule.setAirplaneMode(true);
         when(mWifiManager.isWifiEnabled()).thenReturn(false);
 
         final Slice slice = mAirplaneSafeNetworksSlice.getSlice();
@@ -94,7 +93,7 @@
 
     @Test
     public void getSlice_wifiEnabled_shouldShowTurnOffAirplaneMode() {
-        mAirplaneModeEnabler.setAirplaneMode(true);
+        mAirplaneModeRule.setAirplaneMode(true);
         when(mWifiManager.isWifiEnabled()).thenReturn(true);
 
         final Slice slice = mAirplaneSafeNetworksSlice.getSlice();
@@ -107,7 +106,7 @@
 
     @Test
     public void onNotifyChange_viewAirplaneSafeNetworks_shouldSetWifiEnabled() {
-        mAirplaneModeEnabler.setAirplaneMode(true);
+        mAirplaneModeRule.setAirplaneMode(true);
         when(mWifiManager.isWifiEnabled()).thenReturn(false);
         Intent intent = mAirplaneSafeNetworksSlice.getIntent();
 
@@ -118,12 +117,12 @@
 
     @Test
     public void onNotifyChange_turnOffAirplaneMode_shouldSetAirplaneModeOff() {
-        mAirplaneModeEnabler.setAirplaneMode(true);
+        mAirplaneModeRule.setAirplaneMode(true);
         when(mWifiManager.isWifiEnabled()).thenReturn(true);
         Intent intent = mAirplaneSafeNetworksSlice.getIntent();
 
         mAirplaneSafeNetworksSlice.onNotifyChange(intent);
 
-        assertThat(mAirplaneModeEnabler.isAirplaneModeOn()).isFalse();
+        assertThat(mAirplaneModeRule.isAirplaneModeOn()).isFalse();
     }
 }
diff --git a/tests/unit/src/com/android/settings/testutils/AirplaneModeRule.java b/tests/unit/src/com/android/settings/testutils/AirplaneModeRule.java
new file mode 100644
index 0000000..545f6ad
--- /dev/null
+++ b/tests/unit/src/com/android/settings/testutils/AirplaneModeRule.java
@@ -0,0 +1,76 @@
+/*
+ * 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.testutils;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.util.Log;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import org.junit.rules.ExternalResource;
+
+/** A test rule that is used to manager the Airplane Mode resource for testing. */
+public final class AirplaneModeRule extends ExternalResource {
+
+    private static final String TAG = "AirplaneModeRule";
+
+    private Context mContext;
+    private boolean mBackupValue;
+    private boolean mShouldRestore;
+
+    @Override
+    protected void before() throws Throwable {
+        mContext = ApplicationProvider.getApplicationContext();
+    }
+
+    @Override
+    protected void after() {
+        if (mShouldRestore) {
+            Log.d(TAG, "Restore Airplane Mode value:" + mBackupValue);
+            setAirplaneMode(mContext, mBackupValue);
+        }
+    }
+
+    public void setAirplaneMode(boolean enable) {
+        if (!mShouldRestore && isAirplaneModeOn() != enable) {
+            mShouldRestore = true;
+            mBackupValue = isAirplaneModeOn();
+            Log.d(TAG, "Backup Airplane Mode value:" + mBackupValue);
+        }
+        Log.d(TAG, "Set Airplane Mode enable:" + enable);
+        setAirplaneMode(mContext, enable);
+    }
+
+    public boolean isAirplaneModeOn() {
+        return Settings.Global.getInt(mContext.getContentResolver(),
+                Settings.Global.AIRPLANE_MODE_ON, 0) != 0;
+    }
+
+    private static void setAirplaneMode(Context context, boolean enable) {
+        // Change the system setting
+        Settings.Global.putInt(context.getContentResolver(), Settings.Global.AIRPLANE_MODE_ON,
+                enable ? 1 : 0);
+
+        // Post the intent
+        final Intent intent = new Intent(Intent.ACTION_AIRPLANE_MODE_CHANGED);
+        intent.putExtra("state", enable);
+        context.sendBroadcastAsUser(intent, UserHandle.ALL);
+    }
+}