[Testing] Remove Robolectric import and use AndroidJUnit4 instead in MobileDataEnabledListenerTest

1. Use AndroidJunit4 instead of RobolectricTestRunner
2. Use ApplicationProvider instead of RuntimeEnvironment to get context

Bug: 162048313
Test: atest -c MobileDataEnabledListenerTest
Change-Id: I81b3d6ac075666a45649c8d811832a40bdb1b41b
diff --git a/tests/unit/Android.bp b/tests/unit/Android.bp
index 583b46e..7556cbe 100644
--- a/tests/unit/Android.bp
+++ b/tests/unit/Android.bp
@@ -17,6 +17,7 @@
         "androidx.test.espresso.core",
         "androidx.test.espresso.contrib-nodeps",
         "androidx.test.espresso.intents-nodeps",
+        "androidx.test.ext.junit",
         "mockito-target-minus-junit4",
         "platform-test-annotations",
         "truth-prebuilt",
diff --git a/tests/unit/src/com/android/settings/network/MobileDataEnabledListenerTest.java b/tests/unit/src/com/android/settings/network/MobileDataEnabledListenerTest.java
new file mode 100644
index 0000000..190dc3d
--- /dev/null
+++ b/tests/unit/src/com/android/settings/network/MobileDataEnabledListenerTest.java
@@ -0,0 +1,85 @@
+/*
+ * 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.network;
+
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+import android.content.Context;
+import android.net.Uri;
+import android.provider.Settings;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@RunWith(AndroidJUnit4.class)
+public class MobileDataEnabledListenerTest {
+    private static final int SUB_ID_ONE = 111;
+    private static final int SUB_ID_TWO = 222;
+
+    @Mock
+    private MobileDataEnabledListener.Client mClient;
+
+    private Context mContext;
+    private MobileDataEnabledListener mListener;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mContext = ApplicationProvider.getApplicationContext();
+        mListener = new MobileDataEnabledListener(mContext, mClient);
+    }
+
+    @Test
+    public void onMobileDataEnabledChange_firesCorrectly() {
+        mListener.start(SUB_ID_ONE);
+        final Uri uri = Settings.Global.getUriFor(Settings.Global.MOBILE_DATA + SUB_ID_ONE);
+
+        mContext.getContentResolver().notifyChange(uri, null);
+
+        verify(mClient).onMobileDataEnabledChange();
+    }
+
+    @Test
+    public void onMobileDataEnabledChange_doesNotFireAfterStop() {
+        mListener.start(SUB_ID_ONE);
+        mListener.stop();
+        final Uri uri = Settings.Global.getUriFor(Settings.Global.MOBILE_DATA + SUB_ID_ONE);
+
+        mContext.getContentResolver().notifyChange(uri, null);
+
+        verify(mClient, never()).onMobileDataEnabledChange();
+    }
+
+    @Test
+    public void onMobileDataEnabledChange_changedToDifferentId_firesCorrectly() {
+        mListener.start(SUB_ID_ONE);
+        mListener.stop();
+        mListener.start(SUB_ID_TWO);
+        final Uri uri = Settings.Global.getUriFor(Settings.Global.MOBILE_DATA + SUB_ID_TWO);
+
+        mContext.getContentResolver().notifyChange(uri, null);
+
+        verify(mClient).onMobileDataEnabledChange();
+    }
+}