Address comments from aosp/1298476

This patch addresses the followings,
- Pass Looper to NetworkStatsSubscriptionsMonitor constructor
- Replace Looper with TestLooper in unit test
- Assert fail if result of condition check is not expected.

Bug: 154080205
Test: atest FrameworksNetTests:com.android.server.net.NetworkStatsServiceTest
      atest FrameworksNetTests:com.android.server.net.NetworkStatsSubscriptionsMonitorTest
Change-Id: Ibcaba2b38af80cc0ec9a4e428a3b3a1538bc4325

tests/net/java/com/android/server/net/NetworkStatsServiceTest.java

@@ -245,7 +245,7 @@ public class NetworkStatsServiceTest extends NetworkStatsBaseTest {
 
             @Override
             public NetworkStatsSubscriptionsMonitor makeSubscriptionsMonitor(
-                    @NonNull Context context, @NonNull Executor executor,
+                    @NonNull Context context, @NonNull Looper looper, @NonNull Executor executor,
                     @NonNull NetworkStatsService service) {
 
                 return mNetworkStatsSubscriptionsMonitor;

tests/net/java/com/android/server/net/NetworkStatsSubscriptionsMonitorTest.java

@@ -17,6 +17,7 @@
 package com.android.server.net;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.eq;
@@ -29,14 +30,13 @@ import static org.mockito.Mockito.when;
 
 import android.annotation.NonNull;
 import android.content.Context;
-import android.os.Looper;
+import android.os.test.TestLooper;
 import android.telephony.PhoneStateListener;
 import android.telephony.ServiceState;
 import android.telephony.SubscriptionManager;
 import android.telephony.TelephonyManager;
 
 import com.android.internal.util.CollectionUtils;
-import com.android.server.net.NetworkStatsSubscriptionsMonitor.Delegate;
 import com.android.server.net.NetworkStatsSubscriptionsMonitor.RatTypeListener;
 
 import org.junit.Before;
@@ -64,20 +64,17 @@ public final class NetworkStatsSubscriptionsMonitorTest {
     @Mock private PhoneStateListener mPhoneStateListener;
     @Mock private SubscriptionManager mSubscriptionManager;
     @Mock private TelephonyManager mTelephonyManager;
-    @Mock private Delegate mDelegate;
+    @Mock private NetworkStatsSubscriptionsMonitor.Delegate mDelegate;
     private final List<Integer> mTestSubList = new ArrayList<>();
 
     private final Executor mExecutor = Executors.newSingleThreadExecutor();
     private NetworkStatsSubscriptionsMonitor mMonitor;
+    private TestLooper mTestLooper = new TestLooper();
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
 
-        if (Looper.myLooper() == null) {
-            Looper.prepare();
-        }
-
         when(mTelephonyManager.createForSubscriptionId(anyInt())).thenReturn(mTelephonyManager);
 
         when(mContext.getSystemService(eq(Context.TELEPHONY_SUBSCRIPTION_SERVICE)))
@@ -85,7 +82,8 @@ public final class NetworkStatsSubscriptionsMonitorTest {
         when(mContext.getSystemService(eq(Context.TELEPHONY_SERVICE)))
                 .thenReturn(mTelephonyManager);
 
-        mMonitor = new NetworkStatsSubscriptionsMonitor(mContext, mExecutor, mDelegate);
+        mMonitor = new NetworkStatsSubscriptionsMonitor(mContext, mTestLooper.getLooper(),
+                mExecutor, mDelegate);
     }
 
     @Test
@@ -117,16 +115,18 @@ public final class NetworkStatsSubscriptionsMonitorTest {
         when(serviceState.getDataNetworkType()).thenReturn(type);
         final RatTypeListener match = CollectionUtils
                 .find(listeners, it -> it.getSubId() == subId);
-        if (match != null) {
-            match.onServiceStateChanged(serviceState);
+        if (match == null) {
+            fail("Could not find listener with subId: " + subId);
         }
+        match.onServiceStateChanged(serviceState);
     }
 
     private void addTestSub(int subId, String subscriberId) {
         // add SubId to TestSubList.
-        if (!mTestSubList.contains(subId)) {
-            mTestSubList.add(subId);
-        }
+        if (mTestSubList.contains(subId)) fail("The subscriber list already contains this ID");
+
+        mTestSubList.add(subId);
+
         final int[] subList = convertArrayListToIntArray(mTestSubList);
         when(mSubscriptionManager.getActiveAndHiddenSubscriptionIdList()).thenReturn(subList);
         when(mTelephonyManager.getSubscriberId(subId)).thenReturn(subscriberId);