Add unit tests related to data accounting for VPNs with one underlying

network.

This is to establish a baseline for the existing behavior, and to ensure
that following changes are not causing a regression in existing
behavior.

This CL is also adding missing cleanup for NetworkStatsCollectionTest
which was forcing all network types in NetworkTemplate that was causing
NetworkStatsService related tests to fail.

Bug: 113122541
Bug: 120145746
Test: atest FrameworksNetTests
Change-Id: I285f186cfb16bc9fa704c797996b1e4f8a73dee4

core/java/android/net/NetworkTemplate.java

@@ -40,6 +40,7 @@ import android.os.Parcelable;
 import android.util.BackupUtils;
 import android.util.Log;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ArrayUtils;
 
 import java.io.ByteArrayOutputStream;
@@ -89,10 +90,22 @@ public class NetworkTemplate implements Parcelable {
 
     private static boolean sForceAllNetworkTypes = false;
 
+    /**
+     * Results in matching against all mobile network types.
+     *
+     * <p>See {@link #matchesMobile} and {@link matchesMobileWildcard}.
+     */
+    @VisibleForTesting
     public static void forceAllNetworkTypes() {
         sForceAllNetworkTypes = true;
     }
 
+    /** Resets the affect of {@link #forceAllNetworkTypes}. */
+    @VisibleForTesting
+    public static void resetForceAllNetworkTypes() {
+        sForceAllNetworkTypes = false;
+    }
+
     /**
      * Template to match {@link ConnectivityManager#TYPE_MOBILE} networks with
      * the given IMSI.