Fix minor bug and deflaky for DnsResolverTest

1. Add the missing countdown() in the test callback
2. Add ensureWifiConnected() to prevent no available network problem.
3. Increase the timeout for awaiting private DNS setting because
   current one might not be enough.

Bug: 168027339
Test atest

Change-Id: I0ee8161fac3b6db7a000ddb0a057cd91a17bd7d5
Merged-In: I91190d8644ff7a7dfaf4fa3f2d43c17f67dfac11
Original-Change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1486780
(cherry picked from commit e2005b0138)

tests/cts/net/src/android/net/cts/DnsResolverTest.java

@@ -28,6 +28,7 @@ import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.Context;
 import android.content.ContentResolver;
+import android.content.pm.PackageManager;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
 import android.net.DnsResolver;
@@ -91,6 +92,7 @@ public class DnsResolverTest extends AndroidTestCase {
 
     private ContentResolver mCR;
     private ConnectivityManager mCM;
+    private PackageManager mPackageManager;
     private CtsNetUtils mCtsNetUtils;
     private Executor mExecutor;
     private Executor mExecutorInline;
@@ -109,6 +111,7 @@ public class DnsResolverTest extends AndroidTestCase {
         mCR = getContext().getContentResolver();
         mCtsNetUtils = new CtsNetUtils(getContext());
         mCtsNetUtils.storePrivateDnsSetting();
+        mPackageManager = mContext.getPackageManager();
     }
 
     @Override
@@ -128,6 +131,9 @@ public class DnsResolverTest extends AndroidTestCase {
     }
 
     private Network[] getTestableNetworks() {
+        if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_WIFI)) {
+            mCtsNetUtils.ensureWifiConnected();
+        }
         final ArrayList<Network> testableNetworks = new ArrayList<Network>();
         for (Network network : mCM.getAllNetworks()) {
             final NetworkCapabilities nc = mCM.getNetworkCapabilities(network);
@@ -555,6 +561,7 @@ public class DnsResolverTest extends AndroidTestCase {
         @Override
         public void onError(@NonNull DnsResolver.DnsException error) {
             mErrorMsg = mMsg + error.getMessage();
+            mLatch.countDown();
         }
     }
 

tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java

@@ -84,7 +84,7 @@ public final class CtsNetUtils {
     private static final int SOCKET_TIMEOUT_MS = 2000;
     private static final int PRIVATE_DNS_PROBE_MS = 1_000;
 
-    private static final int PRIVATE_DNS_SETTING_TIMEOUT_MS = 6_000;
+    private static final int PRIVATE_DNS_SETTING_TIMEOUT_MS = 10_000;
     private static final int CONNECTIVITY_CHANGE_TIMEOUT_SECS = 30;
     public static final int HTTP_PORT = 80;
     public static final String TEST_HOST = "connectivitycheck.gstatic.com";