Add test for ConnectivityService API isPrivateDnsBroken

Bug: 189161363
Test: atest android.net.cts.ConnectivityManagerTest
      atest CtsNetTestCasesLatestSdk:ConnectivityManagerTest
Original-Change: https://android-review.googlesource.com/1719395
Merged-In: Ib45aa439683d48360652a91d7a0609dc82adda33
Change-Id: Ib45aa439683d48360652a91d7a0609dc82adda33
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index acec9a4..ae59dc4 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -152,6 +152,7 @@
 import com.android.networkstack.apishim.common.ConnectivityManagerShim;
 import com.android.testutils.CompatUtil;
 import com.android.testutils.DevSdkIgnoreRule;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
 import com.android.testutils.DevSdkIgnoreRuleKt;
 import com.android.testutils.RecorderCallback.CallbackEntry;
 import com.android.testutils.SkipPresubmit;
@@ -674,6 +675,31 @@
                 .build();
     }
 
+    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
+    public void testIsPrivateDnsBroken() throws InterruptedException {
+        final String invalidPrivateDnsServer = "invalidhostname.example.com";
+        final String goodPrivateDnsServer = "dns.google";
+        mCtsNetUtils.storePrivateDnsSetting();
+        final TestableNetworkCallback cb = new TestableNetworkCallback();
+        mCm.registerNetworkCallback(makeWifiNetworkRequest(), cb);
+        try {
+            // Verifying the good private DNS sever
+            mCtsNetUtils.setPrivateDnsStrictMode(goodPrivateDnsServer);
+            final Network networkForPrivateDns =  mCtsNetUtils.ensureWifiConnected();
+            cb.eventuallyExpect(CallbackEntry.NETWORK_CAPS_UPDATED, NETWORK_CALLBACK_TIMEOUT_MS,
+                    entry -> (!((CallbackEntry.CapabilitiesChanged) entry).getCaps()
+                    .isPrivateDnsBroken()) && networkForPrivateDns.equals(entry.getNetwork()));
+
+            // Verifying the broken private DNS sever
+            mCtsNetUtils.setPrivateDnsStrictMode(invalidPrivateDnsServer);
+            cb.eventuallyExpect(CallbackEntry.NETWORK_CAPS_UPDATED, NETWORK_CALLBACK_TIMEOUT_MS,
+                    entry -> (((CallbackEntry.CapabilitiesChanged) entry).getCaps()
+                    .isPrivateDnsBroken()) && networkForPrivateDns.equals(entry.getNetwork()));
+        } finally {
+            mCtsNetUtils.restorePrivateDnsSetting();
+        }
+    }
+
     /**
      * Exercises both registerNetworkCallback and unregisterNetworkCallback. This checks to
      * see if we get a callback for the TRANSPORT_WIFI transport type being available.