Add unit tests for preferring bad wifi

This tests both the behavior of preferring bad wifi and
the notification.

Test: this
Change-Id: I5b93af756e898998f769015004c3286cd2ac5222
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index d5f06bc..76f4ffc 100755
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -29,6 +29,7 @@
 import static android.Manifest.permission.NETWORK_SETTINGS;
 import static android.Manifest.permission.NETWORK_STACK;
 import static android.Manifest.permission.PACKET_KEEPALIVE_OFFLOAD;
+import static android.Manifest.permission.READ_DEVICE_CONFIG;
 import static android.app.PendingIntent.FLAG_IMMUTABLE;
 import static android.content.Intent.ACTION_PACKAGE_ADDED;
 import static android.content.Intent.ACTION_PACKAGE_REMOVED;
@@ -5774,6 +5775,56 @@
         wifiCallback.assertNoCallback();
     }
 
+    public void doTestPreferBadWifi(final boolean preferBadWifi) throws Exception {
+        // Pretend we're on a carrier that restricts switching away from bad wifi, and
+        // depending on the parameter one that may indeed prefer bad wifi.
+        doReturn(0).when(mResources).getInteger(R.integer.config_networkAvoidBadWifi);
+        doReturn(preferBadWifi ? 1 : 0).when(mResources)
+                .getInteger(R.integer.config_activelyPreferBadWifi);
+        mPolicyTracker.reevaluate();
+
+        registerDefaultNetworkCallbacks();
+        final NetworkRequest wifiRequest = new NetworkRequest.Builder()
+                .clearCapabilities()
+                .addTransportType(TRANSPORT_WIFI)
+                .build();
+        final TestableNetworkCallback wifiCallback = new TestableNetworkCallback();
+        mCm.registerNetworkCallback(wifiRequest, wifiCallback);
+
+        // Bring up validated cell and unvalidated wifi.
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+        mDefaultNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connect(false);
+        wifiCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+
+        if (preferBadWifi) {
+            expectUnvalidationCheckWillNotify(mWiFiNetworkAgent, NotificationType.LOST_INTERNET);
+            mDefaultNetworkCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+        } else {
+            expectUnvalidationCheckWillNotNotify(mWiFiNetworkAgent);
+            mDefaultNetworkCallback.assertNoCallback();
+        }
+    }
+
+    @Test
+    public void testPreferBadWifi_doNotPrefer() throws Exception {
+        // Starting with U this mode is no longer supported and can't actually be tested
+        assumeFalse(SdkLevel.isAtLeastU());
+        runAsShell(READ_DEVICE_CONFIG, () -> {
+            doTestPreferBadWifi(false /* preferBadWifi */);
+        });
+    }
+
+    @Test
+    public void testPreferBadWifi_doPrefer() throws Exception {
+        runAsShell(READ_DEVICE_CONFIG, () -> {
+            doTestPreferBadWifi(true /* preferBadWifi */);
+        });
+    }
+
     @Test
     public void testAvoidBadWifi() throws Exception {
         final ContentResolver cr = mServiceContext.getContentResolver();
@@ -13010,6 +13061,12 @@
         if (null != mTestPackageDefaultNetworkCallback2) {
             mCm.unregisterNetworkCallback(mTestPackageDefaultNetworkCallback2);
         }
+        mSystemDefaultNetworkCallback = null;
+        mDefaultNetworkCallback = null;
+        mProfileDefaultNetworkCallback = null;
+        mTestPackageDefaultNetworkCallback = null;
+        mProfileDefaultNetworkCallbackAsAppUid2 = null;
+        mTestPackageDefaultNetworkCallback2 = null;
     }
 
     private void setupMultipleDefaultNetworksForOemNetworkPreferenceNotCurrentUidTest(