Add CTS for registerBestMatchingNetworkCallback

Bug: 188657173
Test: atest CtsNetTestCases:android.net.cts.NetworkAgentTest \
      CtsNetTestCases:android.net.cts.ConnectivityManagerTest
Test: atest CtsNetTestCasesLatestSdk:android.net.cts.NetworkAgentTest \
      CtsNetTestCasesLatestSdk:android.net.cts.ConnectivityManagerTest
      on R device
Merged-In: I81abc1742a3aa965b444d0196f4eaa2393dcad1c
Change-Id: I81abc1742a3aa965b444d0196f4eaa2393dcad1c
  (cherry-picked from aosp/1727824)

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

@@ -650,6 +650,18 @@ public class ConnectivityManagerTest {
         mCm.getBackgroundDataSetting();
     }
 
+    private NetworkRequest makeDefaultRequest() {
+        // Make a request that is similar to the way framework tracks the system
+        // default network.
+        return new NetworkRequest.Builder()
+                .clearCapabilities()
+                .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED)
+                .addCapability(NetworkCapabilities.NET_CAPABILITY_TRUSTED)
+                .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_VPN)
+                .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
+                .build();
+    }
+
     private NetworkRequest makeWifiNetworkRequest() {
         return new NetworkRequest.Builder()
                 .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
@@ -688,12 +700,14 @@ public class ConnectivityManagerTest {
 
         final TestNetworkCallback systemDefaultCallback = new TestNetworkCallback();
         final TestNetworkCallback perUidCallback = new TestNetworkCallback();
+        final TestNetworkCallback bestMatchingCallback = new TestNetworkCallback();
         final Handler h = new Handler(Looper.getMainLooper());
         if (TestUtils.shouldTestSApis()) {
             runWithShellPermissionIdentity(() -> {
                 mCmShim.registerSystemDefaultNetworkCallback(systemDefaultCallback, h);
                 mCmShim.registerDefaultNetworkCallbackForUid(Process.myUid(), perUidCallback, h);
             }, NETWORK_SETTINGS);
+            mCm.registerBestMatchingNetworkCallback(makeDefaultRequest(), bestMatchingCallback, h);
         }
 
         Network wifiNetwork = null;
@@ -719,6 +733,10 @@ public class ConnectivityManagerTest {
                 assertNotNull("Did not receive onAvailable on per-UID default network callback",
                         perUidNetwork);
                 assertEquals(defaultNetwork, perUidNetwork);
+                final Network bestMatchingNetwork = bestMatchingCallback.waitForAvailable();
+                assertNotNull("Did not receive onAvailable on best matching network callback",
+                        bestMatchingNetwork);
+                assertEquals(defaultNetwork, bestMatchingNetwork);
             }
 
         } catch (InterruptedException e) {
@@ -729,6 +747,7 @@ public class ConnectivityManagerTest {
             if (TestUtils.shouldTestSApis()) {
                 mCm.unregisterNetworkCallback(systemDefaultCallback);
                 mCm.unregisterNetworkCallback(perUidCallback);
+                mCm.unregisterNetworkCallback(bestMatchingCallback);
             }
         }
     }

tests/cts/net/src/android/net/cts/NetworkAgentTest.kt

@@ -66,6 +66,7 @@ import android.net.cts.NetworkAgentTest.TestableNetworkAgent.CallbackEntry.OnSta
 import android.net.cts.NetworkAgentTest.TestableNetworkAgent.CallbackEntry.OnStopSocketKeepalive
 import android.net.cts.NetworkAgentTest.TestableNetworkAgent.CallbackEntry.OnValidationStatus
 import android.os.Build
+import android.os.Handler
 import android.os.HandlerThread
 import android.os.Looper
 import android.os.Message
@@ -331,6 +332,15 @@ class NetworkAgentTest {
         callbacksToCleanUp.add(callback)
     }
 
+    private fun registerBestMatchingNetworkCallback(
+        request: NetworkRequest,
+        callback: TestableNetworkCallback,
+        handler: Handler
+    ) {
+        mCM!!.registerBestMatchingNetworkCallback(request, callback, handler)
+        callbacksToCleanUp.add(callback)
+    }
+
     private fun makeTestNetworkRequest(specifier: String? = null): NetworkRequest {
         return NetworkRequest.Builder()
                 .clearCapabilities()
@@ -868,4 +878,60 @@ class NetworkAgentTest {
         val testNetworkSnapshot = snapshots.findLast { it.network == agent.network }
         assertEquals(imsi, testNetworkSnapshot!!.subscriberId)
     }
+
+    @Test
+    @IgnoreUpTo(Build.VERSION_CODES.R)
+    // TODO: Refactor helper functions to util class and move this test case to
+    //  {@link android.net.cts.ConnectivityManagerTest}.
+    fun testRegisterBestMatchingNetworkCallback() {
+        // Register best matching network callback with additional condition that will be
+        // exercised later. This assumes the test network agent has NOT_VCN_MANAGED in it and
+        // does not have NET_CAPABILITY_TEMPORARILY_NOT_METERED.
+        val bestMatchingCb = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
+        registerBestMatchingNetworkCallback(NetworkRequest.Builder()
+                .clearCapabilities()
+                .addTransportType(TRANSPORT_TEST)
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+                .build(), bestMatchingCb, mHandlerThread.threadHandler)
+
+        val (agent1, _) = createConnectedNetworkAgent(specifier = "AGENT-1")
+        bestMatchingCb.expectAvailableThenValidatedCallbacks(agent1.network!!)
+        // Make agent1 worse so when agent2 shows up, the callback will see that.
+        agent1.sendNetworkScore(NetworkScore.Builder().setExiting(true).build())
+        bestMatchingCb.assertNoCallback(NO_CALLBACK_TIMEOUT)
+
+        val (agent2, _) = createConnectedNetworkAgent(specifier = "AGENT-2")
+        bestMatchingCb.expectAvailableDoubleValidatedCallbacks(agent2.network!!)
+
+        // Change something on agent1 to trigger capabilities changed, since the callback
+        // only cares about the best network, verify it received nothing from agent1.
+        val ncAgent1 = agent1.nc
+        ncAgent1.addCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED)
+        agent1.sendNetworkCapabilities(ncAgent1)
+        bestMatchingCb.assertNoCallback(NO_CALLBACK_TIMEOUT)
+
+        // Make agent1 the best network again, verify the callback now tracks agent1.
+        agent1.sendNetworkScore(NetworkScore.Builder()
+                .setExiting(false).setTransportPrimary(true).build())
+        bestMatchingCb.expectAvailableCallbacks(agent1.network!!)
+
+        // Make agent1 temporary vcn managed, which will not satisfying the request.
+        // Verify the callback switch from/to the other network accordingly.
+        ncAgent1.removeCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+        agent1.sendNetworkCapabilities(ncAgent1)
+        bestMatchingCb.expectAvailableCallbacks(agent2.network!!)
+        ncAgent1.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+        agent1.sendNetworkCapabilities(ncAgent1)
+        bestMatchingCb.expectAvailableDoubleValidatedCallbacks(agent1.network!!)
+
+        // Verify the callback doesn't care about agent2 disconnect.
+        agent2.unregister()
+        agentsToCleanUp.remove(agent2)
+        bestMatchingCb.assertNoCallback()
+        agent1.unregister()
+        agentsToCleanUp.remove(agent1)
+        bestMatchingCb.expectCallback<Lost>(agent1.network!!)
+
+        // tearDown() will unregister the requests and agents
+    }
 }