Merge changes I627dcd0f,I81abc174,Id7948d21

* changes:
  Fix expectCallback does not fail when no callback received
  Add CTS for registerBestMatchingNetworkCallback
  No-op refactoring of NetworkAgentTest

tests/common/java/android/net/NetworkProviderTest.kt

@@ -18,6 +18,7 @@ package android.net
 
 import android.app.Instrumentation
 import android.content.Context
+import android.net.NetworkCapabilities.NET_CAPABILITY_TRUSTED
 import android.net.NetworkCapabilities.TRANSPORT_TEST
 import android.net.NetworkProviderTest.TestNetworkCallback.CallbackEntry.OnUnavailable
 import android.net.NetworkProviderTest.TestNetworkProvider.CallbackEntry.OnNetworkRequestWithdrawn
@@ -25,14 +26,18 @@ import android.net.NetworkProviderTest.TestNetworkProvider.CallbackEntry.OnNetwo
 import android.os.Build
 import android.os.HandlerThread
 import android.os.Looper
+import android.util.Log
 import androidx.test.InstrumentationRegistry
 import com.android.net.module.util.ArrayTrackRecord
 import com.android.testutils.CompatUtil
+import com.android.testutils.DevSdkIgnoreRule
+import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
 import com.android.testutils.DevSdkIgnoreRunner
 import com.android.testutils.isDevSdkInRange
 import org.junit.After
 import org.junit.Before
+import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.mockito.Mockito.doReturn
@@ -41,6 +46,7 @@ import org.mockito.Mockito.verifyNoMoreInteractions
 import java.util.UUID
 import kotlin.test.assertEquals
 import kotlin.test.assertNotEquals
+import kotlin.test.fail
 
 private const val DEFAULT_TIMEOUT_MS = 5000L
 private val instrumentation: Instrumentation
@@ -51,6 +57,8 @@ private val PROVIDER_NAME = "NetworkProviderTest"
 @RunWith(DevSdkIgnoreRunner::class)
 @IgnoreUpTo(Build.VERSION_CODES.Q)
 class NetworkProviderTest {
+    @Rule @JvmField
+    val mIgnoreRule = DevSdkIgnoreRule()
     private val mCm = context.getSystemService(ConnectivityManager::class.java)
     private val mHandlerThread = HandlerThread("${javaClass.simpleName} handler thread")
 
@@ -68,6 +76,7 @@ class NetworkProviderTest {
 
     private class TestNetworkProvider(context: Context, looper: Looper) :
             NetworkProvider(context, looper, PROVIDER_NAME) {
+        private val TAG = this::class.simpleName
         private val seenEvents = ArrayTrackRecord<CallbackEntry>().newReadHead()
 
         sealed class CallbackEntry {
@@ -80,22 +89,30 @@ class NetworkProviderTest {
         }
 
         override fun onNetworkRequested(request: NetworkRequest, score: Int, id: Int) {
+            Log.d(TAG, "onNetworkRequested $request, $score, $id")
             seenEvents.add(OnNetworkRequested(request, score, id))
         }
 
         override fun onNetworkRequestWithdrawn(request: NetworkRequest) {
+            Log.d(TAG, "onNetworkRequestWithdrawn $request")
             seenEvents.add(OnNetworkRequestWithdrawn(request))
         }
 
-        inline fun <reified T : CallbackEntry> expectCallback(
+        inline fun <reified T : CallbackEntry> eventuallyExpectCallbackThat(
             crossinline predicate: (T) -> Boolean
         ) = seenEvents.poll(DEFAULT_TIMEOUT_MS) { it is T && predicate(it) }
+                ?: fail("Did not receive callback after ${DEFAULT_TIMEOUT_MS}ms")
     }
 
     private fun createNetworkProvider(ctx: Context = context): TestNetworkProvider {
         return TestNetworkProvider(ctx, mHandlerThread.looper)
     }
 
+    // In S+ framework, do not run this test, since the provider will no longer receive
+    // onNetworkRequested for every request. Instead, provider needs to
+    // call {@code registerNetworkOffer} with the description of networks they
+    // might have ability to setup, and expects {@link NetworkOfferCallback#onNetworkNeeded}.
+    @IgnoreAfter(Build.VERSION_CODES.R)
     @Test
     fun testOnNetworkRequested() {
         val provider = createNetworkProvider()
@@ -105,13 +122,15 @@ class NetworkProviderTest {
 
         val specifier = CompatUtil.makeTestNetworkSpecifier(
                 UUID.randomUUID().toString())
+        // Test network is not allowed to be trusted.
         val nr: NetworkRequest = NetworkRequest.Builder()
                 .addTransportType(TRANSPORT_TEST)
+                .removeCapability(NET_CAPABILITY_TRUSTED)
                 .setNetworkSpecifier(specifier)
                 .build()
         val cb = ConnectivityManager.NetworkCallback()
         mCm.requestNetwork(nr, cb)
-        provider.expectCallback<OnNetworkRequested>() { callback ->
+        provider.eventuallyExpectCallbackThat<OnNetworkRequested>() { callback ->
             callback.request.getNetworkSpecifier() == specifier &&
             callback.request.hasTransport(TRANSPORT_TEST)
         }
@@ -131,22 +150,24 @@ class NetworkProviderTest {
         val config = NetworkAgentConfig.Builder().build()
         val agent = object : NetworkAgent(context, mHandlerThread.looper, "TestAgent", nc, lp,
                 initialScore, config, provider) {}
+        agent.register()
+        agent.markConnected()
 
-        provider.expectCallback<OnNetworkRequested>() { callback ->
+        provider.eventuallyExpectCallbackThat<OnNetworkRequested>() { callback ->
             callback.request.getNetworkSpecifier() == specifier &&
             callback.score == initialScore &&
             callback.id == agent.providerId
         }
 
         agent.sendNetworkScore(updatedScore)
-        provider.expectCallback<OnNetworkRequested>() { callback ->
+        provider.eventuallyExpectCallbackThat<OnNetworkRequested>() { callback ->
             callback.request.getNetworkSpecifier() == specifier &&
             callback.score == updatedScore &&
             callback.id == agent.providerId
         }
 
         mCm.unregisterNetworkCallback(cb)
-        provider.expectCallback<OnNetworkRequestWithdrawn>() { callback ->
+        provider.eventuallyExpectCallbackThat<OnNetworkRequestWithdrawn>() { callback ->
             callback.request.getNetworkSpecifier() == specifier &&
             callback.request.hasTransport(TRANSPORT_TEST)
         }

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)
@@ -710,12 +722,14 @@ 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;
@@ -741,6 +755,10 @@ 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) {
@@ -751,6 +769,7 @@ 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
@@ -269,10 +270,9 @@ class NetworkAgentTest {
             history.add(OnSignalStrengthThresholdsUpdated(thresholds))
         }
 
-        fun expectEmptySignalStrengths() {
+        fun expectSignalStrengths(thresholds: IntArray? = intArrayOf()) {
             expectCallback<OnSignalStrengthThresholdsUpdated>().let {
-                // intArrayOf() without arguments makes an empty array
+                assertArrayEquals(thresholds, it.thresholds)
-                assertArrayEquals(intArrayOf(), it.thresholds)
             }
         }
 
@@ -292,7 +292,7 @@ class NetworkAgentTest {
         // a NetworkAgent whose network does not require validation (which test networks do
         // not, since they lack the INTERNET capability). It always contains the default argument
         // for the URI.
-        fun expectNoInternetValidationStatus() = expectCallback<OnValidationStatus>().let {
+        fun expectValidationBypassedStatus() = expectCallback<OnValidationStatus>().let {
             assertEquals(it.status, VALID_NETWORK)
             // The returned Uri is parsed from the empty string, which means it's an
             // instance of the (private) Uri.StringUri. There are no real good ways
@@ -332,9 +332,30 @@ 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()
+                .addTransportType(TRANSPORT_TEST)
+                .also {
+                    if (specifier != null) {
+                        it.setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(specifier))
+                    }
+                }
+                .build()
+    }
+
     private fun createNetworkAgent(
         context: Context = realContext,
-        name: String? = null,
+        specifier: String? = null,
         initialNc: NetworkCapabilities? = null,
         initialLp: LinkProperties? = null,
         initialConfig: NetworkAgentConfig? = null
@@ -349,8 +370,8 @@ class NetworkAgentTest {
             if (SdkLevel.isAtLeastS()) {
                 addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
             }
-            if (null != name) {
+            if (null != specifier) {
-                setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(name))
+                setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(specifier))
             }
         }
         val lp = initialLp ?: LinkProperties().apply {
@@ -365,21 +386,22 @@ class NetworkAgentTest {
 
     private fun createConnectedNetworkAgent(
         context: Context = realContext,
-        name: String? = null,
+        specifier: String? = UUID.randomUUID().toString(),
-        initialConfig: NetworkAgentConfig? = null
+        initialConfig: NetworkAgentConfig? = null,
+        expectedInitSignalStrengthThresholds: IntArray? = intArrayOf()
     ): Pair<TestableNetworkAgent, TestableNetworkCallback> {
-        val request: NetworkRequest = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .build()
         val callback = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        requestNetwork(request, callback)
+        // Ensure this NetworkAgent is never unneeded by filing a request with its specifier.
-        val config = initialConfig ?: NetworkAgentConfig.Builder().build()
+        requestNetwork(makeTestNetworkRequest(specifier = specifier), callback)
-        val agent = createNetworkAgent(context, name, initialConfig = config)
+        val agent = createNetworkAgent(context, specifier, initialConfig = initialConfig)
         agent.setTeardownDelayMillis(0)
+        // Connect the agent and verify initial status callbacks.
         agent.register()
         agent.markConnected()
         agent.expectCallback<OnNetworkCreated>()
+        agent.expectSignalStrengths(expectedInitSignalStrengthThresholds)
+        agent.expectValidationBypassedStatus()
+        callback.expectAvailableThenValidatedCallbacks(agent.network!!)
         return agent to callback
     }
 
@@ -413,7 +435,6 @@ class NetworkAgentTest {
                 .setLegacySubType(subtypeLTE)
                 .setLegacySubTypeName(subtypeNameLTE).build()
         val (agent, callback) = createConnectedNetworkAgent(initialConfig = config)
-            callback.expectAvailableThenValidatedCallbacks(agent.network)
             agent.setLegacySubtype(subtypeUMTS, subtypeNameUMTS)
 
             // There is no callback when networkInfo changes,
@@ -433,12 +454,8 @@ class NetworkAgentTest {
     @Test
     fun testConnectAndUnregister() {
         val (agent, callback) = createConnectedNetworkAgent()
-        callback.expectAvailableThenValidatedCallbacks(agent.network)
-        agent.expectEmptySignalStrengths()
-        agent.expectNoInternetValidationStatus()
-
         unregister(agent)
-        callback.expectCallback<Lost>(agent.network)
+        callback.expectCallback<Lost>(agent.network!!)
         assertFailsWith<IllegalStateException>("Must not be able to register an agent twice") {
             agent.register()
         }
@@ -446,11 +463,8 @@ class NetworkAgentTest {
 
     @Test
     fun testOnBandwidthUpdateRequested() {
-        val (agent, callback) = createConnectedNetworkAgent()
+        val (agent, _) = createConnectedNetworkAgent()
-        callback.expectAvailableThenValidatedCallbacks(agent.network)
+        mCM.requestBandwidthUpdate(agent.network!!)
-        agent.expectEmptySignalStrengths()
-        agent.expectNoInternetValidationStatus()
-        mCM.requestBandwidthUpdate(agent.network)
         agent.expectCallback<OnBandwidthUpdateRequested>()
         unregister(agent)
     }
@@ -468,13 +482,8 @@ class NetworkAgentTest {
                 registerNetworkCallback(request, it)
             }
         }
-        createConnectedNetworkAgent().let { (agent, callback) ->
+        createConnectedNetworkAgent(expectedInitSignalStrengthThresholds = thresholds).let {
-            callback.expectAvailableThenValidatedCallbacks(agent.network)
+            (agent, callback) ->
-            agent.expectCallback<OnSignalStrengthThresholdsUpdated>().let {
-                assertArrayEquals(it.thresholds, thresholds)
-            }
-            agent.expectNoInternetValidationStatus()
-
             // Send signal strength and check that the callbacks are called appropriately.
             val nc = NetworkCapabilities(agent.nc)
             nc.setSignalStrength(20)
@@ -483,21 +492,21 @@ class NetworkAgentTest {
 
             nc.setSignalStrength(40)
             agent.sendNetworkCapabilities(nc)
-            callbacks[0].expectAvailableCallbacks(agent.network)
+            callbacks[0].expectAvailableCallbacks(agent.network!!)
             callbacks[1].assertNoCallback(NO_CALLBACK_TIMEOUT)
             callbacks[2].assertNoCallback(NO_CALLBACK_TIMEOUT)
 
             nc.setSignalStrength(80)
             agent.sendNetworkCapabilities(nc)
-            callbacks[0].expectCapabilitiesThat(agent.network) { it.signalStrength == 80 }
+            callbacks[0].expectCapabilitiesThat(agent.network!!) { it.signalStrength == 80 }
-            callbacks[1].expectAvailableCallbacks(agent.network)
+            callbacks[1].expectAvailableCallbacks(agent.network!!)
-            callbacks[2].expectAvailableCallbacks(agent.network)
+            callbacks[2].expectAvailableCallbacks(agent.network!!)
 
             nc.setSignalStrength(55)
             agent.sendNetworkCapabilities(nc)
-            callbacks[0].expectCapabilitiesThat(agent.network) { it.signalStrength == 55 }
+            callbacks[0].expectCapabilitiesThat(agent.network!!) { it.signalStrength == 55 }
-            callbacks[1].expectCapabilitiesThat(agent.network) { it.signalStrength == 55 }
+            callbacks[1].expectCapabilitiesThat(agent.network!!) { it.signalStrength == 55 }
-            callbacks[2].expectCallback<Lost>(agent.network)
+            callbacks[2].expectCallback<Lost>(agent.network!!)
         }
         callbacks.forEach {
             mCM.unregisterNetworkCallback(it)
@@ -546,20 +555,17 @@ class NetworkAgentTest {
 
     @Test
     fun testSendUpdates(): Unit = createConnectedNetworkAgent().let { (agent, callback) ->
-        callback.expectAvailableThenValidatedCallbacks(agent.network)
-        agent.expectEmptySignalStrengths()
-        agent.expectNoInternetValidationStatus()
         val ifaceName = "adhocIface"
         val lp = LinkProperties(agent.lp)
         lp.setInterfaceName(ifaceName)
         agent.sendLinkProperties(lp)
-        callback.expectLinkPropertiesThat(agent.network) {
+        callback.expectLinkPropertiesThat(agent.network!!) {
             it.getInterfaceName() == ifaceName
         }
         val nc = NetworkCapabilities(agent.nc)
         nc.addCapability(NET_CAPABILITY_NOT_METERED)
         agent.sendNetworkCapabilities(nc)
-        callback.expectCapabilitiesThat(agent.network) {
+        callback.expectCapabilitiesThat(agent.network!!) {
             it.hasCapability(NET_CAPABILITY_NOT_METERED)
         }
     }
@@ -568,44 +574,22 @@ class NetworkAgentTest {
     fun testSendScore() {
         // This test will create two networks and check that the one with the stronger
         // score wins out for a request that matches them both.
-        // First create requests to make sure both networks are kept up, using the
-        // specifier so they are specific to each network
-        val name1 = UUID.randomUUID().toString()
-        val name2 = UUID.randomUUID().toString()
-        val request1 = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(name1))
-                .build()
-        val request2 = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(name2))
-                .build()
-        val callback1 = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        val callback2 = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        requestNetwork(request1, callback1)
-        requestNetwork(request2, callback2)
 
-        // Then file the interesting request
+        // File the interesting request
-        val request = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .build()
         val callback = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        requestNetwork(request, callback)
+        requestNetwork(makeTestNetworkRequest(), callback)
 
-        // Connect the first Network
+        // Connect the first Network, with an unused callback that kept the network up.
-        createConnectedNetworkAgent(name = name1).let { (agent1, _) ->
+        val (agent1, _) = createConnectedNetworkAgent()
-            callback.expectAvailableThenValidatedCallbacks(agent1.network)
+        callback.expectAvailableThenValidatedCallbacks(agent1.network!!)
         // If using the int ranking, agent1 must be upgraded to a better score so that there is
         // no ambiguity when agent2 connects that agent1 is still better. If using policy
         // ranking, this is not necessary.
         agent1.sendNetworkScore(NetworkScore.Builder().setLegacyInt(BETTER_NETWORK_SCORE)
                 .build())
-            // Connect the second agent
+
-            createConnectedNetworkAgent(name = name2).let { (agent2, _) ->
+        // Connect the second agent.
-                agent2.markConnected()
+        val (agent2, _) = createConnectedNetworkAgent()
         // The callback should not see anything yet. With int ranking, agent1 was upgraded
         // to a stronger score beforehand. With policy ranking, agent1 is preferred by
         // virtue of already satisfying the request.
@@ -615,9 +599,7 @@ class NetworkAgentTest {
                 .setLegacyInt(WORSE_NETWORK_SCORE)
                 .setExiting(true)
                 .build())
-                callback.expectCallback<Available>(agent2.network)
+        callback.expectCallback<Available>(agent2.network!!)
-            }
-        }
 
         // tearDown() will unregister the requests and agents
     }
@@ -658,7 +640,7 @@ class NetworkAgentTest {
         callback.expectAvailableThenValidatedCallbacks(agent.network!!)
 
         // Check that the default network's transport is propagated to the VPN.
-        var vpnNc = mCM.getNetworkCapabilities(agent.network)
+        var vpnNc = mCM.getNetworkCapabilities(agent.network!!)
         assertNotNull(vpnNc)
         assertEquals(VpnManager.TYPE_VPN_SERVICE,
                 (vpnNc.transportInfo as VpnTransportInfo).type)
@@ -690,7 +672,7 @@ class NetworkAgentTest {
         // This is not very accurate because the test does not control the capabilities of the
         // underlying networks, and because not congested, not roaming, and not suspended are the
         // default anyway. It's still useful as an extra check though.
-        vpnNc = mCM.getNetworkCapabilities(agent.network)
+        vpnNc = mCM.getNetworkCapabilities(agent.network!!)
         for (cap in listOf(NET_CAPABILITY_NOT_CONGESTED,
                 NET_CAPABILITY_NOT_ROAMING,
                 NET_CAPABILITY_NOT_SUSPENDED)) {
@@ -701,7 +683,7 @@ class NetworkAgentTest {
         }
 
         unregister(agent)
-        callback.expectCallback<Lost>(agent.network)
+        callback.expectCallback<Lost>(agent.network!!)
     }
 
     private fun unregister(agent: TestableNetworkAgent) {
@@ -789,33 +771,15 @@ class NetworkAgentTest {
     fun testTemporarilyUnmeteredCapability() {
         // This test will create a networks with/without NET_CAPABILITY_TEMPORARILY_NOT_METERED
         // and check that the callback reflects the capability changes.
-        // First create a request to make sure the network is kept up
-        val request1 = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .build()
-        val callback1 = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS).also {
-            registerNetworkCallback(request1, it)
-        }
-        requestNetwork(request1, callback1)
-
-        // Then file the interesting request
-        val request = NetworkRequest.Builder()
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .build()
-        val callback = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        requestNetwork(request, callback)
 
         // Connect the network
-        createConnectedNetworkAgent().let { (agent, _) ->
+        val (agent, callback) = createConnectedNetworkAgent()
-            callback.expectAvailableThenValidatedCallbacks(agent.network)
 
         // Send TEMP_NOT_METERED and check that the callback is called appropriately.
         val nc1 = NetworkCapabilities(agent.nc)
                 .addCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED)
         agent.sendNetworkCapabilities(nc1)
-            callback.expectCapabilitiesThat(agent.network) {
+        callback.expectCapabilitiesThat(agent.network!!) {
             it.hasCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED)
         }
 
@@ -823,10 +787,9 @@ class NetworkAgentTest {
         val nc2 = NetworkCapabilities(agent.nc)
                 .removeCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED)
         agent.sendNetworkCapabilities(nc2)
-            callback.expectCapabilitiesThat(agent.network) {
+        callback.expectCapabilitiesThat(agent.network!!) {
             !it.hasCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED)
         }
-        }
 
         // tearDown() will unregister the requests and agents
     }
@@ -838,88 +801,137 @@ class NetworkAgentTest {
         // score wins out for a request that matches them both. And the weaker agent will
         // be disconnected after customized linger duration.
 
-        // Connect the first Network
+        // Request the first Network, with a request that could moved to agentStronger in order to
-        val name1 = UUID.randomUUID().toString()
+        // make agentWeaker linger later.
-        val name2 = UUID.randomUUID().toString()
+        val specifierWeaker = UUID.randomUUID().toString()
-        val (agent1, callback) = createConnectedNetworkAgent(name = name1)
+        val specifierStronger = UUID.randomUUID().toString()
-        callback.expectAvailableThenValidatedCallbacks(agent1.network!!)
+        val commonCallback = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        // Downgrade agent1 to a worse score so that there is no ambiguity when
+        requestNetwork(makeTestNetworkRequest(), commonCallback)
-        // agent2 connects.
+        val agentWeaker = createNetworkAgent(specifier = specifierWeaker)
-        agent1.sendNetworkScore(NetworkScore.Builder().setLegacyInt(WORSE_NETWORK_SCORE)
+        agentWeaker.register()
+        agentWeaker.markConnected()
+        commonCallback.expectAvailableThenValidatedCallbacks(agentWeaker.network!!)
+        // Downgrade agentWeaker to a worse score so that there is no ambiguity when
+        // agentStronger connects.
+        agentWeaker.sendNetworkScore(NetworkScore.Builder().setLegacyInt(WORSE_NETWORK_SCORE)
                 .setExiting(true).build())
 
         // Verify invalid linger duration cannot be set.
         assertFailsWith<IllegalArgumentException> {
-            agent1.setLingerDuration(Duration.ofMillis(-1))
+            agentWeaker.setLingerDuration(Duration.ofMillis(-1))
         }
-        assertFailsWith<IllegalArgumentException> { agent1.setLingerDuration(Duration.ZERO) }
+        assertFailsWith<IllegalArgumentException> { agentWeaker.setLingerDuration(Duration.ZERO) }
         assertFailsWith<IllegalArgumentException> {
-            agent1.setLingerDuration(Duration.ofMillis(Integer.MIN_VALUE.toLong()))
+            agentWeaker.setLingerDuration(Duration.ofMillis(Integer.MIN_VALUE.toLong()))
         }
         assertFailsWith<IllegalArgumentException> {
-            agent1.setLingerDuration(Duration.ofMillis(Integer.MAX_VALUE.toLong() + 1))
+            agentWeaker.setLingerDuration(Duration.ofMillis(Integer.MAX_VALUE.toLong() + 1))
         }
         assertFailsWith<IllegalArgumentException> {
-            agent1.setLingerDuration(Duration.ofMillis(
+            agentWeaker.setLingerDuration(Duration.ofMillis(
                     NetworkAgent.MIN_LINGER_TIMER_MS.toLong() - 1))
         }
         // Verify valid linger timer can be set, but it should not take effect since the network
         // is still needed.
-        agent1.setLingerDuration(Duration.ofMillis(Integer.MAX_VALUE.toLong()))
+        agentWeaker.setLingerDuration(Duration.ofMillis(Integer.MAX_VALUE.toLong()))
-        callback.assertNoCallback(NO_CALLBACK_TIMEOUT)
+        commonCallback.assertNoCallback(NO_CALLBACK_TIMEOUT)
         // Set to the value we want to verify the functionality.
-        agent1.setLingerDuration(Duration.ofMillis(NetworkAgent.MIN_LINGER_TIMER_MS.toLong()))
+        agentWeaker.setLingerDuration(Duration.ofMillis(NetworkAgent.MIN_LINGER_TIMER_MS.toLong()))
-        // Make a listener which can observe agent1 lost later.
+        // Make a listener which can observe agentWeaker lost later.
         val callbackWeaker = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
         registerNetworkCallback(NetworkRequest.Builder()
                 .clearCapabilities()
                 .addTransportType(TRANSPORT_TEST)
-                .setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(name1))
+                .setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(specifierWeaker))
                 .build(), callbackWeaker)
-        callbackWeaker.expectAvailableCallbacks(agent1.network!!)
+        callbackWeaker.expectAvailableCallbacks(agentWeaker.network!!)
 
-        // Connect the second agent with a score better than agent1. Verify the callback for
+        // Connect the agentStronger with a score better than agentWeaker. Verify the callback for
-        // agent1 sees the linger expiry while the callback for both sees the winner.
+        // agentWeaker sees the linger expiry while the callback for both sees the winner.
         // Record linger start timestamp prior to send score to prevent possible race, the actual
         // timestamp should be slightly late than this since the service handles update
         // network score asynchronously.
         val lingerStart = SystemClock.elapsedRealtime()
-        val agent2 = createNetworkAgent(name = name2)
+        val agentStronger = createNetworkAgent(specifier = specifierStronger)
-        agent2.register()
+        agentStronger.register()
-        agent2.markConnected()
+        agentStronger.markConnected()
-        callback.expectAvailableCallbacks(agent2.network!!)
+        commonCallback.expectAvailableCallbacks(agentStronger.network!!)
-        callbackWeaker.expectCallback<Losing>(agent1.network!!)
+        callbackWeaker.expectCallback<Losing>(agentWeaker.network!!)
         val expectedRemainingLingerDuration = lingerStart +
                 NetworkAgent.MIN_LINGER_TIMER_MS.toLong() - SystemClock.elapsedRealtime()
         // If the available callback is too late. The remaining duration will be reduced.
         assertTrue(expectedRemainingLingerDuration > 0,
                 "expected remaining linger duration is $expectedRemainingLingerDuration")
         callbackWeaker.assertNoCallback(expectedRemainingLingerDuration)
-        callbackWeaker.expectCallback<Lost>(agent1.network!!)
+        callbackWeaker.expectCallback<Lost>(agentWeaker.network!!)
     }
 
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.R)
     fun testSetSubscriberId() {
-        val name = "TEST-AGENT"
         val imsi = UUID.randomUUID().toString()
         val config = NetworkAgentConfig.Builder().setSubscriberId(imsi).build()
 
-        val request: NetworkRequest = NetworkRequest.Builder()
+        val (agent, _) = createConnectedNetworkAgent(initialConfig = config)
-                .clearCapabilities()
-                .addTransportType(TRANSPORT_TEST)
-                .setNetworkSpecifier(CompatUtil.makeEthernetNetworkSpecifier(name))
-                .build()
-        val callback = TestableNetworkCallback(timeoutMs = DEFAULT_TIMEOUT_MS)
-        requestNetwork(request, callback)
-
-        val agent = createNetworkAgent(name = name, initialConfig = config)
-        agent.register()
-        agent.markConnected()
-        callback.expectAvailableThenValidatedCallbacks(agent.network!!)
         val snapshots = runWithShellPermissionIdentity(ThrowingSupplier {
                 mCM!!.allNetworkStateSnapshots }, NETWORK_SETTINGS)
         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
+    }
 }