Merge changes from topic "deprecate_connectivity_action_in_tethering"

* changes:
  Tethering: deprecate CONNECTIVITY_ACTION on U+ device
  Test: add tests to testChooseDunUpstreamByAutomaticMode_*
  TetheringTest: separate setup func from chooseDunUpstreamTestCommon
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index e1b7016..e48019c 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -1203,6 +1203,9 @@
         }
 
         private void handleConnectivityAction(Intent intent) {
+            // CONNECTIVITY_ACTION is not handled since U+ device.
+            if (SdkLevel.isAtLeastU()) return;
+
             final NetworkInfo networkInfo =
                     (NetworkInfo) intent.getParcelableExtra(EXTRA_NETWORK_INFO);
             if (networkInfo == null
@@ -2034,6 +2037,11 @@
                     // broadcasts that result in being passed a
                     // TetherMainSM.CMD_UPSTREAM_CHANGED.
                     handleNewUpstreamNetworkState(null);
+
+                    if (SdkLevel.isAtLeastU()) {
+                        // Need to try DUN immediately if Wi-Fi goes down.
+                        chooseUpstreamType(true);
+                    }
                     break;
                 default:
                     mLog.e("Unknown arg1 value: " + arg1);
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index a8d886b..7f982f3 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -82,6 +82,8 @@
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeFalse;
@@ -179,6 +181,7 @@
 import android.util.ArraySet;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
 
@@ -1337,6 +1340,131 @@
         verifyDisableTryCellWhenTetheringStop(inOrder);
     }
 
+    private void verifyWifiUpstreamAndUnregisterDunCallback(@NonNull final InOrder inOrder,
+            @NonNull final TestNetworkAgent wifi,
+            @NonNull final NetworkCallback currentDunCallack) throws Exception {
+        assertNotNull(currentDunCallack);
+
+        inOrder.verify(mUpstreamNetworkMonitor).setTryCell(false);
+        inOrder.verify(mCm).unregisterNetworkCallback(eq(currentDunCallack));
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(wifi.networkId);
+        inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());
+    }
+
+    @Nullable
+    private NetworkCallback verifyDunUpstream(@NonNull final InOrder inOrder,
+            @NonNull final TestNetworkAgent dun, final boolean needToRequestNetwork)
+            throws Exception {
+        inOrder.verify(mUpstreamNetworkMonitor).setTryCell(true);
+        ArgumentCaptor<NetworkCallback> captor = ArgumentCaptor.forClass(NetworkCallback.class);
+        NetworkCallback dunNetworkCallback = null;
+        if (needToRequestNetwork) {
+            inOrder.verify(mCm).requestNetwork(any(), eq(0), eq(TYPE_MOBILE_DUN), any(),
+                    captor.capture());
+            dunNetworkCallback = captor.getValue();
+        }
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(null);
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        dun.fakeConnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(dun.networkId);
+
+        if (needToRequestNetwork) {
+            assertNotNull(dunNetworkCallback);
+        } else {
+            assertNull(dunNetworkCallback);
+        }
+
+        return dunNetworkCallback;
+    }
+
+    // Overall test coverage:
+    // - verifyChooseDunUpstreamByAutomaticMode: common, test#1, test#2
+    // - testChooseDunUpstreamByAutomaticMode_defaultNetworkWifi: test#3, test#4
+    // - testChooseDunUpstreamByAutomaticMode_loseDefaultNetworkWifi: test#5
+    // - testChooseDunUpstreamByAutomaticMode_defaultNetworkCell: test#5, test#7
+    // - testChooseDunUpstreamByAutomaticMode_loseAndRegainDun: test#8
+    // - testChooseDunUpstreamByAutomaticMode_switchDefaultFromWifiToCell: test#9, test#10
+    //
+    // Overall test cases:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |       |       |       |   -   | --+
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |       |   V   |       |   -   |   |
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |       |   V   |   O   |  Dun  |   +-- chooseDunUpstreamTestCommon
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |   V   |   O   |   O   |  WiFi |   |
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |   V   |   O   |       |  WiFi | --+
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   1   +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   2   +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   3   |   V   |   O   |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |   4   |   V   |       |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |   5   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   6   |       |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   7   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |       |       |       |   -   |
+    // |   8   +-------+-------+-------+-------+
+    // |       |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |   V   |       |   O   |  WiFi |
+    // |   9   +-------+-------+-------+-------+
+    // |       |   V   |       |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   10  +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
+    // Annotation:
+    // 1. "V" means that the given network is connected and it is default network.
+    // 2. "O" means that the given network is connected and it is not default network.
+    //
+
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |       |       |       |   -   | --+
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |       |   V   |       |   -   |   |
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |       |   V   |   O   |  Dun  |   +-- chooseDunUpstreamTestCommon
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |   V   |   O   |   O   |  WiFi |   |
+    // +-------+-------+-------+-------+-------+   |
+    // |   -   |   V   |   O   |       |  WiFi | --+
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   1   +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   2   +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
     private void verifyChooseDunUpstreamByAutomaticMode(boolean configAutomatic) throws Exception {
         // Enable automatic upstream selection.
         TestNetworkAgent mobile = new TestNetworkAgent(mCm, buildMobileDualStackUpstreamState());
@@ -1345,20 +1473,14 @@
         InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
         chooseDunUpstreamTestCommon(configAutomatic, inOrder, mobile, wifi, dun);
 
-        // When default network switch to mobile and wifi is connected (may have low signal),
+        // [1] When default network switch to mobile and wifi is connected (may have low signal),
         // automatic mode would request dun again and choose it as upstream.
         mCm.makeDefaultNetwork(mobile, CALLBACKS_FIRST);
         mLooper.dispatchAll();
-        inOrder.verify(mUpstreamNetworkMonitor).setTryCell(true);
-        ArgumentCaptor<NetworkCallback> captor = ArgumentCaptor.forClass(NetworkCallback.class);
-        inOrder.verify(mCm).requestNetwork(any(), eq(0), eq(TYPE_MOBILE_DUN), any(), any());
-        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(null);
-        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
-        dun.fakeConnect(CALLBACKS_FIRST, doDispatchAll);
-        mLooper.dispatchAll();
-        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(dun.networkId);
+        verifyDunUpstream(inOrder, dun, true /* needToRequestNetwork */);
 
-        // Lose and regain upstream again.
+        // [2] Lose and regain upstream again.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
         dun.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
         mLooper.dispatchAll();
         inOrder.verify(mUpstreamNetworkMonitor).setTryCell(true);
@@ -1376,12 +1498,245 @@
         verifyChooseDunUpstreamByAutomaticMode(true /* configAutomatic */);
     }
 
+    // testChooseDunUpstreamByAutomaticMode_* doesn't verify configAutomatic:false because no
+    // matter |configAutomatic| set to true or false, the result always be automatic mode. We
+    // just need one test to make sure this behavior. Don't need to test this configuration
+    // in all tests.
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.TIRAMISU)
     public void testChooseDunUpstreamByAutomaticModeWithConfigDisabled() throws Exception {
         verifyChooseDunUpstreamByAutomaticMode(false /* configAutomatic */);
     }
 
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   3   |   V   |   O   |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |   4   |   V   |       |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    //
+    // See verifyChooseDunUpstreamByAutomaticMode for the annotation.
+    //
+    @Test
+    public void testChooseDunUpstreamByAutomaticMode_defaultNetworkWifi() throws Exception {
+        TestNetworkAgent mobile = new TestNetworkAgent(mCm, buildMobileDualStackUpstreamState());
+        TestNetworkAgent wifi = new TestNetworkAgent(mCm, buildWifiUpstreamState());
+        TestNetworkAgent dun = new TestNetworkAgent(mCm, buildDunUpstreamState());
+        final InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
+        final NetworkCallback dunNetworkCallback1 = setupDunUpstreamTest(
+                true /* configAutomatic */, inOrder);
+
+        // When wifi connected, unregister dun request and choose wifi as upstream.
+        wifi.fakeConnect();
+        mCm.makeDefaultNetwork(wifi, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        verifyWifiUpstreamAndUnregisterDunCallback(inOrder, wifi, dunNetworkCallback1);
+
+        // When default network switch to mobile and wifi is connected (may have low signal),
+        // automatic mode would request dun again and choose it as upstream.
+        mCm.makeDefaultNetwork(mobile, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        final NetworkCallback dunNetworkCallback2 =
+                verifyDunUpstream(inOrder, dun, true /* needToRequestNetwork */);
+
+        // [3] When default network switch to wifi and mobile is still connected,
+        // unregister dun request and choose wifi as upstream.
+        mCm.makeDefaultNetwork(wifi, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        verifyWifiUpstreamAndUnregisterDunCallback(inOrder, wifi, dunNetworkCallback2);
+
+        // [4] When mobile is disconnected, keep wifi as upstream.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        mobile.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());
+
+        verifyDisableTryCellWhenTetheringStop(inOrder);
+    }
+
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |   V   |       |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |   5   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
+    // See verifyChooseDunUpstreamByAutomaticMode for the annotation.
+    //
+    @Test
+    public void testChooseDunUpstreamByAutomaticMode_loseDefaultNetworkWifi() throws Exception {
+        TestNetworkAgent wifi = new TestNetworkAgent(mCm, buildWifiUpstreamState());
+        TestNetworkAgent dun = new TestNetworkAgent(mCm, buildDunUpstreamState());
+        final InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
+        final NetworkCallback dunNetworkCallback = setupDunUpstreamTest(
+                true /* configAutomatic */, inOrder);
+
+        // When wifi connected, unregister dun request and choose wifi as upstream.
+        wifi.fakeConnect();
+        mCm.makeDefaultNetwork(wifi, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        verifyWifiUpstreamAndUnregisterDunCallback(inOrder, wifi, dunNetworkCallback);
+
+        // [5] When wifi is disconnected, automatic mode would request dun again and choose it
+        // as upstream.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        mCm.makeDefaultNetwork(null, CALLBACKS_FIRST, doDispatchAll);
+        wifi.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        verifyDunUpstream(inOrder, dun, true /* needToRequestNetwork */);
+
+        verifyDisableTryCellWhenTetheringStop(inOrder);
+    }
+
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   6   |       |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |   7   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
+    // See verifyChooseDunUpstreamByAutomaticMode for the annotation.
+    //
+    @Test
+    public void testChooseDunUpstreamByAutomaticMode_defaultNetworkCell() throws Exception {
+        TestNetworkAgent mobile = new TestNetworkAgent(mCm, buildMobileDualStackUpstreamState());
+        TestNetworkAgent dun = new TestNetworkAgent(mCm, buildDunUpstreamState());
+        final InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
+        setupDunUpstreamTest(true /* configAutomatic */, inOrder);
+
+        // Pretend dun connected and expect choose dun as upstream.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        dun.fakeConnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(dun.networkId);
+
+        // [6] When mobile is connected and default network switch to mobile, keep dun as upstream.
+        mobile.fakeConnect();
+        mCm.makeDefaultNetwork(mobile, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());
+
+        // [7] When mobile is disconnected, keep dun as upstream.
+        mCm.makeDefaultNetwork(null, CALLBACKS_FIRST, doDispatchAll);
+        mobile.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());
+
+        verifyDisableTryCellWhenTetheringStop(inOrder);
+    }
+
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |       |       |       |   -   |
+    // |   8   +-------+-------+-------+-------+
+    // |       |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
+    // See verifyChooseDunUpstreamByAutomaticMode for the annotation.
+    //
+    @Test
+    public void testChooseDunUpstreamByAutomaticMode_loseAndRegainDun() throws Exception {
+        TestNetworkAgent dun = new TestNetworkAgent(mCm, buildDunUpstreamState());
+        final InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
+        setupDunUpstreamTest(true /* configAutomatic */, inOrder);
+
+        // Pretend dun connected and expect choose dun as upstream.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        dun.fakeConnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(dun.networkId);
+
+        // [8] Lose and regain upstream again.
+        dun.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        verifyDunUpstream(inOrder, dun, false /* needToRequestNetwork */);
+
+        verifyDisableTryCellWhenTetheringStop(inOrder);
+    }
+
+    // Test case:
+    // +-------+-------+-------+-------+-------+
+    // | Test  | WiFi  | Cellu |  Dun  | Expec |
+    // | Case  |       | alr   |       | ted   |
+    // |   #   |       |       |       | Upstr |
+    // |       |       |       |       | eam   |
+    // +-------+-------+-------+-------+-------+
+    // |   -   |       |       |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    // |       |   V   |       |   O   |  WiFi |
+    // |   9   +-------+-------+-------+-------+
+    // |       |   V   |       |       |  WiFi |
+    // +-------+-------+-------+-------+-------+
+    // |       |   O   |   V   |       |   -   |
+    // |   10  +-------+-------+-------+-------+
+    // |       |   O   |   V   |   O   |  Dun  |
+    // +-------+-------+-------+-------+-------+
+    //
+    // See verifyChooseDunUpstreamByAutomaticMode for the annotation.
+    //
+    @Test
+    public void testChooseDunUpstreamByAutomaticMode_switchDefaultFromWifiToCell()
+            throws Exception {
+        TestNetworkAgent mobile = new TestNetworkAgent(mCm, buildMobileDualStackUpstreamState());
+        TestNetworkAgent wifi = new TestNetworkAgent(mCm, buildWifiUpstreamState());
+        TestNetworkAgent dun = new TestNetworkAgent(mCm, buildDunUpstreamState());
+        final InOrder inOrder = inOrder(mCm, mUpstreamNetworkMonitor);
+        final NetworkCallback dunNetworkCallback = setupDunUpstreamTest(
+                true /* configAutomatic */, inOrder);
+
+        // Pretend dun connected and expect choose dun as upstream.
+        final Runnable doDispatchAll = () -> mLooper.dispatchAll();
+        dun.fakeConnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(dun.networkId);
+
+        // [9] When wifi is connected and default network switch to wifi, unregister dun request
+        // and choose wifi as upstream. When dun is disconnected, keep wifi as upstream.
+        wifi.fakeConnect();
+        mCm.makeDefaultNetwork(wifi, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        verifyWifiUpstreamAndUnregisterDunCallback(inOrder, wifi, dunNetworkCallback);
+        dun.fakeDisconnect(CALLBACKS_FIRST, doDispatchAll);
+        mLooper.dispatchAll();
+        inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());
+
+        // [10] When mobile and mobile are connected and default network switch to mobile
+        // (may have low signal), automatic mode would request dun again and choose it as
+        // upstream.
+        mobile.fakeConnect();
+        mCm.makeDefaultNetwork(mobile, CALLBACKS_FIRST);
+        mLooper.dispatchAll();
+        verifyDunUpstream(inOrder, dun, true /* needToRequestNetwork */);
+
+        verifyDisableTryCellWhenTetheringStop(inOrder);
+    }
+
     @Test
     @IgnoreAfter(Build.VERSION_CODES.TIRAMISU)
     public void testChooseDunUpstreamByLegacyMode() throws Exception {
@@ -1425,8 +1780,7 @@
         verifyDisableTryCellWhenTetheringStop(inOrder);
     }
 
-    private void chooseDunUpstreamTestCommon(final boolean automatic, InOrder inOrder,
-            TestNetworkAgent mobile, TestNetworkAgent wifi, TestNetworkAgent dun) throws Exception {
+    private NetworkCallback setupDunUpstreamTest(final boolean automatic, InOrder inOrder) {
         when(mResources.getBoolean(R.bool.config_tether_upstream_automatic)).thenReturn(automatic);
         when(mTelephonyManager.isTetheringApnRequired()).thenReturn(true);
         sendConfigurationChanged();
@@ -1439,8 +1793,14 @@
         inOrder.verify(mUpstreamNetworkMonitor).setTryCell(true);
         ArgumentCaptor<NetworkCallback> captor = ArgumentCaptor.forClass(NetworkCallback.class);
         inOrder.verify(mCm).requestNetwork(any(), eq(0), eq(TYPE_MOBILE_DUN), any(),
-                captor.capture());
-        final NetworkCallback dunNetworkCallback1 = captor.getValue();
+                captor.capture() /* DUN network callback */);
+
+        return captor.getValue();
+    }
+
+    private void chooseDunUpstreamTestCommon(final boolean automatic, InOrder inOrder,
+            TestNetworkAgent mobile, TestNetworkAgent wifi, TestNetworkAgent dun) throws Exception {
+        final NetworkCallback dunNetworkCallback = setupDunUpstreamTest(automatic, inOrder);
 
         // Pretend cellular connected and expect the upstream to be set.
         mobile.fakeConnect();
@@ -1458,9 +1818,7 @@
         wifi.fakeConnect();
         mCm.makeDefaultNetwork(wifi, CALLBACKS_FIRST);
         mLooper.dispatchAll();
-        inOrder.verify(mUpstreamNetworkMonitor).setTryCell(false);
-        inOrder.verify(mCm).unregisterNetworkCallback(eq(dunNetworkCallback1));
-        inOrder.verify(mUpstreamNetworkMonitor).setCurrentUpstream(wifi.networkId);
+        verifyWifiUpstreamAndUnregisterDunCallback(inOrder, wifi, dunNetworkCallback);
         dun.fakeDisconnect(BROADCAST_FIRST, doDispatchAll);
         mLooper.dispatchAll();
         inOrder.verify(mUpstreamNetworkMonitor, never()).setCurrentUpstream(any());