diff --git a/Tethering/common/TetheringLib/Android.bp b/Tethering/common/TetheringLib/Android.bp
index f652772..6e64570 100644
--- a/Tethering/common/TetheringLib/Android.bp
+++ b/Tethering/common/TetheringLib/Android.bp
@@ -22,7 +22,19 @@
     defaults: ["framework-module-defaults"],
     impl_library_visibility: [
         "//packages/modules/Connectivity/Tethering:__subpackages__",
+
+        // Using for test only
+        "//cts/tests/netlegacy22.api",
+        "//external/sl4a:__subpackages__",
+        "//frameworks/base/packages/Connectivity/tests:__subpackages__",
+        "//frameworks/libs/net/common/testutils",
+        "//frameworks/libs/net/common/tests:__subpackages__",
+        "//frameworks/opt/telephony/tests/telephonytests",
+        "//packages/modules/CaptivePortalLogin/tests",
+        "//packages/modules/Connectivity/Tethering/tests:__subpackages__",
         "//packages/modules/Connectivity/tests:__subpackages__",
+        "//packages/modules/NetworkStack/tests:__subpackages__",
+        "//packages/modules/Wifi/service/tests/wifitests",
     ],
 
     srcs: [":framework-tethering-srcs"],
diff --git a/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl b/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl
index cf094aa..77e78bd 100644
--- a/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl
+++ b/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl
@@ -49,4 +49,6 @@
 
     void stopAllTethering(String callerPkg, String callingAttributionTag,
             IIntResultListener receiver);
+
+    void setPreferTestNetworks(boolean prefer, IIntResultListener listener);
 }
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
index 73ab908..65b2650 100644
--- a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -1538,4 +1538,25 @@
                     }
                 }));
     }
+
+    /**
+     * Whether to treat networks that have TRANSPORT_TEST as Tethering upstreams. The effects of
+     * this method apply to any test networks that are already present on the system.
+     *
+     * @throws SecurityException If the caller doesn't have the NETWORK_SETTINGS permission.
+     * @hide
+     */
+    @RequiresPermission(android.Manifest.permission.NETWORK_SETTINGS)
+    public void setPreferTestNetworks(final boolean prefer) {
+        Log.i(TAG, "setPreferTestNetworks caller: " + mContext.getOpPackageName());
+
+        final RequestDispatcher dispatcher = new RequestDispatcher();
+        final int ret = dispatcher.waitForResult((connector, listener) -> {
+            try {
+                connector.setPreferTestNetworks(prefer, listener);
+            } catch (RemoteException e) {
+                throw new IllegalStateException(e);
+            }
+        });
+    }
 }