Add CTS for ConnectivityManager#setVpnDefaultForUids()

This test checks
- If the NullPointerException will be thrown or not when the
  given uid ragnes is null.
- If the SecurityException will be thrown or not when the caller
  doesn't have related permission.

Bug: 231749077
Test: atest CtsNetTestCases
      atest CtsNetTestCasesLatestSdk
Change-Id: Ia1e625bc1f791ee9928ba00d76af9979ba52b2db
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index 7624f9c..3093243 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -233,6 +233,7 @@
 import java.util.Objects;
 import java.util.Random;
 import java.util.Set;
+import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
@@ -2469,6 +2470,17 @@
         runWithShellPermissionIdentity(() -> doTestBlockedStatusCallback(), NETWORK_SETTINGS);
     }
 
+    @Test
+    public void testSetVpnDefaultForUids() {
+        assumeTrue(TestUtils.shouldTestUApis());
+        final String session = UUID.randomUUID().toString();
+        assertThrows(NullPointerException.class, () -> mCm.setVpnDefaultForUids(session, null));
+        assertThrows(SecurityException.class,
+                () -> mCm.setVpnDefaultForUids(session, new ArraySet<>()));
+        // For testing the complete behavior of setVpnDefaultForUids(), please refer to
+        // HostsideVpnTests.
+    }
+
     private void doTestLegacyLockdownEnabled() throws Exception {
         NetworkInfo info = mCm.getActiveNetworkInfo();
         assertNotNull(info);