diff --git a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
index 1022b06..f696885 100644
--- a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
+++ b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
@@ -176,6 +176,7 @@
         // tests, turn tethering on and off before running them.
         MyTetheringEventCallback callback = null;
         TestNetworkInterface testIface = null;
+        assumeTrue(sEm != null);
         try {
             // If the physical ethernet interface is available, do nothing.
             if (isInterfaceForTetheringAvailable()) return;