diff --git a/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/provider/DefaultVirtualFlowRuleProviderTest.java b/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/provider/DefaultVirtualFlowRuleProviderTest.java
index 2b010bb..e268f32 100644
--- a/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/provider/DefaultVirtualFlowRuleProviderTest.java
+++ b/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/provider/DefaultVirtualFlowRuleProviderTest.java
@@ -347,7 +347,7 @@
 
         @Override
         public Set<VirtualLink> getVirtualLinks(NetworkId networkId) {
-            return null;
+            return new HashSet<>();
         }
 
         @Override