diff --git a/core/api/src/test/java/org/onosproject/mastership/MastershipServiceAdapter.java b/core/api/src/test/java/org/onosproject/mastership/MastershipServiceAdapter.java
index aff67cd..7db9b38 100644
--- a/core/api/src/test/java/org/onosproject/mastership/MastershipServiceAdapter.java
+++ b/core/api/src/test/java/org/onosproject/mastership/MastershipServiceAdapter.java
@@ -38,7 +38,8 @@
     }
 
     @Override
-    public void relinquishMastership(DeviceId deviceId) {
+    public CompletableFuture<Void> relinquishMastership(DeviceId deviceId) {
+        return null;
     }
 
     @Override