diff --git a/core/src/test/scala/org/apache/spark/HeartbeatReceiverSuite.scala b/core/src/test/scala/org/apache/spark/HeartbeatReceiverSuite.scala
index 1c87f5c53b177..b705556e54b14 100644
--- a/core/src/test/scala/org/apache/spark/HeartbeatReceiverSuite.scala
+++ b/core/src/test/scala/org/apache/spark/HeartbeatReceiverSuite.scala
@@ -72,6 +72,7 @@ class HeartbeatReceiverSuite
     sc = spy(new SparkContext(conf))
     scheduler = mock(classOf[TaskSchedulerImpl])
     when(sc.taskScheduler).thenReturn(scheduler)
+    when(scheduler.nodeBlacklist).thenReturn(Predef.Set[String]())
     when(scheduler.sc).thenReturn(sc)
     heartbeatReceiverClock = new ManualClock
     heartbeatReceiver = new HeartbeatReceiver(sc, heartbeatReceiverClock)