diff --git a/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala b/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala
index 538ae05e4eea1..72427dd6ce4d4 100644
--- a/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala
+++ b/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala
@@ -206,6 +206,7 @@ class KryoSerializer(conf: SparkConf)
         kryo.register(clazz)
       } catch {
         case NonFatal(_) => // do nothing
+        case _: NoClassDefFoundError if Utils.isTesting => // See SPARK-23422.
       }
     }