diff --git a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala b/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
index 98fe6cb301f52..39eb8b183488f 100644
--- a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
+++ b/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
@@ -19,16 +19,19 @@ package org.apache.spark.streaming.mqtt
 
 import java.net.{URI, ServerSocket}
 
+import scala.concurrent.duration._
+
 import org.apache.activemq.broker.{TransportConnector, BrokerService}
-import org.apache.spark.util.Utils
+import org.eclipse.paho.client.mqttv3._
+import org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence
+
 import org.scalatest.{BeforeAndAfter, FunSuite}
 import org.scalatest.concurrent.Eventually
-import scala.concurrent.duration._
+
 import org.apache.spark.streaming.{Milliseconds, StreamingContext}
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming.dstream.ReceiverInputDStream
-import org.eclipse.paho.client.mqttv3._
-import org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence
+import org.apache.spark.util.Utils
 
 class MQTTStreamSuite extends FunSuite with Eventually with BeforeAndAfter {
 
@@ -38,8 +41,9 @@ class MQTTStreamSuite extends FunSuite with Eventually with BeforeAndAfter {
   private val freePort = findFreePort()
   private val brokerUri = "//localhost:" + freePort
   private val topic = "def"
-  private var ssc: StreamingContext = _
   private val persistenceDir = Utils.createTempDir()
+
+  private var ssc: StreamingContext = _
   private var broker: BrokerService = _
   private var connector: TransportConnector = _
 
@@ -115,8 +119,9 @@ class MQTTStreamSuite extends FunSuite with Eventually with BeforeAndAfter {
         val message: MqttMessage = new MqttMessage(data.getBytes("utf-8"))
         message.setQos(1)
         message.setRetained(true)
-        for (i <- 0 to 100)
+        for (i <- 0 to 100) {
           msgTopic.publish(message)
+        }
       }
     } finally {
       client.disconnect()