Suppress log messages in sbt test with two changes:

1. Set akka log level to ERROR before shutting down the actorSystem.
This avoids akka log messages (like Spray) from falling back to INFO
on the Stdout logger
2. Initialize netty to use SLF4J in LocalSparkContext. This ensures that
stack trace thrown during shutdown is handled by SLF4J instead of stdout

core/src/main/scala/spark/SparkEnv.scala

@@ -5,6 +5,7 @@ import serializer.Serializer
 
 import akka.actor.{Actor, ActorRef, Props, ActorSystemImpl, ActorSystem}
 import akka.remote.RemoteActorRefProvider
+import akka.event.{Logging => AkkaLogging}
 
 import spark.broadcast.BroadcastManager
 import spark.storage.BlockManager
@@ -51,6 +52,7 @@ class SparkEnv (
     broadcastManager.stop()
     blockManager.stop()
     blockManager.master.stop()
+    actorSystem.eventStream.setLogLevel(AkkaLogging.ErrorLevel)
     actorSystem.shutdown()
     // Unfortunately Akka's awaitTermination doesn't actually wait for the Netty server to shut
     // down, but let's call it anyway in case it gets fixed in a later release

core/src/main/scala/spark/deploy/LocalSparkCluster.scala

 package spark.deploy
 
 import akka.actor.{ActorRef, Props, Actor, ActorSystem, Terminated}
+import akka.event.{Logging => AkkaLogging}
 
 import spark.deploy.worker.Worker
 import spark.deploy.master.Master
@@ -43,8 +44,11 @@ class LocalSparkCluster(numWorkers: Int, coresPerWorker: Int, memoryPerWorker: I
   def stop() {
     logInfo("Shutting down local Spark cluster.")
     // Stop the workers before the master so they don't get upset that it disconnected
+    workerActorSystems.foreach(_.eventStream.setLogLevel(AkkaLogging.ErrorLevel))
     workerActorSystems.foreach(_.shutdown())
     workerActorSystems.foreach(_.awaitTermination())
+
+    masterActorSystems.foreach(_.eventStream.setLogLevel(AkkaLogging.ErrorLevel))
     masterActorSystems.foreach(_.shutdown())
     masterActorSystems.foreach(_.awaitTermination())
   }

core/src/test/scala/spark/FileServerSuite.scala

@@ -85,7 +85,6 @@ class FileServerSuite extends FunSuite with LocalSparkContext {
       in.close()
       _ * fileVal + _ * fileVal
     }.collect
-    println(result)
     assert(result.toSet === Set((1,200), (2,300), (3,500)))
   }
 

core/src/test/scala/spark/LocalSparkContext.scala

@@ -2,12 +2,21 @@ package spark
 
 import org.scalatest.Suite
 import org.scalatest.BeforeAndAfterEach
+import org.scalatest.BeforeAndAfterAll
+
+import org.jboss.netty.logging.InternalLoggerFactory
+import org.jboss.netty.logging.Slf4JLoggerFactory
 
 /** Manages a local `sc` {@link SparkContext} variable, correctly stopping it after each test. */
-trait LocalSparkContext extends BeforeAndAfterEach { self: Suite =>
+trait LocalSparkContext extends BeforeAndAfterEach with BeforeAndAfterAll { self: Suite =>
 
   @transient var sc: SparkContext = _
 
+  override def beforeAll() {
+    InternalLoggerFactory.setDefaultFactory(new Slf4JLoggerFactory());
+    super.beforeAll()
+  }
+
   override def afterEach() {
     resetSparkContext()
     super.afterEach()