Adding another unit test to Web UI suite

core/src/main/scala/spark/deploy/master/ui/MasterWebUI.scala

@@ -15,7 +15,7 @@ import spark.ui.JettyUtils._
  * Web UI server for the standalone master.
  */
 private[spark]
-class MasterWebUI(val master: ActorRef, requestedPort: Option[Int]) extends Logging {
+class MasterWebUI(val master: ActorRef, requestedPort: Option[Int] = None) extends Logging {
   implicit val timeout = Duration.create(
     System.getProperty("spark.akka.askTimeout", "10").toLong, "seconds")
   val host = Utils.localHostName()
@@ -33,7 +33,7 @@ class MasterWebUI(val master: ActorRef, requestedPort: Option[Int]) extends Logg
       val (srv, bPort) = JettyUtils.startJettyServer("0.0.0.0", port, handlers)
       server = Some(srv)
       boundPort = Some(bPort)
-      logInfo("Started Master web UI at http://%s:%d".format(host, boundPort))
+      logInfo("Started Master web UI at http://%s:%d".format(host, boundPort.get))
     } catch {
       case e: Exception =>
         logError("Failed to create Master JettyUtils", e)

core/src/main/scala/spark/ui/JettyUtils.scala

@@ -62,7 +62,7 @@ private[spark] object JettyUtils extends Logging {
     }
   }
 
-  /** Creates a handler for serving files from a static directory. */
+  /** Creates a handler for serving files from a static directory */
   def createStaticHandler(resourceBase: String): ResourceHandler = {
     val staticHandler = new ResourceHandler
     Option(getClass.getClassLoader.getResource(resourceBase)) match {

core/src/test/scala/spark/ui/UISuite.scala

@@ -2,14 +2,28 @@ package spark.ui
 
 import org.scalatest.FunSuite
 import org.eclipse.jetty.server.Server
+import util.{Try, Success, Failure}
+import java.net.ServerSocket
 
 class UISuite extends FunSuite {
   test("jetty port increases under contention") {
     val startPort = 33333
     val server = new Server(startPort)
     server.start()
-    val (jettyServer, boundPort) = JettyUtils.startJettyServer("localhost", startPort, Seq())
-    assert(boundPort === startPort + 1)
+    val (jettyServer1, boundPort1) = JettyUtils.startJettyServer("localhost", startPort, Seq())
+    val (jettyServer2, boundPort2) = JettyUtils.startJettyServer("localhost", startPort, Seq())
+
+    assert(boundPort1 === startPort + 1)
+    assert(boundPort2 === startPort + 2)
   }
 
+  test("jetty binds to port 0 correctly") {
+    val (jettyServer, boundPort) = JettyUtils.startJettyServer("localhost", 0, Seq())
+    assert(jettyServer.getState === "STARTED")
+    assert(boundPort != 0)
+    Try {new ServerSocket(boundPort)} match {
+      case Success(s) => fail("Port %s doesn't seem used by jetty server".format(boundPort))
+      case Failure(e) =>
+    }
+  }
 }