[Spark-3490] Disable SparkUI for tests

We currently open many ephemeral ports during the tests, and as a result we occasionally can't bind to new ones. This has caused the `DriverSuite` and the `SparkSubmitSuite` to fail intermittently.

By disabling the `SparkUI` when it's not needed, we already cut down on the number of ports opened significantly, on the order of the number of `SparkContexts` ever created. We must keep it enabled for a few tests for the UI itself, however.

Author: Andrew Or <andrewor14@gmail.com>

Closes #2363 from andrewor14/disable-ui-for-tests and squashes the following commits:

332a7d5 [Andrew Or] No need to set spark.ui.port to 0 anymore
30c93a2 [Andrew Or] Simplify streaming UISuite
a431b84 [Andrew Or] Fix streaming test failures
8f5ae53 [Andrew Or] Fix no new line at the end
29c9b5b [Andrew Or] Disable SparkUI for tests

1 files changed, 12 insertions, 4 deletions

diff --git a/streaming/src/test/scala/org/apache/spark/streaming/UISuite.scala b/streaming/src/test/scala/org/apache/spark/streaming/UISuite.scala
index 2a0db75649..4c7e43c294 100644
--- a/streaming/src/test/scala/org/apache/spark/streaming/UISuite.scala
+++ b/streaming/src/test/scala/org/apache/spark/streaming/UISuite.scala
@@ -24,13 +24,22 @@ import org.scalatest.FunSuite
 import org.scalatest.concurrent.Eventually._
 import org.scalatest.time.SpanSugar._
 
+import org.apache.spark.SparkConf
+
 class UISuite extends FunSuite {
 
   // Ignored: See SPARK-1530
   ignore("streaming tab in spark UI") {
-    val ssc = new StreamingContext("local", "test", Seconds(1))
+    val conf = new SparkConf()
+      .setMaster("local")
+      .setAppName("test")
+      .set("spark.ui.enabled", "true")
+    val ssc = new StreamingContext(conf, Seconds(1))
+    assert(ssc.sc.ui.isDefined, "Spark UI is not started!")
+    val ui = ssc.sc.ui.get
+
     eventually(timeout(10 seconds), interval(50 milliseconds)) {
-      val html = Source.fromURL(ssc.sparkContext.ui.appUIAddress).mkString
+      val html = Source.fromURL(ui.appUIAddress).mkString
       assert(!html.contains("random data that should not be present"))
       // test if streaming tab exist
       assert(html.toLowerCase.contains("streaming"))
@@ -39,8 +48,7 @@ class UISuite extends FunSuite {
     }
 
     eventually(timeout(10 seconds), interval(50 milliseconds)) {
-      val html = Source.fromURL(
-        ssc.sparkContext.ui.appUIAddress.stripSuffix("/") + "/streaming").mkString
+      val html = Source.fromURL(ui.appUIAddress.stripSuffix("/") + "/streaming").mkString
       assert(html.toLowerCase.contains("batch"))
       assert(html.toLowerCase.contains("network"))
     }