disable some flaky tests

Author: cloud-fan

core/src/test/scala/org/apache/spark/deploy/history/HistoryServerSuite.scala

@@ -314,7 +314,8 @@ class HistoryServerSuite extends SparkFunSuite with BeforeAndAfter with Matchers
     all (directSiteRelativeLinks) should not startWith (knoxBaseUrl)
   }
 
-  test("static relative links are prefixed with uiRoot (spark.ui.proxyBase)") {
+  // TODO (SPARK-31723): re-enable it
+  ignore("static relative links are prefixed with uiRoot (spark.ui.proxyBase)") {
     val uiRoot = Option(System.getenv("APPLICATION_WEB_PROXY_BASE")).getOrElse("/testwebproxybase")
     val page = new HistoryPage(server)
     val request = mock[HttpServletRequest]

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/KafkaRelationSuite.scala

@@ -179,7 +179,8 @@ abstract class KafkaRelationSuiteBase extends QueryTest with SharedSparkSession
       ("3", Seq(("e", "f".getBytes(UTF_8)), ("e", "g".getBytes(UTF_8))))).toDF)
   }
 
-  test("timestamp provided for starting and ending") {
+  // TODO (SPARK-31722): re-enable it
+  ignore("timestamp provided for starting and ending") {
     val (topic, timestamps) = prepareTimestampRelatedUnitTest
 
     // timestamp both presented: starting "first" ending "finalized"

external/kafka-0-10/src/test/scala/org/apache/spark/streaming/kafka010/DirectKafkaStreamSuite.scala

@@ -332,7 +332,8 @@ class DirectKafkaStreamSuite
   }
 
   // Test to verify the offset ranges can be recovered from the checkpoints
-  test("offset recovery") {
+  // TODO (SPARK-31722): re-enable it
+  ignore("offset recovery") {
     val topic = "recovery"
     kafkaTestUtils.createTopic(topic)
     testDir = Utils.createTempDir()
@@ -418,8 +419,9 @@ class DirectKafkaStreamSuite
     ssc.stop()
   }
 
-    // Test to verify the offsets can be recovered from Kafka
-  test("offset recovery from kafka") {
+  // Test to verify the offsets can be recovered from Kafka
+  // TODO (SPARK-31722): re-enable it
+  ignore("offset recovery from kafka") {
     val topic = "recoveryfromkafka"
     kafkaTestUtils.createTopic(topic)
 

streaming/src/test/scala/org/apache/spark/streaming/StreamingContextSuite.scala

@@ -293,7 +293,8 @@ class StreamingContextSuite
     }
   }
 
-  test("stop gracefully") {
+  // TODO (SPARK-31722): re-enable it
+  ignore("stop gracefully") {
     val conf = new SparkConf().setMaster(master).setAppName(appName)
     conf.set("spark.dummyTimeConfig", "3600s")
     val sc = new SparkContext(conf)