withSQLConf used and test commented

sql/core/src/test/scala/org/apache/spark/sql/streaming/continuous/ContinuousSuite.scala

@@ -347,27 +347,29 @@ class ContinuousMetaSuite extends ContinuousSuiteBase {
 class ContinuousEpochBacklogSuite extends ContinuousSuiteBase {
   import testImplicits._
 
-  // We need to specify spark.sql.streaming.continuous.epochBacklogQueueSize.
   override protected def createSparkSession = new TestSparkSession(
     new SparkContext(
       "local[1]",
       "continuous-stream-test-sql-context",
-      sparkConf.set("spark.sql.testkey", "true")
-        .set("spark.sql.streaming.continuous.epochBacklogQueueSize", "10")))
+      sparkConf.set("spark.sql.testkey", "true")))
 
+  // This test forces the backlog to overflow by not standing up enough executors for the query
+  // to make progress.
   test("epoch backlog overflow") {
-    val df = spark.readStream
-      .format("rate")
-      .option("numPartitions", "2")
-      .option("rowsPerSecond", "500")
-      .load()
-      .select('value)
-
-    testStream(df, useV2Sink = true)(
-      StartStream(Trigger.Continuous(1)),
-      ExpectFailure[IllegalStateException] { e =>
-        e.getMessage.contains("queue has exceeded it's maximum")
-      }
-    )
+    withSQLConf(("spark.sql.streaming.continuous.epochBacklogQueueSize", "10")) {
+      val df = spark.readStream
+        .format("rate")
+        .option("numPartitions", "2")
+        .option("rowsPerSecond", "500")
+        .load()
+        .select('value)
+
+      testStream(df, useV2Sink = true)(
+        StartStream(Trigger.Continuous(1)),
+        ExpectFailure[IllegalStateException] { e =>
+          e.getMessage.contains("queue has exceeded it's maximum")
+        }
+      )
+    }
   }
 }