Refactor comments and test code

Signed-off-by: Chen Dai <[email protected]>

flint-spark-integration/src/main/scala/org/opensearch/flint/spark/sql/index/FlintSparkIndexAstBuilder.scala

@@ -28,14 +28,7 @@ trait FlintSparkIndexAstBuilder extends FlintSparkSqlExtensionsVisitor[AnyRef] {
 
   /**
    * Represents the basic output schema for the FlintSparkSqlCommand. This schema includes
-   * essential information about each index, such as:
-   *   - Index Name (`flint_index_name`)
-   *   - Index Kind (`kind`)
-   *   - Associated Database (`database`)
-   *   - Table the index is associated with (`table`), which can be nullable
-   *   - Specific Index Name (`index_name`), which can be nullable
-   *   - Auto-refresh status (`auto_refresh`)
-   *   - Current status of the index (`status`)
+   * essential information about each index.
    */
   private val baseOutputSchema = Seq(
     AttributeReference("flint_index_name", StringType, nullable = false)(),
@@ -48,9 +41,7 @@ trait FlintSparkIndexAstBuilder extends FlintSparkSqlExtensionsVisitor[AnyRef] {
 
   /**
    * Extends the base output schema with additional information. This schema is used when the
-   * EXTENDED keyword is present which includes:
-   *   - Error information (`error`), detailing any errors associated with the index, which can be
-   *     nullable.
+   * EXTENDED keyword is present.
    */
   private val extendedOutputSchema = Seq(
     AttributeReference("error", StringType, nullable = true)())

integ-test/src/test/scala/org/opensearch/flint/spark/FlintSparkIndexSqlITSuite.scala

@@ -126,6 +126,14 @@ class FlintSparkIndexSqlITSuite extends FlintSparkSuite with Matchers {
     val activeJob = spark.streams.active.find(_.name == testSkippingFlintIndex)
     awaitStreamingComplete(activeJob.get.id.toString)
 
+    // Assert output contains empty error message
+    def outputError: String = {
+      val df = sql("SHOW FLINT INDEX EXTENDED IN spark_catalog")
+      df.columns should contain("error")
+      df.collect().head.getAs[String]("error")
+    }
+    outputError shouldBe empty
+
     // Trigger next micro batch after 5 seconds with index readonly
     Future {
       Thread.sleep(5000)
@@ -139,13 +147,9 @@ class FlintSparkIndexSqlITSuite extends FlintSparkSuite with Matchers {
         s"INSERT INTO $testTableQualifiedName VALUES (TIMESTAMP '2023-10-01 04:00:00', 'F', 25, 'Vancouver')")
     }
 
-    // Await and store exception as expected
+    // Await to store exception and verify if it's as expected
     flint.flintIndexMonitor.awaitMonitor(Some(testSkippingFlintIndex))
-
-    // Assert output contains error message
-    val df = sql("SHOW FLINT INDEX EXTENDED IN spark_catalog")
-    df.columns should contain("error")
-    df.select(col("error")).collect().head.getString(0) should include("OpenSearchException")
+    outputError should include("OpenSearchException")
 
     deleteTestIndex(testSkippingFlintIndex)
   }