enhance tests

Author: rafafrdz

spark/src/test/scala/org/apache/comet/CometTemporalExpressionSuite.scala

@@ -116,13 +116,13 @@ class CometTemporalExpressionSuite extends CometTestBase with AdaptiveSparkPlanH
 
   test("to_date parses date literal") {
     withoutConstantFolding {
-      checkSparkAnswer("SELECT to_date('2026-01-30')")
+      checkSparkAnswerAndOperator("SELECT to_date('2026-01-30')")
     }
   }
 
   test("to_date parses date literal with explicit format") {
     withoutConstantFolding {
-      checkSparkAnswer("SELECT to_date('2026/01/30', 'yyyy/MM/dd')")
+      checkSparkAnswerAndOperator("SELECT to_date('2026/01/30', 'yyyy/MM/dd')")
     }
   }
 
@@ -136,7 +136,7 @@ class CometTemporalExpressionSuite extends CometTestBase with AdaptiveSparkPlanH
         .createDataFrame(spark.sparkContext.parallelize(data), schema)
         .createOrReplaceTempView("string_tbl")
 
-      checkSparkAnswer("SELECT dt_str, to_date(dt_str) FROM string_tbl")
+      checkSparkAnswerAndOperator("SELECT dt_str, to_date(dt_str) FROM string_tbl")
     }
   }
 
@@ -151,14 +151,15 @@ class CometTemporalExpressionSuite extends CometTestBase with AdaptiveSparkPlanH
           .createDataFrame(spark.sparkContext.parallelize(data), schema)
           .createOrReplaceTempView("string_tbl")
 
-        checkSparkAnswer("SELECT dt_str, to_date(dt_str, 'yyyy/MM/dd') FROM string_tbl")
+        checkSparkAnswerAndOperator(
+          "SELECT dt_str, to_date(dt_str, 'yyyy/MM/dd') FROM string_tbl")
       }
     }
   }
 
   test("to_date parses timestamp literal string") {
     withoutConstantFolding {
-      checkSparkAnswer("SELECT to_date('2026-01-30 04:17:52')")
+      checkSparkAnswerAndOperator("SELECT to_date('2026-01-30 04:17:52')")
     }
   }
 
@@ -176,7 +177,49 @@ class CometTemporalExpressionSuite extends CometTestBase with AdaptiveSparkPlanH
         .createDataFrame(spark.sparkContext.parallelize(data), schema)
         .createOrReplaceTempView("string_tbl")
 
-      checkSparkAnswer("SELECT dt_str, to_date(dt_str) FROM string_tbl")
+      checkSparkAnswerAndOperator("SELECT dt_str, to_date(dt_str) FROM string_tbl")
+    }
+  }
+
+  test("to_date returns null for malformed input when ANSI is disabled") {
+    withSQLConf(SQLConf.ANSI_ENABLED.key -> "false") {
+      withTempView("string_tbl") {
+        val schema = StructType(Seq(StructField("dt_str", DataTypes.StringType, nullable = true)))
+
+        val data = Seq(Row("2026-01-30"), Row("malformed"), Row(null))
+
+        spark
+          .createDataFrame(spark.sparkContext.parallelize(data), schema)
+          .createOrReplaceTempView("string_tbl")
+
+        checkSparkAnswerAndOperator("SELECT dt_str, to_date(dt_str) FROM string_tbl")
+      }
+    }
+  }
+
+  test("to_date throws for malformed input when ANSI is enabled") {
+    withSQLConf(SQLConf.ANSI_ENABLED.key -> "true") {
+      withTempView("string_tbl") {
+        val schema = StructType(Seq(StructField("dt_str", DataTypes.StringType, nullable = true)))
+
+        val data = Seq(Row("2026-01-30"), Row("malformed"), Row(null))
+
+        spark
+          .createDataFrame(spark.sparkContext.parallelize(data), schema)
+          .createOrReplaceTempView("string_tbl")
+
+        checkSparkAnswerMaybeThrows(sql("SELECT dt_str, to_date(dt_str) FROM string_tbl")) match {
+          case (Some(sparkExc), Some(cometExc)) =>
+            assert(sparkExc.getMessage.toLowerCase.contains("date"))
+            assert(cometExc.getMessage.toLowerCase.contains("date"))
+          case (Some(_), None) =>
+            fail("Expected Comet to throw when Spark throws")
+          case (None, Some(cometExc)) =>
+            throw cometExc
+          case _ =>
+            fail("Expected both Spark and Comet to throw in ANSI mode")
+        }
+      }
     }
   }