diff --git a/spark/src/test/scala/org/apache/spark/sql/CometTestBase.scala b/spark/src/test/scala/org/apache/spark/sql/CometTestBase.scala
index f85d5048a..69b96b7b7 100644
--- a/spark/src/test/scala/org/apache/spark/sql/CometTestBase.scala
+++ b/spark/src/test/scala/org/apache/spark/sql/CometTestBase.scala
@@ -69,6 +69,7 @@ abstract class CometTestBase
     conf.set("spark.hadoop.fs.file.impl", classOf[DebugFilesystem].getName)
     conf.set("spark.ui.enabled", "false")
     conf.set(SQLConf.SHUFFLE_PARTITIONS, 10) // reduce parallelism in tests
+    conf.set(CometConf.COMET_ANSI_MODE_ENABLED.key, "true")
     conf.set(SHUFFLE_MANAGER, shuffleManager)
     conf.set(MEMORY_OFFHEAP_ENABLED.key, "true")
     conf.set(MEMORY_OFFHEAP_SIZE.key, "2g")