diff --git a/flink-table/flink-table-planner/src/test/scala/org/apache/flink/table/planner/runtime/stream/sql/GroupWindowITCase.scala b/flink-table/flink-table-planner/src/test/scala/org/apache/flink/table/planner/runtime/stream/sql/GroupWindowITCase.scala
index 455c02484bdd6..36b2d42ec4a65 100644
--- a/flink-table/flink-table-planner/src/test/scala/org/apache/flink/table/planner/runtime/stream/sql/GroupWindowITCase.scala
+++ b/flink-table/flink-table-planner/src/test/scala/org/apache/flink/table/planner/runtime/stream/sql/GroupWindowITCase.scala
@@ -384,6 +384,7 @@ class GroupWindowITCase(mode: StateBackendMode, useTimestampLtz: Boolean)
 
   @Test
   def testWindowAggregateOnUpsertSource(): Unit = {
+    env.setParallelism(1)
     val upsertSourceDataId = registerData(upsertSourceCurrencyData)
     tEnv.executeSql(
       s"""
@@ -417,7 +418,8 @@ class GroupWindowITCase(mode: StateBackendMode, useTimestampLtz: Boolean)
     val expected = Seq(
       "US Dollar,1,102,1970-01-01T00:00,1970-01-01T00:00:05",
       "Yen,1,1,1970-01-01T00:00,1970-01-01T00:00:05",
-      "Euro,1,118,1970-01-01T00:00:15,1970-01-01T00:00:20")
+      "Euro,1,118,1970-01-01T00:00:15,1970-01-01T00:00:20",
+      "RMB,1,702,1970-01-01T00:00,1970-01-01T00:00:05")
     assertEquals(expected.sorted, sink.getAppendResults.sorted)
   }
 
@@ -472,6 +474,7 @@ class GroupWindowITCase(mode: StateBackendMode, useTimestampLtz: Boolean)
 
   @Test
   def testWindowAggregateOnUpsertSourcePushdownWatermark(): Unit = {
+    env.setParallelism(1)
     val upsertSourceDataId = registerData(upsertSourceCurrencyData)
     tEnv.executeSql(
       s"""
@@ -501,7 +504,7 @@ class GroupWindowITCase(mode: StateBackendMode, useTimestampLtz: Boolean)
     tEnv.sqlQuery(sql).toAppendStream[Row].addSink(sink)
     env.execute()
     val expected = Seq(
-      "1970-01-01T00:00,1970-01-01T00:00:05,102",
+      "1970-01-01T00:00,1970-01-01T00:00:05,702",
       "1970-01-01T00:00:15,1970-01-01T00:00:20,118")
     assertEquals(expected.sorted, sink.getAppendResults.sorted)
   }