[flink]add ltz test

Author: Alibaba-HZY

fluss-flink/fluss-flink-common/src/test/java/org/apache/fluss/flink/source/FlinkTableSourceITCase.java

@@ -1080,7 +1080,18 @@ void testStreamingReadTimestampPartitionTypePushDown() throws Exception {
                 admin, tablePath1, Arrays.asList("2021-01-01-00-00-00_", "2021-01-02-00-00-00_"));
 
         // TODO add test for timestamp_ltz
-
+        // Test query with TIMESTAMP_LTZ literal
+        String plan1 =
+                tEnv.explainSql(
+                        "select * from partitioned_table_timestamp_ltz where c = cast(TIMESTAMP'2021-01-01 08:00:00' as timestamp_ltz(3)) ");
+        CloseableIterator<Row> collect =
+                tEnv.executeSql("select cast(TIMESTAMP'2021-01-01 08:00:00' as timestamp_ltz(3))")
+                        .collect();
+        org.apache.flink.util.CloseableIterator<Row> rowIter1 =
+                tEnv.executeSql(
+                                "select * from partitioned_table_timestamp_ltz where c = cast(TIMESTAMP'2021-01-01 08:00:00' as timestamp_ltz(3))")
+                        .collect();
+        assertResultsIgnoreOrder(rowIter1, expectedRowValues1, true);
     }
 
     @Test