feat: verify local_timestamp (apache#4331)

Author: YutaLin

docs/source/contributor-guide/spark_expressions_support.md

@@ -241,7 +241,7 @@
 - [ ] from_utc_timestamp
 - [x] hour
 - [x] last_day
-- [ ] localtimestamp
+- [x] localtimestamp
 - [x] make_date
 - [ ] make_dt_interval
 - [ ] make_interval

docs/source/user-guide/latest/expressions.md

@@ -113,6 +113,7 @@ of expressions that be disabled.
 | FromUnixTime     | `from_unixtime`              |
 | Hour             | `hour`                       |
 | LastDay          | `last_day`                   |
+| LocalTimestamp   | `localtimestamp`             |
 | MakeDate         | `make_date`                  |
 | Minute           | `minute`                     |
 | NextDay          | `next_day`                   |

spark/src/test/resources/sql-tests/expressions/datetime/local_timestamp.sql

@@ -0,0 +1,34 @@
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--   http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing,
+-- software distributed under the License is distributed on an
+-- "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+-- KIND, either express or implied.  See the License for the
+-- specific language governing permissions and limitations
+-- under the License.
+
+statement
+CREATE TABLE test_local_timestamp(id int) USING parquet
+
+statement
+INSERT INTO test_local_timestamp VALUES (1), (2), (3), (4), (NULL)
+
+query
+SELECT localtimestamp() IS NOT NULL
+
+query
+SELECT id, localtimestamp() IS NOT NULL FROM test_local_timestamp
+
+query
+SELECT id FROM test_local_timestamp WHERE localtimestamp() = localtimestamp()
+
+query
+SELECT year(localtimestamp()) = year(current_date())