add unit test for parser

Author: wj-Mcat

tests/test_integration.py

@@ -3,6 +3,7 @@
 import os
 from pathlib import Path
 import pickle
+from re import L
 import sys
 from tempfile import TemporaryDirectory
 from typing import Any, Iterable, List, Optional, Set, Tuple, Union
@@ -1561,5 +1562,33 @@ def test_pickle(self):
         self.assertEqual(loaded_args.as_dict(), args.as_dict())
 
 
+class TestParserDescription(TestCase):
+    def test_root_parser_description(self):
+        class RootParser(Tap):
+            """<Root Parser>"""
+            field: str = '1'
+        
+        root_parser = RootParser()
+        help_info = root_parser.format_help()
+        self.assertIn('<Root Parser>', help_info)
+
+    def test_sub_parser_description(self):
+
+        class SubParser(Tap):
+            """<Sub Parser>"""
+            sub_field: str = '2'
+        
+        class RootParser(Tap):
+            """<Root Parser>"""
+            field: str = '1'
+
+            def configure(self):
+                self.add_subparsers(help='All sub parser')
+                self.add_subparser('sub', SubParser)
+        
+        help_desc = RootParser().format_help()
+        self.assertIn('<Sub Parser>', help_desc)
+        self.assertIn('<Root Parser>', help_desc)
+
 if __name__ == '__main__':
     unittest.main()