Adjust help description to accomodate overriding

Author: martinjm97

tap/tap.py

@@ -95,6 +95,9 @@ def __init__(self,
         # Get annotations from self and all super classes up through tap
         self._annotations = self._get_annotations()
 
+        # Set the default description to be the docstring
+        kwargs.setdefault('description', self.__doc__)
+
         # Initialize the super class, i.e. ArgumentParser
         super(Tap, self).__init__(*args, **kwargs)
 
@@ -110,8 +113,6 @@ def __init__(self,
         # Indicate that initialization is complete
         self._initialized = True
 
-        self.description = self.__doc__ or ''
-
     def _add_argument(self, *name_or_flags, **kwargs) -> None:
         """Adds an argument to self (i.e. the super class ArgumentParser).
 

tests/test_integration.py

@@ -1590,5 +1590,36 @@ def configure(self):
         self.assertIn('<Sub Parser>', help_desc)
         self.assertIn('<Root Parser>', help_desc)
 
+    def test_empty_docstring_should_be_empty(self):
+        class NoDesc(Tap):
+            field: str = 'a'
+
+        root_parser = NoDesc()
+        help_info = root_parser.format_help()
+        help_flag = '[-h]'
+        desc_start = help_info.index(help_flag) + len(help_flag)
+        desc_end = help_info.index('options:')
+        desc = help_info[desc_start: desc_end].strip()
+        self.assertEqual(desc, '')
+
+    def test_manual_description_still_works(self):
+        class NoDesc(Tap):
+            field: str = 'a'
+
+        expected_help_desc = 'I exist'
+        help_desc = NoDesc(description=expected_help_desc).format_help()
+        self.assertIn(expected_help_desc, help_desc)
+
+    def test_manual_description_overwrites_docstring(self):
+        class Desc(Tap):
+            """I do not exist"""
+            field: str = 'a'
+
+        expected_help_desc = 'I exist'
+        help_desc = Desc(description=expected_help_desc).format_help()
+        self.assertIn(expected_help_desc, help_desc)
+        self.assertNotIn("I do not exist", help_desc)
+
+
 if __name__ == '__main__':
     unittest.main()