added module 'message.py'

chatmastermind/message.py

@@ -0,0 +1,26 @@
+"""
+Module implementing message related functions and classes.
+"""
+from typing import Type, TypeVar
+
+QuestionInst = TypeVar('QuestionInst', bound='Question')
+
+
+class MessageError(Exception):
+    pass
+
+
+class Question(str):
+    """
+    A single question with a defined prefix.
+    """
+    prefix = '=== QUESTION ==='
+
+    def __new__(cls: Type[QuestionInst], string: str) -> QuestionInst:
+        """
+        Make sure the tag string does not contain the default separator.
+        """
+        if cls.prefix in string:
+            raise MessageError(f"Question '{string}' contains the prefix '{cls.prefix}'")
+        instance = super().__new__(cls, string)
+        return instance

chatmastermind/tags.py

@@ -25,7 +25,7 @@ class Tag(str):
         Make sure the tag string does not contain the default separator.
         """
         if cls.default_separator in string:
-            raise TypeError(f"Tag '{string}' contains the separator char '{cls.default_separator}'")
+            raise TagError(f"Tag '{string}' contains the separator char '{cls.default_separator}'")
         instance = super().__new__(cls, string)
         return instance
 

tests/test_main.py

@@ -240,7 +240,7 @@ class TestTag(CmmTestCase):
         self.assertEqual(tag, 'mytag')
 
     def test_invalid_tag(self) -> None:
-        with self.assertRaises(TypeError):
+        with self.assertRaises(TagError):
             Tag('tag with space')
 
     def test_default_separator(self) -> None: