Tests coverage

aiogram/utils/text_decorations.py

@@ -74,6 +74,8 @@ class TextDecoration(ABC):
         if entity.type == MessageEntityType.CUSTOM_EMOJI:
             return self.custom_emoji(value=text, custom_emoji_id=cast(str, entity.custom_emoji_id))
 
+        # This case is not possible because of `if` above, but if any new entity is added to
+        # API it will be here too
         return self.quote(text)
 
     def unparse(self, text: str, entities: Optional[List[MessageEntity]] = None) -> str:

tests/test_utils/test_text_decorations.py

@@ -113,6 +113,14 @@ class TestTextDecoration:
     ):
         assert decorator.apply_entity(entity, "test") == result
 
+    def test_unknown_apply_entity(self):
+        assert (
+            html_decoration.apply_entity(
+                MessageEntity(type="unknown", offset=0, length=5), "<test>"
+            )
+            == "&lt;test&gt;"
+        )
+
     @pytest.mark.parametrize(
         "decorator,before,after",
         [