Changes in checking empty intent mapping & new test

- Replaced try/except statement with if/else when checking for empty intent mapping.
- Minor rewording on the exception message.
- Added a new test to check if the exception is correctly raised.

rasa/shared/core/domain.py

@@ -327,9 +327,9 @@ def _transform_intent_properties_for_internal_use(
         """
         name, properties = list(intent.items())[0]
 
-        try:
+        if properties:
             properties.setdefault(USE_ENTITIES_KEY, True)
-        except:
+        else:
             raise InvalidDomain(
                 f"In the `domain.yml` file, the intent `{name}` cannot have value of"
                 f" `{type(properties)}`. This can happen if you add an intent with the"

tests/shared/core/test_domain.py

@@ -1309,10 +1309,10 @@ def test_is_valid_domain_doesnt_raise_with_invalid_yaml(tmpdir: Path):
 
 
 def test_domain_with_empty_intent_mapping():
-    # domain.yml with intent (intent_name) that has a `:` and nothing after it.
-    test_yaml = f"""
-                intents:
-                    - intent_name:"""
+    # domain.yml with intent (intent_name) that has a `:` character
+    # and nothing after it.
+    test_yaml = """intents:
+    - intent_name:"""
 
     with pytest.raises(InvalidDomain):
         Domain.from_yaml(test_yaml).as_dict()