Refactor and test function to retrieve intent names

Since the main problem of bug OSS-413 is that intents with
attributes are not retrieved well the test was implemented to
use domains with and without intent definitions using attributes.

rasa/core/training/interactive.py

@@ -1457,6 +1457,20 @@ def _print_help(skip_visualization: bool) -> None:
     )
 
 
+def intent_names_from_domain(domain: Any) -> List[Text]:
+    """Get a list of the possible intents names from the domain specification.
+
+    This is its own function as intents are non-trivial to unpack and this
+    warrants testing.
+    """
+    domain_intents = domain.get("intents", []) if domain is not None else []
+
+    # intents with properties such as `use_entities` or `ignore_entities`
+    # are a dictionary which needs unpacking. Other intents are strings
+    # and can be used as-is.
+    return [next(iter(i)) if isinstance(i, dict) else i for i in domain_intents]
+
+
 async def record_messages(
     endpoint: EndpointConfig,
     file_importer: TrainingDataImporter,
@@ -1475,17 +1489,7 @@ async def record_messages(
             )
             return
 
-        domain_intents = domain.get("intents", []) if domain is not None else []
-
-        # intents with properties such as `use_entities` or `ignore_entities`
-        # are a dictionary which needs unpacking. Other intents are strings
-        # and can be used as-is.
-        intents = [
-            next(iter(i))
-            if isinstance(i, dict)
-            else i
-            for i in domain_intents
-        ]
+        intents = intent_names_from_domain(domain)
 
         num_messages = 0
 

tests/core/training/test_interactive.py

@@ -54,6 +54,38 @@ def mock_file_importer(
     )
 
 
+@pytest.mark.parametrize(
+    "domain_file, expected_intents",
+    [
+        (
+            "data/test_domains/default_unfeaturized_entities.yml",
+            [
+                "greet",
+                "default",
+                "goodbye",
+                "thank",
+                "ask",
+                "why",
+                "pure_intent",
+            ],
+        ),
+        (
+            "data/test_domains/default.yml",
+            [
+                "greet",
+                "default",
+                "goodbye",
+            ],
+        ),
+    ],
+)
+def test_intent_names_from_domain(domain_file, expected_intents):
+    test_domain = Domain.load(domain_file)
+
+    intents = interactive.intent_names_from_domain(test_domain.as_dict())
+    assert set(intents) == set(expected_intents)
+
+
 async def test_send_message(mock_endpoint: EndpointConfig):
     sender_id = uuid.uuid4().hex