Raise an error when using unknown intents in intents filter

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## [Unreleased]
+### Fixed
+- Raise an error when using unknown intents in intents filter [#788](https://github.com/snipsco/snips-nlu/pull/788)
+
 ## [0.19.5]
 ### Added
 - Advanced inference logging in the `CRFSlotFiller` [#776](https://github.com/snipsco/snips-nlu/pull/776)

snips_nlu/nlu_engine/nlu_engine.py

@@ -163,6 +163,11 @@ def parse(self, text, intents=None, top_n=None):
         elif isinstance(intents, list):
             intents = set(intents)
 
+        if intents is not None:
+            for intent in intents:
+                if intent not in self.dataset_metadata["slot_name_mappings"]:
+                    raise IntentNotFoundError(intent)
+
         if top_n is None:
             none_proba = 0.0
             for parser in self.intent_parsers:

snips_nlu/tests/test_nlu_engine.py

@@ -271,6 +271,39 @@ class SecondIntentParser(MockIntentParser):
         with self.assertRaises(IntentNotFoundError):
             nlu_engine.get_slots("Hello John", "greeting3")
 
+    def test_parse_should_raise_with_unknown_intent_in_filter(self):
+        # Given
+        dataset_stream = io.StringIO("""
+---
+type: intent
+name: greeting1
+utterances:
+  - Hello [name1](John)
+
+---
+type: intent
+name: goodbye
+utterances:
+  - Goodbye [name](Eric)""")
+        dataset = Dataset.from_yaml_files("en", [dataset_stream]).json
+
+        # pylint:disable=unused-variable
+        @IntentParser.register("my_intent_parser", True)
+        class FirstIntentParser(MockIntentParser):
+            pass
+
+        # pylint:enable=unused-variable
+
+        config = NLUEngineConfig(["my_intent_parser"])
+        nlu_engine = SnipsNLUEngine(config).fit(dataset)
+
+        # When / Then
+        with self.assertRaises(IntentNotFoundError):
+            nlu_engine.parse("Hello John", intents="greeting3")
+
+        with self.assertRaises(IntentNotFoundError):
+            nlu_engine.parse("Hello John", intents=["greeting3"])
+
     def test_should_use_parsers_sequentially(self):
         # Given
         dataset_stream = io.StringIO("""