Fixed an issue with the None intent when using the parse top_n API

CHANGELOG.md

@@ -10,6 +10,7 @@ All notable changes to this project will be documented in this file.
 ### Fixed
 - Fixed a crash due to missing resources when refitting the `CRFSlotFiller` [#771](https://github.com/snipsco/snips-nlu/pull/771)
 - Fixed issue with egg fragments in download cli [#769](https://github.com/snipsco/snips-nlu/pull/769)
+- Fixed an issue causing the `None` intent to be ignored when using the `parse` API in conjunction with `intents` and `top_n` [#781](https://github.com/snipsco/snips-nlu/pull/781)
 
 ## [0.19.4] - 2019-03-06
 ### Added

snips_nlu/nlu_engine/nlu_engine.py

@@ -178,7 +178,8 @@ def parse(self, text, intents=None, top_n=None):
         intents_results = self.get_intents(text)
         if intents is not None:
             intents_results = [res for res in intents_results
-                               if res[RES_INTENT_NAME] in intents]
+                               if res[RES_INTENT_NAME] is None
+                               or res[RES_INTENT_NAME] in intents]
         intents_results = intents_results[:top_n]
         results = []
         for intent_res in intents_results:

snips_nlu/tests/test_nlu_engine.py

@@ -105,6 +105,8 @@ def get_slots(self, text, intent):
 
         # When
         results = nlu_engine.parse(text, top_n=3)
+        results_with_filter = nlu_engine.parse(
+            text, intents=["intent1", "intent3"], top_n=3)
 
         # Then
         expected_results = [
@@ -123,7 +125,23 @@ def get_slots(self, text, intent):
                 []
             ),
         ]
+        expected_results_with_filter = [
+            extraction_result(
+                intent_classification_result("intent1", 0.5),
+                [custom_slot(
+                    unresolved_slot((0, 3), "foo", "entity1", "slot1"))]
+            ),
+            extraction_result(
+                intent_classification_result(None, 0.15),
+                []
+            ),
+            extraction_result(
+                intent_classification_result("intent3", 0.05),
+                []
+            ),
+        ]
         self.assertListEqual(expected_results, results)
+        self.assertListEqual(expected_results_with_filter, results_with_filter)
 
     def test_should_get_intents(self):
         # Given