Fix issue when cleaning up crfsuite files (#843)

fix #806

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file.
 ### Fixed
 - Invalidate importlib caches after dynamically installing module [#838](https://github.com/snipsco/snips-nlu/pull/838)
 - Automatically generate documentation for supported languages and builtin entities [#841](https://github.com/snipsco/snips-nlu/pull/841)
+- Fix issue when cleaning up crfsuite files [#843](https://github.com/snipsco/snips-nlu/pull/843)
 
 ## [0.20.0] - 2019-07-16
 ### Added

snips_nlu/slot_filler/crf_slot_filler.py

@@ -394,14 +394,12 @@ def from_path(cls, path, **shared):
             slot_filler.crf_model = crf
         return slot_filler
 
+    def _cleanup(self):
+        if self.crf_model is not None:
+            self.crf_model.modelfile.cleanup()
+
     def __del__(self):
-        if self.crf_model is None or self.crf_model.modelfile.name is None:
-            return
-        try:
-            Path(self.crf_model.modelfile.name).unlink()
-        except OSError as e:
-            logger.warning("Unable to remove CRF model file at path '%s': %s",
-                           self.crf_model.modelfile.name, repr(e))
+        self._cleanup()
 
 
 def _get_crf_model(crf_args):

snips_nlu/tests/test_crf_slot_filler.py

@@ -1014,3 +1014,23 @@ def test_training_should_be_reproducible(self):
                              slot_filler2.crf_model.state_features_)
         self.assertDictEqual(slot_filler1.crf_model.transition_features_,
                              slot_filler2.crf_model.transition_features_)
+
+    def test_should_cleanup(self):
+        # Given
+        dataset_stream = io.StringIO("""
+---
+type: intent
+name: MakeTea
+utterances:
+- make me a [beverage_temperature:Temperature](hot) cup of tea
+- make me [number_of_cups:snips/number](five) tea cups""")
+        dataset = Dataset.from_yaml_files("en", [dataset_stream])
+        slot_filler = CRFSlotFiller().fit(dataset, "MakeTea")
+        crf_file = Path(slot_filler.crf_model.modelfile.name)
+        self.assertTrue(crf_file.exists())
+
+        # When
+        slot_filler._cleanup()  # pylint:disable=protected-access
+
+        # Then
+        self.assertFalse(crf_file.exists())