Bugfix/issue 2563 (#2692)

* Issue-2563 Added fallback to english model
* Added test case for checking config set up
* Added more descriptive log message

mycroft/client/speech/hotword_factory.py

@@ -118,9 +118,16 @@ class PocketsphinxHotWord(HotWordEngine):
         return file_name
 
     def create_config(self, dict_name, config):
+        """If language config doesn't exist then
+        we use default language (english) config as a fallback.
+        """
         model_file = join(RECOGNIZER_DIR, 'model', self.lang, 'hmm')
         if not exists(model_file):
-            LOG.error('PocketSphinx model not found at ' + str(model_file))
+            LOG.error(
+                'PocketSphinx model not found at "{}". '.format(model_file) +
+                'Falling back to en-us model'
+            )
+            model_file = join(RECOGNIZER_DIR, 'model', 'en-us', 'hmm')
         config.set_string('-hmm', model_file)
         config.set_string('-dict', dict_name)
         config.set_string('-keyphrase', self.key_phrase)

test/unittests/client/test_local_recognizer.py

@@ -48,6 +48,27 @@ class PocketSphinxRecognizerTest(unittest.TestCase):
         with source as audio:
             assert self.recognizer.found_wake_word(audio.stream.read())
 
+    @patch.object(Configuration, 'get')
+    def testRecognitionFallback(self, mock_config_get):
+        """If language config doesn't exist set default (english)"""
+        conf = base_config()
+        conf['hotwords']['hey mycroft'] = {
+            'lang': 'DOES NOT EXIST',
+            'module': 'pocketsphinx',
+            'phonemes': 'HH EY . M AY K R AO F T',
+            'threshold': 1e-90
+        }
+        conf['lang'] = 'DOES NOT EXIST'
+        mock_config_get.return_value = conf
+
+        rl = RecognizerLoop()
+        ps_hotword = RecognizerLoop.create_wake_word_recognizer(rl)
+
+        expected = 'en-us'
+        res = ps_hotword.decoder.get_config().get_string('-hmm')
+        self.assertEqual(expected, res.split('/')[-2])
+        self.assertEqual('does not exist', ps_hotword.lang)
+
 
 class LocalRecognizerInitTest(unittest.TestCase):
     @patch.object(Configuration, 'get')