Catch exception if for en no default subs is uploaded.

common/lib/xmodule/xmodule/video_module/video_module.py

@@ -342,7 +342,7 @@ class VideoModule(VideoFields, XModule):
 
             try:
                 transcript = self.translation(request.GET.get('videoId'))
-            except TranscriptException as ex:
+            except (TranscriptException, NotFoundError) as ex:
                 log.info(ex.message)
                 response = Response(status=404)
             else:
@@ -414,6 +414,9 @@ class VideoModule(VideoFields, XModule):
         Filenames naming:
             en: subs_videoid.srt.sjson
             non_en: uk_subs_videoid.srt.sjson
+
+        Raises:
+            NotFoundError if for 'en' subtitles no asset is uploaded.
         """
         if self.transcript_language == 'en':
             return asset(self.location, subs_id).data

lms/djangoapps/courseware/tests/test_video_handlers.py

@@ -161,6 +161,8 @@ class TestVideoTranscriptTranslation(TestVideo):
         self.item_descriptor.render('student_view')
         self.item = self.item_descriptor.xmodule_runtime.xmodule_instance
 
+    # Tests for `download` dispatch:
+
     def test_language_is_not_supported(self):
         request = Request.blank('/download?language=ru')
         response = self.item.transcript(request=request, dispatch='download')
@@ -177,6 +179,15 @@ class TestVideoTranscriptTranslation(TestVideo):
         response = self.item.transcript(request=request, dispatch='download')
         self.assertEqual(response.body, 'Subs!')
 
+    def test_download_en_no_sub(self):
+        request = Request.blank('/download?language=en')
+        response = self.item.transcript(request=request, dispatch='download')
+        self.assertEqual(response.status, '404 Not Found')
+        with self.assertRaises(NotFoundError):
+            self.item.get_transcript()
+
+    # Tests for `translation` dispatch:
+
     def test_translation_fails(self):
         # No videoId
         request = Request.blank('/translation?language=ru')