Handle case of video in a content library with no transcripts.

This partially addresses TNL-1776

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

@@ -14,6 +14,7 @@ from xblock.core import XBlock
 
 from xmodule.exceptions import NotFoundError
 from xmodule.fields import RelativeTime
+from opaque_keys.edx.locator import CourseLocator
 
 from .transcripts_utils import (
     get_or_create_sjson,
@@ -166,6 +167,10 @@ class VideoStudentViewHandlers(object):
         if not self.transcript_language == 'en':
             return response
 
+        # If this video lives in library, the code below is not relevant and will error.
+        if not isinstance(self.course_id, CourseLocator):
+            return response
+
         video_id = request.GET.get('videoId', None)
         if video_id:
             transcript_name = video_id

lms/djangoapps/courseware/tests/test_video_handlers.py

@@ -569,11 +569,7 @@ class TestTranscriptTranslationGetDispatch(TestVideo):
         Set course static_asset_path and ensure we get redirected to that path
         if it isn't found in the contentstore
         """
-        self.course.static_asset_path = 'dummy/static'
-        self.course.save()
-        store = modulestore()
-        with store.branch_setting(ModuleStoreEnum.Branch.draft_preferred, self.course.id):
-            store.update_item(self.course, self.user.id)
+        self._set_static_asset_path()
 
         if attach:
             attach(self.item, sub)
@@ -586,6 +582,27 @@ class TestTranscriptTranslationGetDispatch(TestVideo):
                 response.headerlist
             )
 
+    @patch('xmodule.video_module.VideoModule.course_id', return_value='not_a_course_locator')
+    def test_translation_static_non_course(self, __):
+        """
+        Test that get_static_transcript short-circuits in the case of a non-CourseLocator.
+        This fixes a bug for videos inside of content libraries.
+        """
+        self._set_static_asset_path()
+
+        # When course_id is not mocked out, these values would result in 307, as tested above.
+        request = Request.blank('/translation/en?videoId=12345')
+        response = self.item.transcript(request=request, dispatch='translation/en')
+        self.assertEqual(response.status, '404 Not Found')
+
+    def _set_static_asset_path(self):
+        """ Helper method for setting up the static_asset_path information """
+        self.course.static_asset_path = 'dummy/static'
+        self.course.save()
+        store = modulestore()
+        with store.branch_setting(ModuleStoreEnum.Branch.draft_preferred, self.course.id):
+            store.update_item(self.course, self.user.id)
+
 
 @attr('shard_1')
 class TestStudioTranscriptTranslationGetDispatch(TestVideo):