don't re-raise exception if video image is not found

edxval/api.py

@@ -19,8 +19,7 @@ from edxval.exceptions import (  # pylint: disable=unused-import
     ValInternalError,
     ValVideoNotFoundError,
     ValCannotCreateError,
-    ValCannotUpdateError,
-    ValVideoImageNotFoundError
+    ValCannotUpdateError
 )
 
 logger = logging.getLogger(__name__)  # pylint: disable=C0103
@@ -154,7 +153,7 @@ def get_course_video_image_url(course_id=None, edx_video_id=None, video_image=No
         video_image: VideoImage instance
 
     Returns:
-        course video image url
+        course video image url or None if no image found
     """
     storage = get_video_image_storage()
 
@@ -162,7 +161,7 @@ def get_course_video_image_url(course_id=None, edx_video_id=None, video_image=No
         if video_image is None:
             video_image = CourseVideo.objects.get(course_id=course_id, video__edx_video_id=edx_video_id).video_image
     except ObjectDoesNotExist:
-        raise ValVideoImageNotFoundError
+        return None
 
     return storage.url(video_image.image.name)
 
@@ -179,7 +178,6 @@ def update_video_image(edx_video_id, course_id, image_data, file_name):
 
     Raises:
         Raises ValVideoNotFoundError if the CourseVideo cannot be retrieved.
-        Raises ValVideoImageNotFoundError if the VideoImage cannot be retrieved.
     """
     try:
         course_video = CourseVideo.objects.get(course_id=course_id, video__edx_video_id=edx_video_id)

edxval/exceptions.py

@@ -48,10 +48,3 @@ class ValCannotUpdateError(ValError):
     This error is raised when an object cannot be updated
     """
     pass
-
-
-class ValVideoImageNotFoundError(ValError):
-    """
-    This error is raised when a video image is not found
-    """
-    pass

edxval/tests/test_api.py

@@ -1235,6 +1235,14 @@ class CourseVideoImageTest(TestCase):
         image_url = api.get_course_video_image_url(self.course_id, self.edx_video_id)
         self.assertEqual(self.image_url, image_url)
 
+    def test_get_course_video_image_url_no_image(self):
+        """
+        Verify that `get_course_video_image_url` api function returns None when no image is found.
+        """
+        self.course_video.video_image.delete()
+        image_url = api.get_course_video_image_url(self.course_id, self.edx_video_id)
+        self.assertIsNone(image_url)
+
     def test_get_videos_for_course(self):
         """
         Verify that `get_videos_for_course` api function has correct course_video_image_url.