Hash byte strings.

lms/djangoapps/discussion/rest_api/tests/utils.py

@@ -531,7 +531,7 @@ class ProfileImageTestMixin(object):
         Returns the expected user profile data for a given username
         """
         url = 'http://example-storage.com/profile-images/{filename}_{{size}}.jpg?v={timestamp}'.format(
-            filename=hashlib.md5('secret' + username).hexdigest(),
+            filename=hashlib.md5(b'secret' + username.encode('utf-8')).hexdigest(),
             timestamp=self.TEST_PROFILE_IMAGE_UPLOADED_AT.strftime("%s")
         )
         return {