diff --git a/cms/djangoapps/contentstore/views/tests/test_assets.py b/cms/djangoapps/contentstore/views/tests/test_assets.py
index ea9c6d7a0c..c924b9f1d2 100644
--- a/cms/djangoapps/contentstore/views/tests/test_assets.py
+++ b/cms/djangoapps/contentstore/views/tests/test_assets.py
@@ -59,7 +59,7 @@ class AssetsTestCase(CourseTestCase):
         Returns an in-memory file of the specified type with the given name for testing
         """
         sample_asset = BytesIO()
-        sample_file_contents = "This file is generated by python unit test"
+        sample_file_contents = b"This file is generated by python unit test"
         if asset_type == 'text':
             sample_asset.name = '{name}.txt'.format(name=name)
             sample_asset.write(sample_file_contents)