diff --git a/tests/test_formdata.py b/tests/test_formdata.py
index cceeb22a0..a7370962e 100644
--- a/tests/test_formdata.py
+++ b/tests/test_formdata.py
@@ -477,7 +477,7 @@ def test_backoffice_field_varname(pub):
     assert substvars.get('form_var_backoffice_blah') == 'test'
 
 def test_workflow_data_file_url(pub):
-    upload = Upload('test.txt', 'text/plain', 'ascii')
+    upload = PicklableUpload('test.txt', 'text/plain', 'ascii')
     upload.receive([b'first line', b'second line'])
 
     formdata = formdef.data_class()()