1 files changed, 4 insertions, 1 deletions

diff --git a/src/mailman/tests/test_documentation.py b/src/mailman/tests/test_documentation.py
index 48b71d72c..0409e737c 100644
--- a/src/mailman/tests/test_documentation.py
+++ b/src/mailman/tests/test_documentation.py
@@ -69,16 +69,19 @@ class chdir:
 
 
 
-def specialized_message_from_string(text):
+def specialized_message_from_string(unicode_text):
     """Parse text into a message object.
 
     This is specialized in the sense that an instance of Mailman's own Message
     object is returned, and this message object has an attribute
     `original_size` which is the pre-calculated size in bytes of the message's
     text representation.
+
+    Also, the text must be ASCII-only unicode.
     """
     # This mimic what Switchboard.dequeue() does when parsing a message from
     # text into a Message instance.
+    text = unicode_text.encode('ascii')
     original_size = len(text)
     message = message_from_string(text, Message)
     message.original_size = original_size