2 files changed, 2 insertions, 1 deletions

diff --git a/src/mailman/chains/headers.py b/src/mailman/chains/headers.py
index 7a77f9f9b..5698740d3 100644
--- a/src/mailman/chains/headers.py
+++ b/src/mailman/chains/headers.py
@@ -96,6 +96,7 @@ class HeaderMatchRule:
 
     def check(self, mlist, msg, msgdata):
         """See `IRule`."""
+        # Collect all the headers in all subparts.
         headers = []
         for p in msg.walk():
             headers.extend(p.get_all(self.header, []))
diff --git a/src/mailman/chains/tests/test_headers.py b/src/mailman/chains/tests/test_headers.py
index 6bba6c1b6..7e7219118 100644
--- a/src/mailman/chains/tests/test_headers.py
+++ b/src/mailman/chains/tests/test_headers.py
@@ -198,7 +198,7 @@ This is junk
 """)
         msgdata = {}
         header_matches = IHeaderMatchList(self._mlist)
-        header_matches.append('Content-Type', 'application', 'hold')
+        header_matches.append('Content-Type', 'application/junk', 'hold')
         # This event subscriber records the event that occurs when the message
         # is processed by the owner chain.
         events = []