3 files changed, 6 insertions, 4 deletions

diff --git a/src/mailman/rest/testing/server.py b/src/mailman/rest/testing/server.py
index 35a3f2b72..c4fe2f1ec 100644
--- a/src/mailman/rest/testing/server.py
+++ b/src/mailman/rest/testing/server.py
@@ -44,6 +44,7 @@ class TestableServer:
         self.server = make_server()
         self.event = threading.Event()
         self.thread = threading.Thread(target=self.loop)
+        self.thread.daemon = True
         
     def start(self):
         """Start the server."""
diff --git a/src/mailman/rest/urls.py b/src/mailman/rest/urls.py
index 5d8d7930b..cdd921d4e 100644
--- a/src/mailman/rest/urls.py
+++ b/src/mailman/rest/urls.py
@@ -69,8 +69,7 @@ class AbsoluteURLMapper:
         # Special cases.
         if isinstance(ob, AdminWebServiceApplication):
             return ''
-        urls = dict(
-            system='system',
-            domains='domains',
-            )
+        urls = {
+            system: 'system',
+            }
         return urls[ob]
diff --git a/src/mailman/testing/helpers.py b/src/mailman/testing/helpers.py
index 0f7d2ed25..7c225d788 100644
--- a/src/mailman/testing/helpers.py
+++ b/src/mailman/testing/helpers.py
@@ -137,6 +137,7 @@ class TestableMaster(Master):
         self.start_check = start_check
         self.event = threading.Event()
         self.thread = threading.Thread(target=self.loop)
+        self.thread.daemon = True
         self._started_kids = None
 
     def start(self, *qrunners):
@@ -194,6 +195,7 @@ class SMTPServer:
         self.port = int(config.mta.smtp_port)
         self._server = Server((self.host, self.port), self._queue)
         self._thread = threading.Thread(target=self._server.start)
+        self._thread.daemon = True
 
     def start(self):
         """Start the smtp server in a thread."""