diff --git a/rust/parity/parity.py b/rust/parity/parity.py
index 4d63b1c..21bde67 100755
--- a/rust/parity/parity.py
+++ b/rust/parity/parity.py
@@ -432,7 +432,10 @@ def log_message(self, *args):
 
         self.server = http.server.ThreadingHTTPServer(("127.0.0.1", 0), Handler)
         self.url = f"http://127.0.0.1:{self.server.server_address[1]}"
-        threading.Thread(target=self.server.serve_forever, daemon=True).start()
+        # Hundreds of cases stop a fixture after its last response. Avoid the
+        # default half-second shutdown poll on every completed case.
+        threading.Thread(target=self.server.serve_forever,
+                         kwargs={"poll_interval": 0.01}, daemon=True).start()
 
     def close(self):
         self.server.shutdown()