diff --git a/src/wormhole_transit_relay/test/test_service.py b/src/wormhole_transit_relay/test/test_service.py
index 23faed8..9ab30c8 100644
--- a/src/wormhole_transit_relay/test/test_service.py
+++ b/src/wormhole_transit_relay/test/test_service.py
@@ -50,3 +50,21 @@ class Service(unittest.TestCase):
                 for s in services.services
             )
         )
+
+    def test_websocket_explicit_url(self):
+        """
+        A websocket factory is created with --websocket and
+        --websocket-url
+        """
+        o = server_tap.Options()
+        o.parseOptions([
+            "--websocket=tcp:4004",
+            "--websocket-url=ws://example.com:4004",
+        ])
+        services = server_tap.makeService(o)
+        self.assertTrue(
+            any(
+                isinstance(s.factory, WebSocketServerFactory)
+                for s in services.services
+            )
+        )