diff --git a/async_asgi_testclient/websocket.py b/async_asgi_testclient/websocket.py
index 4f75024..a05f6a8 100644
--- a/async_asgi_testclient/websocket.py
+++ b/async_asgi_testclient/websocket.py
@@ -131,4 +131,4 @@ async def connect(self):
 
         await self._send({"type": "websocket.connect"})
         msg = await self._receive()
-        assert msg["type"] == "websocket.accept"
+        assert msg["type"] == "websocket.accept", "websocket not accepted, possibly incorrect URL"