Don't double-close a WebSocket in web_socket_test.
diff --git a/test/web_socket_test.dart b/test/web_socket_test.dart
index 60934c5..4da985a 100644
--- a/test/web_socket_test.dart
+++ b/test/web_socket_test.dart
@@ -14,7 +14,7 @@
     return HttpServer.bind("localhost", 0).then((server) {
       server.transform(new WebSocketTransformer()).listen((webSocket) {
         webSocket.add("hello!");
-        webSocket.first.then((request) {
+        webSocket.listen((request) {
           expect(request, equals("ping"));
           webSocket.add("pong");
           webSocket.close();