diff --git a/backend/internal/bootstrap/runtime_test.go b/backend/internal/bootstrap/runtime_test.go
index 730cda8d8..bbb5f5087 100644
--- a/backend/internal/bootstrap/runtime_test.go
+++ b/backend/internal/bootstrap/runtime_test.go
@@ -196,6 +196,9 @@ func TestRuntimeOpenStartClose(t *testing.T) {
 		t.Fatalf("desktop unknown proxy path status = %d, want %d", unknownProxyResponse.StatusCode, http.StatusNotFound)
 	}
 
+	// 客户端可能多拨了一条从没发过请求的连接放在空闲池里；服务端要等它满 5 秒才算空闲，
+	// 正好撞上 5 秒的关闭时限。先关掉客户端的空闲连接，只检查运行时自己的关闭。
+	http.DefaultClient.CloseIdleConnections()
 	if err := runtime.Close(context.Background()); err != nil {
 		t.Fatal(err)
 	}