diff --git a/tests/arima/mod1c.mod b/tests/arima/mod1c.mod
index a77478a85..a1a48f3ab 100644
--- a/tests/arima/mod1c.mod
+++ b/tests/arima/mod1c.mod
@@ -23,5 +23,5 @@ stderr y,INV_GAMMA_PDF,0.01,inf;
 end;
 
 varobs x y;
-options_.unit_root_vars = {'x'; 'y'};
+unit_root_vars x y;
 estimation(datafile=data1,nobs=1000,mh_replic=2000,lik_init=2);
\ No newline at end of file