diff --git a/ucl/userbuiltin_test.go b/ucl/userbuiltin_test.go
index 9c631e7..508d1e7 100644
--- a/ucl/userbuiltin_test.go
+++ b/ucl/userbuiltin_test.go
@@ -124,7 +124,7 @@ func TestInst_SetBuiltin(t *testing.T) {
 			want  string
 		}{
 			{descr: "pass via args", expr: `join (add2 "left" "right")`, want: "left:right"},
-			{descr: "pass via vars", expr: `set x (add2 "blue" "green") ; join $x`, want: "blue:green"},
+			{descr: "pass via vars", expr: `$x = (add2 "blue" "green") ; join $x`, want: "blue:green"},
 		}
 
 		for _, tt := range tests {