diff --git a/test/effect-based/t_fork_join.ml b/test/effect-based/t_fork_join.ml
index 007baa55..a187e8cd 100644
--- a/test/effect-based/t_fork_join.ml
+++ b/test/effect-based/t_fork_join.ml
@@ -209,7 +209,7 @@ module Evaluator = struct
         ( clamp_if_base 3,
           let+ f = gen_fun
           and+ csize = 1 -- 16
-          and+ l = list_size (1 -- 290) (gen 1)
+          and+ l = list_size (0 -- 290) (gen 1)
           and+ r = oneofl [ R_add; R_max; R_add_shift ] in
           Map_arr (csize, f, l, r) );
         ( clamp_if_base 2,