diff --git a/tests/lang/eval-fail-hashfile-missing.nix b/tests/lang/eval-fail-hashfile-missing.nix
index 42fb1ec7..ce098b82 100644
--- a/tests/lang/eval-fail-hashfile-missing.nix
+++ b/tests/lang/eval-fail-hashfile-missing.nix
@@ -1,5 +1,5 @@
 let
   paths = [ ./this-file-is-definitely-not-there-7392097 "/and/neither/is/this/37293620" ];
 in
-  builtins.concatLists (map (hash: map (builtins.hashFile hash) paths) ["md5" "sha1" "sha256" "sha512"])
+  toString (builtins.concatLists (map (hash: map (builtins.hashFile hash) paths) ["md5" "sha1" "sha256" "sha512"]))