diff --git a/nixos/tests/pgjwt.nix b/nixos/tests/pgjwt.nix
index 8d3310b74eb3..8100b874b5a6 100644
--- a/nixos/tests/pgjwt.nix
+++ b/nixos/tests/pgjwt.nix
@@ -18,17 +18,15 @@ with pkgs; {
 
   testScript = { nodes, ... }:
   let
-    sqlSU = "${nodes.master.config.services.postgresql.superUser}";
+    sqlSU = "${nodes.master.services.postgresql.superUser}";
     pgProve = "${pkgs.perlPackages.TAPParserSourceHandlerpgTAP}";
+    inherit (nodes.master.services.postgresql.package.pkgs) pgjwt;
   in
   ''
     start_all()
     master.wait_for_unit("postgresql")
     master.succeed(
-        "${pkgs.gnused}/bin/sed -e '12 i CREATE EXTENSION pgcrypto;\\nCREATE EXTENSION pgtap;\\nSET search_path TO tap,public;' ${pgjwt.src}/test.sql > /tmp/test.sql"
-    )
-    master.succeed(
-        "${pkgs.sudo}/bin/sudo -u ${sqlSU} PGOPTIONS=--search_path=tap,public ${pgProve}/bin/pg_prove -d postgres -v -f /tmp/test.sql"
+        "${pkgs.sudo}/bin/sudo -u ${sqlSU} PGOPTIONS=--search_path=tap,public ${pgProve}/bin/pg_prove -d postgres -v -f ${pgjwt.src}/test.sql"
     )
   '';
 })