diff --git a/nixos/tests/prometheus-exporters.nix b/nixos/tests/prometheus-exporters.nix
index adc2b467be5..bb87f1a3df9 100644
--- a/nixos/tests/prometheus-exporters.nix
+++ b/nixos/tests/prometheus-exporters.nix
@@ -348,9 +348,13 @@ let
         enable = true;
         url = "http://localhost";
         configFile = pkgs.writeText "json-exporter-conf.json" (builtins.toJSON {
-          metrics = [
-            { name = "json_test_metric"; path = "{ .test }"; }
-          ];
+          modules = {
+            default = {
+              metrics = [
+                { name = "json_test_metric"; path = "{ .test }"; }
+              ];
+            };
+          };
         });
       };
       metricProvider = {