diff --git a/nixos/tests/loki.nix b/nixos/tests/loki.nix
index bede775b7d3..0c6dff3fdf1 100644
--- a/nixos/tests/loki.nix
+++ b/nixos/tests/loki.nix
@@ -46,7 +46,9 @@ import ./make-test-python.nix ({ lib, pkgs, ... }:
     machine.wait_for_open_port(9080)
     machine.succeed("echo 'Loki Ingestion Test' > /var/log/testlog")
     # should not have access to journal unless specified
-    machine.fail("systemctl show --property=SupplementaryGroups promtail | grep -q systemd-journal")
+    machine.fail(
+        "systemctl show --property=SupplementaryGroups promtail | grep -q systemd-journal"
+    )
     machine.wait_until_succeeds(
         "${pkgs.grafana-loki}/bin/logcli --addr='http://localhost:3100' query --no-labels '{job=\"varlogs\",filename=\"/var/log/testlog\"}' | grep -q 'Loki Ingestion Test'"
     )