diff --git a/pkgs/pkgs-lib/tests/formats.nix b/pkgs/pkgs-lib/tests/formats.nix
index 14cc85eff31d..2bc4e407fe75 100644
--- a/pkgs/pkgs-lib/tests/formats.nix
+++ b/pkgs/pkgs-lib/tests/formats.nix
@@ -77,8 +77,8 @@ in runBuildTests {
       'false': false
       float: 3.141
       list:
-        - null
-        - null
+      - null
+      - null
       'null': null
       path: ${./formats.nix}
       str: foo