diff --git a/tests/modules/programs/firefox/deprecated-native-messenger.nix b/tests/modules/programs/firefox/deprecated-native-messenger.nix
index 3bcdbe679..63b5a3629 100644
--- a/tests/modules/programs/firefox/deprecated-native-messenger.nix
+++ b/tests/modules/programs/firefox/deprecated-native-messenger.nix
@@ -16,7 +16,7 @@ with lib;
           preferLocalBuild = true;
           allowSubstitutes = false;
         } ''
-          mkdir -p "$out/bin"
+          mkdir -p "$out"/{bin,lib}
           touch "$out/bin/firefox"
           chmod 755 "$out/bin/firefox"
         '';