fix(system-defaults): guard server-start and custom-file against batch

A raw module load under --batch started a server and dropped a throwaway custom-file temp on every run; the suite only passed because a testutil stubbed the server. Guard both with (unless noninteractive ...), the established pattern here. Adds a batch-load test for the custom-file guard.

1 files changed, 13 insertions, 1 deletions

diff --git a/tests/test-system-defaults.el b/tests/test-system-defaults.el
index 3c5e59777..928124f56 100644
--- a/tests/test-system-defaults.el
+++ b/tests/test-system-defaults.el
@@ -24,7 +24,10 @@
   "Normal: custom-file points at a throwaway temp file, never the repo.
 This is what stops accidental Customize writes from landing in tracked init."
   (test-system-defaults--with-load-environment
-    (let ((custom-file nil))
+    ;; noninteractive is t under ERT batch; bind it nil so the interactive
+    ;; redirect runs (the module guards the redirect to interactive sessions).
+    (let ((custom-file nil)
+          (noninteractive nil))
       (test-system-defaults--load)
       (should (stringp custom-file))
       (should (string-prefix-p (file-name-as-directory
@@ -35,6 +38,15 @@ This is what stops accidental Customize writes from landing in tracked init."
       (should-not (string-prefix-p (expand-file-name user-emacs-directory)
                                    (expand-file-name custom-file))))))
 
+(ert-deftest test-system-defaults-custom-file-not-littered-in-batch ()
+  "Boundary: a noninteractive (batch) load does not create a trashbin custom-file.
+Guards make validate-modules / byte-compile from dropping a temp file per run."
+  (test-system-defaults--with-load-environment
+    (let ((custom-file nil)
+          (noninteractive t))
+      (test-system-defaults--load)
+      (should-not custom-file))))
+
 ;;; backup directory
 
 (ert-deftest test-system-defaults-backups-redirected-under-user-emacs-dir ()