test(system-defaults): cover custom-file, backups, and GC-hook registration

system-defaults.el had no coverage for its settings, only its functions (in test-system-defaults-functions.el) and the vc-follow-symlinks default. I added three settings smoke tests: custom-file is redirected to a temp trashbin rather than the repo, backups land under user-emacs-directory/backups, and the minibuffer GC hooks are actually wired onto the minibuffer hooks.

I pulled the sandbox loader the vc-follow-symlinks test had inline into tests/testutil-system-defaults.el so both files share one copy. The backups test clears cj/backup-directory before loading — it's a defvar, so once an earlier test loads the module it keeps that first sandbox path and won't recompute, which made the assertion fail until I forced the recompute.

1 files changed, 68 insertions, 0 deletions

diff --git a/tests/test-system-defaults.el b/tests/test-system-defaults.el
new file mode 100644
index 00000000..bc3694db
--- /dev/null
+++ b/tests/test-system-defaults.el
@@ -0,0 +1,68 @@
+;;; test-system-defaults.el --- Smoke tests for system-defaults settings -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;; system-defaults.el holds high-impact defaults with no behavior of its own
+;; to unit-test, so these are characterization smoke tests on the *settings*
+;; most likely to cause damage if they regressed silently: where Customize
+;; writes land, where backups go, and whether the minibuffer GC hooks are
+;; installed.  Load happens in the shared sandbox (testutil-system-defaults.el).
+;;
+;; The module's functions (cj/disabled, the GC hook bodies, unpropertize-kill-ring,
+;; cj/log-comp-warning) are covered by test-system-defaults-functions.el, and the
+;; vc-follow-symlinks default by test-system-defaults-vc-follow-symlinks.el.
+
+;;; Code:
+
+(require 'ert)
+(add-to-list 'load-path (expand-file-name "tests" user-emacs-directory))
+(require 'testutil-system-defaults)
+
+;;; custom-file redirection
+
+(ert-deftest test-system-defaults-custom-file-redirected-to-tempfile ()
+  "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))
+      (test-system-defaults--load)
+      (should (stringp custom-file))
+      (should (string-prefix-p (file-name-as-directory
+                                (expand-file-name temporary-file-directory))
+                               (expand-file-name custom-file)))
+      (should (string-match-p "emacs-customizations-trashbin-"
+                              (file-name-nondirectory custom-file)))
+      (should-not (string-prefix-p (expand-file-name user-emacs-directory)
+                                   (expand-file-name custom-file))))))
+
+;;; backup directory
+
+(ert-deftest test-system-defaults-backups-redirected-under-user-emacs-dir ()
+  "Normal: backups are redirected into user-emacs-directory/backups.
+cj/backup-directory is a defvar that only recomputes when unbound, so the
+test clears it first to capture the path derived from the sandbox."
+  (test-system-defaults--with-load-environment
+    (makunbound 'cj/backup-directory)
+    (let ((backup-directory-alist nil))
+      (test-system-defaults--load)
+      (let ((dir (cdr (assoc "." backup-directory-alist))))
+        (should dir)
+        (should (string-prefix-p (expand-file-name user-emacs-directory)
+                                 (expand-file-name dir)))
+        (should (string-suffix-p "backups" (directory-file-name dir)))))))
+
+;;; minibuffer GC hooks
+
+(ert-deftest test-system-defaults-minibuffer-gc-hooks-registered ()
+  "Normal: the minibuffer GC raise/restore hooks are installed.
+Their bodies are tested in test-system-defaults-functions.el; this asserts
+they are actually wired onto the minibuffer hooks."
+  (test-system-defaults--with-load-environment
+    (let ((minibuffer-setup-hook nil)
+          (minibuffer-exit-hook nil))
+      (test-system-defaults--load)
+      (should (memq 'cj/minibuffer-setup-hook minibuffer-setup-hook))
+      (should (memq 'cj/minibuffer-exit-hook minibuffer-exit-hook)))))
+
+(provide 'test-system-defaults)
+;;; test-system-defaults.el ends here