test(config-utilities): cover with-timer, compile-buffer, summary, info commands

Four new test files extending the existing coverage of
cj/emacs-build--format-build-time. The interactive heavyweights
(cj/recompile-emacs-home, cj/delete-emacs-home-compiled-files,
cj/benchmark-this-method, cj/validate-org-agenda-timestamps) are out
of scope for this pass — each needs an internal/wrapper split first
before tests can exercise the logic without UI.

- with-timer macro: 4 tests asserting it returns the FORMS' value,
  evaluates the body exactly once, emits both announce and done
  messages, and returns the last form when given multiple.
- cj/compile-this-elisp-buffer: 6 tests dispatching across native-async,
  native-sync, and byte-compile fallbacks, plus the not-elisp /
  no-buffer-file-name error paths and the sync-native error catch.
- cj/emacs-build--summary-string: 5 tests asserting the shape of the
  multi-line report (Version, System, Build date, Capabilities section,
  yes/no flag rendering) without locking exact wording.
- info-commands smoke: 5 tests exercising cj/info-emacs-build,
  cj/info-loaded-packages, cj/info-loaded-features, cj/reload-init-file,
  and cj/org-alert-list-timers via boundary-mocked pop-to-buffer and
  load-file, asserting buffer creation, content shape, or echo-area
  message as appropriate.

20 new tests, all passing. Full suite green.

1 files changed, 95 insertions, 0 deletions

diff --git a/tests/test-config-utilities--compile-this-elisp-buffer.el b/tests/test-config-utilities--compile-this-elisp-buffer.el
new file mode 100644
index 00000000..fb5e288a
--- /dev/null
+++ b/tests/test-config-utilities--compile-this-elisp-buffer.el
@@ -0,0 +1,95 @@
+;;; test-config-utilities--compile-this-elisp-buffer.el --- Tests for cj/compile-this-elisp-buffer -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for `cj/compile-this-elisp-buffer'. The function dispatches
+;; among native-compile-async, native-compile (sync), and
+;; byte-compile-file based on which is fboundp. Tests force each
+;; branch by mocking fboundp at the boundary.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'config-utilities)
+
+(defmacro test-config-utilities--with-elisp-buffer (path &rest body)
+  "Run BODY in a temp buffer visiting PATH (a .el file path).
+Skips the interactive `save-buffer' so tests stay free of disk side
+effects."
+  (declare (indent 1) (debug t))
+  `(with-temp-buffer
+     (setq buffer-file-name ,path)
+     (cl-letf (((symbol-function 'save-buffer) (lambda () nil)))
+       ,@body)))
+
+(ert-deftest test-config-utilities-compile-buffer-not-elisp-raises ()
+  "Error: a buffer whose file isn't .el raises `user-error'."
+  (test-config-utilities--with-elisp-buffer "/tmp/not-elisp.txt"
+    (should-error (cj/compile-this-elisp-buffer) :type 'user-error)))
+
+(ert-deftest test-config-utilities-compile-buffer-no-buffer-file-name-raises ()
+  "Error: a buffer with no `buffer-file-name' raises `user-error'."
+  (with-temp-buffer
+    (setq buffer-file-name nil)
+    (should-error (cj/compile-this-elisp-buffer) :type 'user-error)))
+
+(ert-deftest test-config-utilities-compile-buffer-prefers-native-async ()
+  "Normal: `native-compile-async' is preferred when available."
+  (let (called-with)
+    (test-config-utilities--with-elisp-buffer "/tmp/some.el"
+      (cl-letf (((symbol-function 'fboundp)
+                 (lambda (sym)
+                   (memq sym '(native-compile-async native-compile byte-compile-file))))
+                ((symbol-function 'native-compile-async)
+                 (lambda (file) (setq called-with file)))
+                ((symbol-function 'native-compile)
+                 (lambda (_) (error "should not call sync native-compile")))
+                ((symbol-function 'byte-compile-file)
+                 (lambda (_) (error "should not call byte-compile-file"))))
+        (cj/compile-this-elisp-buffer)
+        (should (equal called-with "/tmp/some.el"))))))
+
+(ert-deftest test-config-utilities-compile-buffer-falls-back-to-sync-native ()
+  "Normal: `native-compile' is used when async isn't available."
+  (let (called-with)
+    (test-config-utilities--with-elisp-buffer "/tmp/some.el"
+      (cl-letf (((symbol-function 'fboundp)
+                 (lambda (sym) (memq sym '(native-compile byte-compile-file))))
+                ((symbol-function 'native-compile)
+                 (lambda (file) (setq called-with file)))
+                ((symbol-function 'byte-compile-file)
+                 (lambda (_) (error "should not call byte-compile-file"))))
+        (cj/compile-this-elisp-buffer)
+        (should (equal called-with "/tmp/some.el"))))))
+
+(ert-deftest test-config-utilities-compile-buffer-falls-back-to-byte-compile ()
+  "Normal: `byte-compile-file' is used when neither native option is available."
+  (let (called-with)
+    (test-config-utilities--with-elisp-buffer "/tmp/some.el"
+      (cl-letf (((symbol-function 'fboundp)
+                 (lambda (sym) (eq sym 'byte-compile-file)))
+                ((symbol-function 'byte-compile-file)
+                 (lambda (file) (setq called-with file) "/tmp/some.elc")))
+        (cj/compile-this-elisp-buffer)
+        (should (equal called-with "/tmp/some.el"))))))
+
+(ert-deftest test-config-utilities-compile-buffer-handles-sync-native-error ()
+  "Error: a sync `native-compile' that signals is caught and reported.
+Asserts no error escapes by running the function and checking that the
+message captured contains the failure prefix."
+  (test-config-utilities--with-elisp-buffer "/tmp/some.el"
+    (let (captured)
+      (cl-letf (((symbol-function 'fboundp)
+                 (lambda (sym) (memq sym '(native-compile byte-compile-file))))
+                ((symbol-function 'native-compile)
+                 (lambda (_) (error "boom")))
+                ((symbol-function 'message)
+                 (lambda (fmt &rest args)
+                   (setq captured (apply #'format fmt args)))))
+        (cj/compile-this-elisp-buffer))
+      (should (string-match-p "Native compile failed" captured)))))
+
+(provide 'test-config-utilities--compile-this-elisp-buffer)
+;;; test-config-utilities--compile-this-elisp-buffer.el ends here