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+;;; test-custom-text-enclose--region-or-buffer-bounds.el --- Tests for bounds helper -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for cj/--region-or-buffer-bounds, the single source of the
+;; "operate on the active region, else the whole buffer" contract shared by
+;; the *-in-region-or-buffer editing commands.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'custom-text-enclose)
+
+;;; Normal Cases
+
+(ert-deftest test-ctenc-bounds-uses-region-when-active ()
+  "Normal: with an active region, returns its beginning and end."
+  (cl-letf (((symbol-function 'use-region-p) (lambda () t))
+            ((symbol-function 'region-beginning) (lambda () 3))
+            ((symbol-function 'region-end) (lambda () 8)))
+    (should (equal '(3 . 8) (cj/--region-or-buffer-bounds)))))
+
+(ert-deftest test-ctenc-bounds-uses-whole-buffer-when-no-region ()
+  "Normal: with no active region, returns the whole buffer's bounds."
+  (with-temp-buffer
+    (insert "line one\nline two\n")
+    (cl-letf (((symbol-function 'use-region-p) (lambda () nil)))
+      (should (equal (cons (point-min) (point-max))
+                     (cj/--region-or-buffer-bounds))))))
+
+;;; Boundary Cases
+
+(ert-deftest test-ctenc-bounds-empty-buffer-no-region ()
+  "Boundary: an empty buffer with no region yields equal start and end."
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'use-region-p) (lambda () nil)))
+      (let ((b (cj/--region-or-buffer-bounds)))
+        (should (= (car b) (cdr b)))))))
+
+(provide 'test-custom-text-enclose--region-or-buffer-bounds)
+;;; test-custom-text-enclose--region-or-buffer-bounds.el ends here