feat: undead-buffers: Add `cj/make-buffer-undead` function and tests

Introduce a new function `cj/make-buffer-undead` that appends a
buffer name to the `cj/undead-buffer-list`, preventing it from being
killed. This comes along with a suite of tests to check various
scenarios and edge cases for handling undead buffers.

Additionally, add tests for related functions:
`cj/kill-buffer-or-bury-alive`, `cj/kill-buffer-and-window`, and
others to ensure they correctly manage buffers, particularly with
undead-status considerations.

Refactor `undead-buffer-list` naming for consistency and clarity in
the module.

1 files changed, 138 insertions, 0 deletions

diff --git a/tests/test-undead-buffers-kill-buffer-or-bury-alive.el b/tests/test-undead-buffers-kill-buffer-or-bury-alive.el
new file mode 100644
index 00000000..60b776e4
--- /dev/null
+++ b/tests/test-undead-buffers-kill-buffer-or-bury-alive.el
@@ -0,0 +1,138 @@
+;;; test-undead-buffers-kill-buffer-or-bury-alive.el --- Tests for cj/kill-buffer-or-bury-alive -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for the cj/kill-buffer-or-bury-alive function from undead-buffers.el
+
+;;; Code:
+
+(require 'ert)
+(require 'undead-buffers)
+(require 'testutil-general)
+
+;;; Setup and Teardown
+
+(defun test-kill-buffer-or-bury-alive-setup ()
+  "Setup for kill-buffer-or-bury-alive tests."
+  (cj/create-test-base-dir))
+
+(defun test-kill-buffer-or-bury-alive-teardown ()
+  "Teardown for kill-buffer-or-bury-alive tests."
+  (cj/delete-test-base-dir))
+
+;;; Normal Cases
+
+(ert-deftest test-kill-buffer-or-bury-alive-regular-buffer-should-kill ()
+  "Killing a regular buffer not in undead list should kill it."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((buf (generate-new-buffer "*test-regular*")))
+        (should (buffer-live-p buf))
+        (cj/kill-buffer-or-bury-alive buf)
+        (should-not (buffer-live-p buf)))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-undead-buffer-should-bury ()
+  "Killing an undead buffer should bury it instead."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((orig (copy-sequence cj/undead-buffer-list))
+            (buf (generate-new-buffer "*test-undead*")))
+        (unwind-protect
+            (progn
+              (add-to-list 'cj/undead-buffer-list "*test-undead*")
+              (should (buffer-live-p buf))
+              (cj/kill-buffer-or-bury-alive buf)
+              (should (buffer-live-p buf)))
+          (setq cj/undead-buffer-list orig)
+          (when (buffer-live-p buf) (kill-buffer buf))))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-with-prefix-arg-should-add-to-undead-list ()
+  "Calling with prefix arg should add buffer to undead list."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((orig (copy-sequence cj/undead-buffer-list))
+            (buf (generate-new-buffer "*test-prefix*")))
+        (unwind-protect
+            (progn
+              (with-current-buffer buf
+                (let ((current-prefix-arg '(4)))
+                  (cj/kill-buffer-or-bury-alive buf)))
+              (should (member "*test-prefix*" cj/undead-buffer-list))
+              (should (buffer-live-p buf)))
+          (setq cj/undead-buffer-list orig)
+          (when (buffer-live-p buf) (kill-buffer buf))))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-scratch-buffer-should-bury ()
+  "The *scratch* buffer (in default list) should be buried."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((scratch (get-buffer-create "*scratch*")))
+        (should (buffer-live-p scratch))
+        (cj/kill-buffer-or-bury-alive scratch)
+        (should (buffer-live-p scratch)))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-kill-buffer-or-bury-alive-buffer-by-name-string-should-work ()
+  "Passing buffer name as string should work."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((buf (generate-new-buffer "*test-string*")))
+        (should (buffer-live-p buf))
+        (cj/kill-buffer-or-bury-alive "*test-string*")
+        (should-not (buffer-live-p buf)))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-buffer-by-buffer-object-should-work ()
+  "Passing buffer object should work."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((buf (generate-new-buffer "*test-object*")))
+        (should (buffer-live-p buf))
+        (cj/kill-buffer-or-bury-alive buf)
+        (should-not (buffer-live-p buf)))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-modified-undead-buffer-should-bury-without-prompt ()
+  "Modified undead buffer should be buried without save prompt."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((orig (copy-sequence cj/undead-buffer-list))
+            (buf (generate-new-buffer "*test-modified*")))
+        (unwind-protect
+            (progn
+              (add-to-list 'cj/undead-buffer-list "*test-modified*")
+              (with-current-buffer buf
+                (insert "some text")
+                (set-buffer-modified-p t))
+              (cj/kill-buffer-or-bury-alive buf)
+              (should (buffer-live-p buf)))
+          (setq cj/undead-buffer-list orig)
+          (when (buffer-live-p buf)
+            (set-buffer-modified-p nil)
+            (kill-buffer buf))))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+;;; Error Cases
+
+(ert-deftest test-kill-buffer-or-bury-alive-nonexistent-buffer-should-error ()
+  "Passing a non-existent buffer name should error."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (should-error (cj/kill-buffer-or-bury-alive "*nonexistent-buffer-xyz*"))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(ert-deftest test-kill-buffer-or-bury-alive-killed-buffer-object-should-error ()
+  "Passing a killed buffer object should error."
+  (test-kill-buffer-or-bury-alive-setup)
+  (unwind-protect
+      (let ((buf (generate-new-buffer "*test-killed*")))
+        (kill-buffer buf)
+        (should-error (cj/kill-buffer-or-bury-alive buf)))
+    (test-kill-buffer-or-bury-alive-teardown)))
+
+(provide 'test-undead-buffers-kill-buffer-or-bury-alive)
+;;; test-undead-buffers-kill-buffer-or-bury-alive.el ends here