test(gptel-tools): cover the helpers across the five remaining tools

The gptel-tools files had zero direct coverage outside of
`update_text_file`, which landed with its rewrite earlier this
session.  This commit adds 52 tests across the five other tools.

For three of the tools the helpers were already top-level defuns
(`read_text_file`, `list_directory_files`, `move_to_trash`).  The
other two had their main bodies inlined into the `gptel-make-tool`
lambda -- I extracted them so the work is testable without mocking
gptel itself:

  read_buffer.el     -> `cj/read-buffer--get-content`
  write_text_file.el -> `cj/write-text-file--run` plus
                        `--validate-path`, `--backup-name`,
                        `--ensure-parent`

Test files, by tool:

- read_buffer.el          (5 tests):  normal, empty, buffer-object,
  text-property-stripping, missing buffer.
- write_text_file.el     (10 tests):  validate-path, backup-name
  shape, ensure-parent (creates missing / rejects unwritable), run
  with normal / overwrite / existing-no-overwrite / empty content /
  outside-home.
- read_text_file.el      (12 tests):  validate-file-path (normal +
  three error shapes), metadata plist shape, size limits (no-op /
  hard cap / warning bypass with no-confirm), binary detection
  (text vs null-byte), special-type EPUB and generic-binary paths.
- list_directory_files.el (15 tests):  mode-to-permissions (file /
  dir / executable), get-file-info (file / directory), extension
  filter (keep / drop / always-dir / nil-extension), format-file-
  entry, list-directory flat / recursive / error, format-output
  with and without files.
- move_to_trash.el       (10 tests):  unique-name (no conflict /
  conflict with timestamp / no-extension), validate-path (HOME / /tmp
  / outside / critical-dir / missing), perform on file and
  directory.

Each test file uses the same load-path / gptel-stub idiom
(`eval-and-compile` block, gptel stub when the real package isn't
available) so the byte-compile hook is happy.

1 files changed, 136 insertions, 0 deletions

diff --git a/tests/test-gptel-tools-move-to-trash.el b/tests/test-gptel-tools-move-to-trash.el
new file mode 100644
index 00000000..a6ab1200
--- /dev/null
+++ b/tests/test-gptel-tools-move-to-trash.el
@@ -0,0 +1,136 @@
+;;; test-gptel-tools-move-to-trash.el --- Tests for move_to_trash gptel tool -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for the helpers in move_to_trash.el.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(eval-and-compile
+  (add-to-list 'load-path (expand-file-name "tests" user-emacs-directory))
+  (add-to-list 'load-path (expand-file-name "gptel-tools" user-emacs-directory))
+  (setq load-prefer-newer t)
+  (unless (featurep 'gptel)
+    (defvar gptel-tools nil)
+    (defun gptel-make-tool (&rest _args) nil)
+    (defun gptel-get-tool (&rest _args) nil)
+    (provide 'gptel)))
+
+(require 'move_to_trash)
+
+;; -------------------------- helpers
+
+(defun test-gptel-tools-trash--with-tmp-tree (fn)
+  "Create a temp source dir and trash dir; run FN with both; clean up."
+  (let* ((src (make-temp-file "test-gptel-tools-trash-src-" t))
+         (trash (make-temp-file "test-gptel-tools-trash-dst-" t)))
+    (unwind-protect
+        (funcall fn src trash)
+      (when (file-exists-p src) (delete-directory src t))
+      (when (file-exists-p trash) (delete-directory trash t)))))
+
+;; -------------------------- generate-unique-name
+
+(ert-deftest test-gptel-tools-trash-generate-unique-name-no-conflict ()
+  "No conflict: returns the plain base name in trash."
+  (test-gptel-tools-trash--with-tmp-tree
+   (lambda (_src trash)
+     (let ((out (gptel--move-to-trash-generate-unique-name
+                 "/anywhere/foo.txt" trash)))
+       (should (equal (file-name-nondirectory out) "foo.txt"))))))
+
+(ert-deftest test-gptel-tools-trash-generate-unique-name-conflict-timestamps ()
+  "Name conflict: returns a name with a timestamp suffix."
+  (test-gptel-tools-trash--with-tmp-tree
+   (lambda (_src trash)
+     (with-temp-file (expand-file-name "foo.txt" trash) (insert ""))
+     (let* ((out (gptel--move-to-trash-generate-unique-name
+                  "/anywhere/foo.txt" trash))
+            (name (file-name-nondirectory out)))
+       (should-not (equal name "foo.txt"))
+       (should (string-match-p "\\`foo-[0-9]\\{4\\}-[0-9]\\{2\\}-[0-9]\\{2\\}-[0-9]\\{2\\}-[0-9]\\{2\\}-[0-9]\\{2\\}\\.txt\\'"
+                               name))))))
+
+(ert-deftest test-gptel-tools-trash-generate-unique-name-no-extension ()
+  "Conflict on a name without extension: timestamp appended to the bare name."
+  (test-gptel-tools-trash--with-tmp-tree
+   (lambda (_src trash)
+     (with-temp-file (expand-file-name "noext" trash) (insert ""))
+     (let* ((out (gptel--move-to-trash-generate-unique-name
+                  "/anywhere/noext" trash))
+            (name (file-name-nondirectory out)))
+       (should-not (equal name "noext"))
+       (should (string-match-p "\\`noext-[0-9]" name))))))
+
+;; -------------------------- validate-path
+
+(ert-deftest test-gptel-tools-trash-validate-path-normal-home ()
+  "Normal: an existing path under HOME validates."
+  (let ((path (expand-file-name
+               (format ".test-gptel-tools-trash-home-%s.tmp"
+                       (format-time-string "%s%N"))
+               "~")))
+    (unwind-protect
+        (progn
+          (with-temp-file path (insert ""))
+          (should (equal (gptel--move-to-trash-validate-path path)
+                         (expand-file-name path))))
+      (when (file-exists-p path) (delete-file path)))))
+
+(ert-deftest test-gptel-tools-trash-validate-path-normal-tmp ()
+  "Normal: an existing path under /tmp validates."
+  (let ((path (make-temp-file "test-gptel-tools-trash-tmpvalidate-")))
+    (unwind-protect
+        (should (equal (gptel--move-to-trash-validate-path path)
+                       (expand-file-name path)))
+      (when (file-exists-p path) (delete-file path)))))
+
+(ert-deftest test-gptel-tools-trash-validate-path-error-outside-allowed ()
+  "Error: a path outside HOME or /tmp signals."
+  (should-error (gptel--move-to-trash-validate-path "/etc/hostname")))
+
+(ert-deftest test-gptel-tools-trash-validate-path-error-critical-dir ()
+  "Error: critical directories (home root, .emacs.d, .config, /tmp) signal."
+  (should-error (gptel--move-to-trash-validate-path "~"))
+  (should-error (gptel--move-to-trash-validate-path "~/.emacs.d"))
+  (should-error (gptel--move-to-trash-validate-path "~/.config"))
+  (should-error (gptel--move-to-trash-validate-path "/tmp")))
+
+(ert-deftest test-gptel-tools-trash-validate-path-error-missing ()
+  "Error: missing path signals."
+  (let ((path (expand-file-name
+               (format ".test-gptel-tools-trash-missing-%s.tmp"
+                       (format-time-string "%s%N"))
+               "~")))
+    (when (file-exists-p path) (delete-file path))
+    (should-error (gptel--move-to-trash-validate-path path))))
+
+;; -------------------------- perform
+
+(ert-deftest test-gptel-tools-trash-perform-moves-file ()
+  "Perform: moves the file out of the source dir into the trash dir."
+  (test-gptel-tools-trash--with-tmp-tree
+   (lambda (src trash)
+     (let ((file (expand-file-name "doomed.txt" src)))
+       (with-temp-file file (insert "trash me"))
+       (let ((status (gptel--move-to-trash-perform file trash)))
+         (should (string-match-p "moved to trash" status))
+         (should-not (file-exists-p file))
+         (should (file-exists-p (expand-file-name "doomed.txt" trash))))))))
+
+(ert-deftest test-gptel-tools-trash-perform-handles-directory ()
+  "Perform: moves a directory as a unit."
+  (test-gptel-tools-trash--with-tmp-tree
+   (lambda (src trash)
+     (let ((dir (expand-file-name "subdir" src)))
+       (make-directory dir)
+       (with-temp-file (expand-file-name "inside.txt" dir) (insert "x"))
+       (let ((status (gptel--move-to-trash-perform dir trash)))
+         (should (string-match-p "Directory moved to trash" status))
+         (should-not (file-exists-p dir))
+         (should (file-exists-p (expand-file-name "subdir/inside.txt" trash))))))))
+
+(provide 'test-gptel-tools-move-to-trash)
+;;; test-gptel-tools-move-to-trash.el ends here