feat(ai-conversations-browser): dired-style browser for saved GPTel conversations

`cj/gptel-load-conversation` prompts via `completing-read`.  A
dedicated browser shows what each conversation is about at a
glance and supports single-key load / delete / rename without
having to scroll a minibuffer list.

New module `modules/ai-conversations-browser.el` +
`cj/gptel-browse-conversations` entry point bound to `C-; a b`
("browse conversations").  Opens `*GPTel-Conversations*` in
`cj/gptel-browser-mode` (a `special-mode` derivative).

Each row shows date, time, topic slug, and a preview of the most
recent message (length configurable via
`cj/gptel-browser-preview-length`, default 60 chars).  Rows sort
newest first.

In the browser:
- `RET` / `l`: load the conversation (delegates to
  `cj/gptel-load-conversation` with the file pre-selected via a
  `cl-letf` stub on `completing-read` so the user isn't prompted
  twice), then bury the window.
- `d`: delete the file under point after `y-or-n-p` confirmation,
  re-render.
- `r`: rename the file under point.  Preserves the timestamp,
  slugifies the new topic, refuses unchanged input and existing
  targets.
- `g`: refresh.
- `n` / `p`: next / previous row.
- `q`: quit-window.

21 tests cover the helpers (topic parsing, header stripping,
preview shaping for truncate / short / empty cases, row-for-file
with conversation + non-conversation filenames, rows enumeration,
render output for empty + populated cases, newest-first sort,
rename-target preservation of timestamp + slug, rename-target
error on missing timestamp) and the file-touching actions (delete
with y, cancel with n, rename, rename-on-empty-line error).

1 files changed, 244 insertions, 0 deletions

diff --git a/tests/test-ai-conversations-browser.el b/tests/test-ai-conversations-browser.el
new file mode 100644
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+++ b/tests/test-ai-conversations-browser.el
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+;;; test-ai-conversations-browser.el --- Tests for ai-conversations-browser -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for the saved-conversations browser.  Pure helpers (topic
+;; parsing, header stripping, preview, rename target) are tested
+;; against fixed inputs.  File-touching actions (load / delete /
+;; rename) are tested against a temp conversations directory.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "tests" user-emacs-directory))
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+
+(require 'testutil-ai-config)
+;; Force real ai-conversations to override testutil's stub.
+(setq features (delq 'ai-conversations features))
+(require 'ai-conversations)
+(require 'ai-conversations-browser)
+
+;; ----------------------------- temp-dir helper
+
+(defun test-ai-conversations-browser--with-temp-dir (fn)
+  "Run FN inside a fresh conversations directory.  Clean up after."
+  (let* ((dir (make-temp-file "test-ai-conversations-browser-" t))
+         (cj/gptel-conversations-directory dir))
+    (unwind-protect
+        (funcall fn dir)
+      (when (file-exists-p dir)
+        (delete-directory dir t)))))
+
+(defun test-ai-conversations-browser--write (dir name content)
+  "Write CONTENT to NAME in DIR.  Return the absolute path."
+  (let ((path (expand-file-name name dir)))
+    (with-temp-file path (insert content))
+    path))
+
+;; ----------------------------- topic-from-filename
+
+(ert-deftest test-ai-conversations-browser-topic-normal ()
+  "Normal: topic slug extracted from a well-formed filename."
+  (should (equal (cj/gptel-browser--topic-from-filename
+                  "my-topic_20260315-101530.gptel")
+                 "my-topic")))
+
+(ert-deftest test-ai-conversations-browser-topic-error-malformed ()
+  "Boundary: malformed filename returns nil."
+  (should-not (cj/gptel-browser--topic-from-filename "garbage.gptel"))
+  (should-not (cj/gptel-browser--topic-from-filename "topic.gptel"))
+  (should-not (cj/gptel-browser--topic-from-filename "topic_20260315.gptel")))
+
+;; ----------------------------- strip-headers
+
+(ert-deftest test-ai-conversations-browser-strip-headers-normal ()
+  "Strip the two visibility headers plus the blank line after them."
+  (should (equal (cj/gptel-browser--strip-headers
+                  "#+STARTUP: showeverything\n#+VISIBILITY: all\n\nrest\n")
+                 "rest\n")))
+
+(ert-deftest test-ai-conversations-browser-strip-headers-no-headers ()
+  "Boundary: input without headers is unchanged."
+  (should (equal (cj/gptel-browser--strip-headers "plain body\n")
+                 "plain body\n")))
+
+;; ----------------------------- last-message
+
+(ert-deftest test-ai-conversations-browser-last-message-normal ()
+  "Last-message picks the body of the last org heading."
+  (let ((text "* user [2026-01-01]\nhello there\n* AI [2026-01-01]\nthe latest reply\n"))
+    (should (equal (cj/gptel-browser--last-message text)
+                   "the latest reply"))))
+
+(ert-deftest test-ai-conversations-browser-last-message-no-heading ()
+  "Boundary: text without headings returns the (collapsed) body."
+  (let ((text "just some body\nwith two lines\n"))
+    (should (equal (cj/gptel-browser--last-message text)
+                   "just some body with two lines"))))
+
+;; ----------------------------- preview
+
+(ert-deftest test-ai-conversations-browser-preview-truncates ()
+  "Preview is ellipsized when the message is longer than LENGTH."
+  (let ((text "* AI\nthis is a very long response that should get truncated for the preview\n"))
+    (let ((preview (cj/gptel-browser--preview text 30)))
+      (should (= (length preview) 30))
+      (should (string-suffix-p "…" preview)))))
+
+(ert-deftest test-ai-conversations-browser-preview-short ()
+  "Preview is returned verbatim when shorter than LENGTH."
+  (let ((text "* AI\nshort\n"))
+    (should (equal (cj/gptel-browser--preview text 60) "short"))))
+
+(ert-deftest test-ai-conversations-browser-preview-empty ()
+  "Preview of empty body returns empty string."
+  (should (equal (cj/gptel-browser--preview "" 60) "")))
+
+;; ----------------------------- row-for-file
+
+(ert-deftest test-ai-conversations-browser-row-for-file-normal ()
+  "Row contains date, topic, and a preview; carries file metadata."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (let ((file (test-ai-conversations-browser--write
+                  dir "alpha_20260315-101530.gptel"
+                  "#+STARTUP: showeverything\n\n* AI\nresult body\n")))
+       (let ((row (cj/gptel-browser--row-for-file file dir)))
+         (should row)
+         (should (string-match-p "2026-03-15 10:15" row))
+         (should (string-match-p "alpha" row))
+         (should (string-match-p "result body" row))
+         (should (equal (get-text-property 0 'cj/gptel-browser-file row)
+                        "alpha_20260315-101530.gptel")))))))
+
+(ert-deftest test-ai-conversations-browser-row-for-file-non-conversation ()
+  "Files that don't match the conversation pattern return nil."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (let ((file (test-ai-conversations-browser--write
+                  dir "not-a-conversation.gptel" "body")))
+       (should-not (cj/gptel-browser--row-for-file file dir))))))
+
+;; ----------------------------- rows / render
+
+(ert-deftest test-ai-conversations-browser-rows-from-empty-dir ()
+  "Empty conversations directory yields no rows."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (_dir)
+     (should-not (cj/gptel-browser--rows)))))
+
+(ert-deftest test-ai-conversations-browser-rows-multiple-conversations ()
+  "Multiple conversations produce a row per file."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (test-ai-conversations-browser--write
+      dir "a_20260101-100000.gptel" "* AI\nfirst\n")
+     (test-ai-conversations-browser--write
+      dir "b_20260102-100000.gptel" "* AI\nsecond\n")
+     (let ((rows (cj/gptel-browser--rows)))
+       (should (= 2 (length rows)))))))
+
+(ert-deftest test-ai-conversations-browser-render-empty ()
+  "Render shows a 'no conversations' line when directory is empty."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (_dir)
+     (with-temp-buffer
+       (cj/gptel-browser-mode)
+       (cj/gptel-browser--render)
+       (should (string-match-p "no saved conversations" (buffer-string)))))))
+
+(ert-deftest test-ai-conversations-browser-render-newest-first ()
+  "Render sorts rows newest first by timestamp."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (test-ai-conversations-browser--write
+      dir "old_20260101-100000.gptel" "* AI\nx\n")
+     (test-ai-conversations-browser--write
+      dir "new_20260301-100000.gptel" "* AI\ny\n")
+     (with-temp-buffer
+       (cj/gptel-browser-mode)
+       (cj/gptel-browser--render)
+       (let ((text (buffer-substring-no-properties (point-min) (point-max))))
+         ;; New (March) should appear before old (January) in the buffer.
+         (should (< (string-match "2026-03-01" text)
+                    (string-match "2026-01-01" text))))))))
+
+;; ----------------------------- rename-target
+
+(ert-deftest test-ai-conversations-browser-rename-target-normal ()
+  "Rename-target preserves the timestamp and slugifies the new topic."
+  (should (equal (cj/gptel-browser--rename-target
+                  "/tmp/old-topic_20260101-100000.gptel"
+                  "Brand New Topic")
+                 "/tmp/brand-new-topic_20260101-100000.gptel")))
+
+(ert-deftest test-ai-conversations-browser-rename-target-error-no-timestamp ()
+  "Rename-target errors when the filename lacks a timestamp."
+  (should-error (cj/gptel-browser--rename-target "/tmp/no-ts.gptel" "x")))
+
+;; ----------------------------- delete / rename actions
+
+(ert-deftest test-ai-conversations-browser-delete-removes-file ()
+  "Delete with y removes the file under point and re-renders."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (let ((file (test-ai-conversations-browser--write
+                  dir "topic_20260101-100000.gptel" "* AI\nx\n")))
+       (with-temp-buffer
+         (cj/gptel-browser-mode)
+         (cj/gptel-browser--render)
+         ;; Point on the only data row
+         (goto-char (point-min))
+         (forward-line 2)
+         (cl-letf (((symbol-function 'y-or-n-p) (lambda (&rest _) t)))
+           (cj/gptel-browser-delete))
+         (should-not (file-exists-p file)))))))
+
+(ert-deftest test-ai-conversations-browser-delete-cancel-keeps-file ()
+  "Delete with n leaves the file alone."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (let ((file (test-ai-conversations-browser--write
+                  dir "topic_20260101-100000.gptel" "* AI\nx\n")))
+       (with-temp-buffer
+         (cj/gptel-browser-mode)
+         (cj/gptel-browser--render)
+         (goto-char (point-min))
+         (forward-line 2)
+         (cl-letf (((symbol-function 'y-or-n-p) (lambda (&rest _) nil)))
+           (cj/gptel-browser-delete))
+         (should (file-exists-p file)))))))
+
+(ert-deftest test-ai-conversations-browser-rename-renames-file ()
+  "Rename moves the file under a new slug while preserving timestamp."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (dir)
+     (let* ((file (test-ai-conversations-browser--write
+                   dir "old-name_20260101-100000.gptel" "* AI\nx\n")))
+       (with-temp-buffer
+         (cj/gptel-browser-mode)
+         (cj/gptel-browser--render)
+         (goto-char (point-min))
+         (forward-line 2)
+         (cl-letf (((symbol-function 'read-string)
+                    (lambda (&rest _) "renamed topic")))
+           (cj/gptel-browser-rename))
+         (should-not (file-exists-p file))
+         (should (file-exists-p
+                  (expand-file-name "renamed-topic_20260101-100000.gptel"
+                                    dir))))))))
+
+(ert-deftest test-ai-conversations-browser-rename-error-on-empty-line ()
+  "Rename errors when point is on the header/empty area."
+  (test-ai-conversations-browser--with-temp-dir
+   (lambda (_dir)
+     (with-temp-buffer
+       (cj/gptel-browser-mode)
+       (cj/gptel-browser--render)
+       (goto-char (point-min))
+       (should-error (cj/gptel-browser-rename))))))
+
+(provide 'test-ai-conversations-browser)
+;;; test-ai-conversations-browser.el ends here