feat(ai-vterm): add Claude launcher with vertical-split vterm

The new module picks a Claude-template project from a filtered completing-read list. It scans the same roots the `ai` shell launcher uses, then opens or reuses a vterm buffer named `claude [<repo>]` on the right. F9 launches it. The prior `cj/toggle-gptel` binding moves from F9 to C-F9 so both AI tools share the same physical key.

The display rule chains reuse-window -> use-some-window -> in-direction (right). The resulting window isn't dedicated. That matters because side-window dedication was breaking `buffer-move` (C-M-arrows) and `switch-to-buffer` replacement on the claude buffer. I also narrowed `vterm-toggle`'s display rule to skip `claude [` buffers. Otherwise it claimed them first with its bottom-split + dedicated treatment.

I added 23 tests across 5 files: the buffer-name transform, candidate walker, show-or-create dispatch, picker, and display rule. Design lives at docs/design/ai-vterm.org.

1 files changed, 119 insertions, 0 deletions

diff --git a/tests/test-ai-vterm--show-or-create.el b/tests/test-ai-vterm--show-or-create.el
new file mode 100644
index 00000000..28e0faeb
--- /dev/null
+++ b/tests/test-ai-vterm--show-or-create.el
@@ -0,0 +1,119 @@
+;;; test-ai-vterm--show-or-create.el --- Tests for cj/--ai-vterm-show-or-create -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests the show-or-create branching:
+;;
+;; - buffer absent          -> vterm called, claude command sent
+;; - buffer present, live   -> vterm not called, buffer displayed
+;; - buffer present, dead   -> old buffer killed, vterm recreates
+;;
+;; vterm functions are stubbed so the test does no process spawning.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ai-vterm)
+
+;; vterm isn't loaded in batch -- provide stubs so cl-letf has overrides.
+(unless (fboundp 'vterm)
+  (defun vterm (&optional _name) nil))
+(unless (fboundp 'vterm-send-string)
+  (defun vterm-send-string (_s &optional _) nil))
+(unless (fboundp 'vterm-send-return)
+  (defun vterm-send-return () nil))
+
+(defmacro test-ai-vterm--with-mock-vterm (vars &rest body)
+  "Run BODY with vterm + send-string + send-return mocked.
+
+VARS is a plist of capture variable names: :calls, :strings, :returns,
+:default-dir.  The test references these names directly inside BODY."
+  (declare (indent 1) (debug t))
+  (let ((calls (plist-get vars :calls))
+        (strings (plist-get vars :strings))
+        (returns (plist-get vars :returns))
+        (ddir (plist-get vars :default-dir)))
+    `(let ((,calls '())
+           (,strings '())
+           (,returns 0)
+           (,ddir nil))
+       (cl-letf (((symbol-function 'vterm)
+                  (lambda (&optional name)
+                    (push name ,calls)
+                    (setq ,ddir default-directory)
+                    (with-current-buffer (get-buffer-create name)
+                      (current-buffer))))
+                 ((symbol-function 'vterm-send-string)
+                  (lambda (s &optional _) (push s ,strings)))
+                 ((symbol-function 'vterm-send-return)
+                  (lambda () (cl-incf ,returns))))
+         ,@body))))
+
+(defun test-ai-vterm--cleanup (name)
+  "Kill buffer NAME if it exists."
+  (when (get-buffer name)
+    (kill-buffer name)))
+
+(ert-deftest test-ai-vterm--show-or-create-creates-when-buffer-missing ()
+  "Normal: no existing buffer -> vterm called once, claude cmd sent."
+  (let ((name "claude [normal-create-test]"))
+    (test-ai-vterm--cleanup name)
+    (unwind-protect
+        (test-ai-vterm--with-mock-vterm (:calls calls :strings strings
+                                         :returns returns :default-dir ddir)
+          (cj/--ai-vterm-show-or-create "/tmp/some-project" name)
+          (should (equal calls (list name)))
+          (should (equal strings (list cj/ai-vterm-claude-command)))
+          (should (= returns 1))
+          (should (equal ddir "/tmp/some-project")))
+      (test-ai-vterm--cleanup name))))
+
+(ert-deftest test-ai-vterm--show-or-create-displays-existing-when-process-live ()
+  "Normal: buffer exists with live process -> vterm not called."
+  (let ((name "claude [reuse-test]"))
+    (test-ai-vterm--cleanup name)
+    (unwind-protect
+        (let ((buf (get-buffer-create name)))
+          (cl-letf (((symbol-function 'cj/--ai-vterm-process-live-p)
+                     (lambda (b) (and (eq b buf) t))))
+            (test-ai-vterm--with-mock-vterm (:calls calls :strings strings
+                                             :returns returns :default-dir _ddir)
+              (cj/--ai-vterm-show-or-create "/tmp/reuse" name)
+              (should (null calls))
+              (should (null strings))
+              (should (= returns 0)))))
+      (test-ai-vterm--cleanup name))))
+
+(ert-deftest test-ai-vterm--show-or-create-recreates-when-process-dead ()
+  "Boundary: buffer exists with dead process -> killed and recreated."
+  (let ((name "claude [dead-test]"))
+    (test-ai-vterm--cleanup name)
+    (unwind-protect
+        (let ((stale (get-buffer-create name)))
+          (cl-letf (((symbol-function 'cj/--ai-vterm-process-live-p)
+                     (lambda (_b) nil)))
+            (test-ai-vterm--with-mock-vterm (:calls calls :strings strings
+                                             :returns returns :default-dir _ddir)
+              (cj/--ai-vterm-show-or-create "/tmp/dead" name)
+              (should (equal calls (list name)))
+              (should (equal strings (list cj/ai-vterm-claude-command)))
+              (should (= returns 1))
+              (should-not (buffer-live-p stale)))))
+      (test-ai-vterm--cleanup name))))
+
+(ert-deftest test-ai-vterm--show-or-create-returns-buffer ()
+  "Normal: return value is the vterm buffer."
+  (let ((name "claude [return-test]"))
+    (test-ai-vterm--cleanup name)
+    (unwind-protect
+        (test-ai-vterm--with-mock-vterm (:calls _c :strings _s
+                                         :returns _r :default-dir _d)
+          (let ((result (cj/--ai-vterm-show-or-create "/tmp/return" name)))
+            (should (bufferp result))
+            (should (equal (buffer-name result) name))))
+      (test-ai-vterm--cleanup name))))
+
+(provide 'test-ai-vterm--show-or-create)
+;;; test-ai-vterm--show-or-create.el ends here