1 files changed, 103 insertions, 0 deletions
diff --git a/tests/test-vterm-toggle--buffer-filter.el b/tests/test-vterm-toggle--buffer-filter.el
new file mode 100644
index 00000000..8deb9066
--- /dev/null
+++ b/tests/test-vterm-toggle--buffer-filter.el
@@ -0,0 +1,103 @@
+;;; test-vterm-toggle--buffer-filter.el --- Tests for F12's buffer filter -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Three closely-related helpers determine which vterm buffers F12
+;; manages: the predicate `cj/--vterm-toggle-buffer-p', the MRU list
+;; `cj/--vterm-toggle-buffers', and the per-frame window finder
+;; `cj/--vterm-toggle-displayed-window'.  All three exclude claude-
+;; prefixed buffers so claude has its own F9 surface.
+
+;;; Code:
+
+(require 'ert)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'eshell-vterm-config)
+
+(defun test-vterm-toggle--cleanup ()
+  "Kill any test-prefixed vterm-style buffers left behind."
+  (dolist (b (buffer-list))
+    (let ((name (buffer-name b)))
+      (when (or (string-prefix-p "*test-vterm" name)
+                (string-prefix-p "claude [" name))
+        (kill-buffer b)))))
+
+(defun test-vterm-toggle--make-vterm-buffer (name)
+  "Create BUFFER with vterm-mode for testing.
+Avoids actually launching a vterm process by manually setting major-mode."
+  (let ((buf (get-buffer-create name)))
+    (with-current-buffer buf
+      (setq-local major-mode 'vterm-mode))
+    buf))
+
+(ert-deftest test-vterm-toggle--buffer-p-accepts-vterm-mode ()
+  "Normal: a vterm-mode buffer with non-claude name qualifies."
+  (test-vterm-toggle--cleanup)
+  (let ((buf (test-vterm-toggle--make-vterm-buffer "*test-vterm-1*")))
+    (unwind-protect
+        (should (cj/--vterm-toggle-buffer-p buf))
+      (kill-buffer buf))))
+
+(ert-deftest test-vterm-toggle--buffer-p-rejects-claude ()
+  "Boundary: claude-prefixed vterm buffers are excluded from F12's set."
+  (test-vterm-toggle--cleanup)
+  (let ((buf (test-vterm-toggle--make-vterm-buffer "claude [project-a]")))
+    (unwind-protect
+        (should-not (cj/--vterm-toggle-buffer-p buf))
+      (kill-buffer buf))))
+
+(ert-deftest test-vterm-toggle--buffer-p-rejects-non-vterm ()
+  "Boundary: a regular buffer (not vterm-mode, no vterm name prefix) -> nil."
+  (test-vterm-toggle--cleanup)
+  (let ((buf (get-buffer-create "*test-vterm-regular*")))
+    (unwind-protect
+        (should-not (cj/--vterm-toggle-buffer-p buf))
+      (kill-buffer buf))))
+
+(ert-deftest test-vterm-toggle--buffer-p-rejects-dead-buffer ()
+  "Boundary: nil and dead buffers -> nil."
+  (should-not (cj/--vterm-toggle-buffer-p nil))
+  (let ((buf (test-vterm-toggle--make-vterm-buffer "*test-vterm-dead*")))
+    (kill-buffer buf)
+    (should-not (cj/--vterm-toggle-buffer-p buf))))
+
+(ert-deftest test-vterm-toggle--buffers-filters-claude ()
+  "Normal: returns vterm buffers but excludes claude-prefixed ones."
+  (test-vterm-toggle--cleanup)
+  (let ((normal (test-vterm-toggle--make-vterm-buffer "*test-vterm-normal*"))
+        (claude (test-vterm-toggle--make-vterm-buffer "claude [for-test]")))
+    (unwind-protect
+        (let ((result (cj/--vterm-toggle-buffers)))
+          (should (memq normal result))
+          (should-not (memq claude result)))
+      (kill-buffer normal)
+      (kill-buffer claude))))
+
+(ert-deftest test-vterm-toggle--displayed-window-finds-vterm ()
+  "Normal: vterm in a window -> returns that window."
+  (test-vterm-toggle--cleanup)
+  (let ((vt (test-vterm-toggle--make-vterm-buffer "*test-vterm-shown*")))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((win (split-window-right)))
+            (set-window-buffer win vt)
+            (let ((result (cj/--vterm-toggle-displayed-window)))
+              (should (windowp result))
+              (should (eq (window-buffer result) vt)))))
+      (kill-buffer vt))))
+
+(ert-deftest test-vterm-toggle--displayed-window-skips-claude ()
+  "Boundary: only a claude vterm is displayed -> nil (claude not F12-managed)."
+  (test-vterm-toggle--cleanup)
+  (let ((claude (test-vterm-toggle--make-vterm-buffer "claude [skip-test]")))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((win (split-window-right)))
+            (set-window-buffer win claude)
+            (should-not (cj/--vterm-toggle-displayed-window))))
+      (kill-buffer claude))))
+
+(provide 'test-vterm-toggle--buffer-filter)
+;;; test-vterm-toggle--buffer-filter.el ends here