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+;;; test-pearl-surface.el --- Tests for surfacing the active buffer -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Craig Jennings
+
+;; Author: Craig Jennings <c@cjennings.net>
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for `pearl--surface-buffer': bring the active org buffer to a window
+;; after a command updates it, gated on `pearl-surface-buffer', focus-following
+;; gated on `pearl-surface-select-window', and skipped when the buffer is dead
+;; or already visible.
+
+;;; Code:
+
+(require 'test-bootstrap (expand-file-name "test-bootstrap.el"))
+(require 'cl-lib)
+
+(ert-deftest test-pearl-surface-buffer-disabled-is-noop ()
+  "With `pearl-surface-buffer' nil, nothing is displayed."
+  (let ((pearl-surface-buffer nil) (shown nil))
+    (cl-letf (((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
+              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
+      (with-temp-buffer
+        (pearl--surface-buffer (current-buffer))
+        (should-not shown)))))
+
+(ert-deftest test-pearl-surface-buffer-shows-when-buried ()
+  "A live, un-displayed buffer is shown via `display-buffer' by default."
+  (let ((pearl-surface-buffer t) (pearl-surface-select-window nil) (shown nil))
+    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) nil))
+              ((symbol-function 'display-buffer) (lambda (b &rest _) (setq shown b)))
+              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown 'pop))))
+      (with-temp-buffer
+        (pearl--surface-buffer (current-buffer))
+        (should (eq shown (current-buffer)))))))
+
+(ert-deftest test-pearl-surface-buffer-skips-when-already-shown ()
+  "A buffer already visible in some window is left alone."
+  (let ((pearl-surface-buffer t) (shown nil))
+    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) 'a-window))
+              ((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
+              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
+      (with-temp-buffer
+        (pearl--surface-buffer (current-buffer))
+        (should-not shown)))))
+
+(ert-deftest test-pearl-surface-buffer-select-window-uses-pop-to-buffer ()
+  "With `pearl-surface-select-window' non-nil, focus follows via `pop-to-buffer'."
+  (let ((pearl-surface-buffer t) (pearl-surface-select-window t) (how nil))
+    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) nil))
+              ((symbol-function 'display-buffer) (lambda (&rest _) (setq how 'display)))
+              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq how 'pop))))
+      (with-temp-buffer
+        (pearl--surface-buffer (current-buffer))
+        (should (eq how 'pop))))))
+
+(ert-deftest test-pearl-surface-buffer-dead-buffer-is-noop ()
+  "A killed buffer is never surfaced."
+  (let ((pearl-surface-buffer t) (shown nil) (buf (generate-new-buffer "x")))
+    (kill-buffer buf)
+    (cl-letf (((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
+              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
+      (pearl--surface-buffer buf)
+      (should-not shown))))
+
+(provide 'test-pearl-surface)
+;;; test-pearl-surface.el ends here