ert-x: Move window selection logic to its own macro

* lisp/emacs-lisp/ert-x.el (ert-with-buffer-selected): New macro to
temporarily display a buffer in a selected window and evaluate a body.
(ert-with-test-buffer-selected): Use the new macro.
* test/lisp/whitespace-tests.el
(ert-test-with-buffer-selected/current)
(ert-test-with-buffer-selected/selected)
(ert-test-with-buffer-selected/nil-buffer)
(ert-test-with-buffer-selected/modification-hooks)
(ert-test-with-buffer-selected/read-only)
(ert-test-with-buffer-selected/return-value): Add tests.
(Bug#60189)

1 files changed, 34 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/ert-x-tests.el b/test/lisp/emacs-lisp/ert-x-tests.el
index f14d54cd9f7..1cfd218592a 100644
--- a/test/lisp/emacs-lisp/ert-x-tests.el
+++ b/test/lisp/emacs-lisp/ert-x-tests.el
@@ -82,6 +82,40 @@
         (should-not (buffer-live-p buffer-1))
         (should (buffer-live-p buffer-2))))))
 
+(ert-deftest ert-test-with-buffer-selected/current ()
+  (let ((origbuf (current-buffer)))
+    (ert-with-test-buffer ()
+      (let ((buf (current-buffer)))
+        (should (not (eq buf origbuf)))
+        (with-current-buffer origbuf
+          (ert-with-buffer-selected buf
+            (should (eq (current-buffer) buf))))))))
+
+(ert-deftest ert-test-with-buffer-selected/selected ()
+  (ert-with-test-buffer ()
+    (ert-with-buffer-selected (current-buffer)
+      (should (eq (window-buffer) (current-buffer))))))
+
+(ert-deftest ert-test-with-buffer-selected/nil-buffer ()
+  (ert-with-test-buffer ()
+    (let ((buf (current-buffer)))
+      (ert-with-buffer-selected nil
+        (should (eq (window-buffer) buf))))))
+
+(ert-deftest ert-test-with-buffer-selected/modification-hooks ()
+  (ert-with-test-buffer ()
+    (ert-with-buffer-selected (current-buffer)
+      (should (null inhibit-modification-hooks)))))
+
+(ert-deftest ert-test-with-buffer-selected/read-only ()
+  (ert-with-test-buffer ()
+    (ert-with-buffer-selected (current-buffer)
+      (should (null inhibit-read-only))
+      (should (null buffer-read-only)))))
+
+(ert-deftest ert-test-with-buffer-selected/return-value ()
+  (should (equal (ert-with-buffer-selected nil "foo") "foo")))
+
 (ert-deftest ert-test-with-test-buffer-selected/selected ()
   (ert-with-test-buffer-selected ()
     (should (eq (window-buffer) (current-buffer)))))