Load desktop without prompting if process is dead

* doc/emacs/misc.texi (Saving Emacs Sessions): Document the new
'check' value.
* etc/NEWS: Announce the change (bug#1474).
* lisp/desktop.el (desktop-load-locked-desktop): Add new value 'check'
to load desktop file without prompting if locking Emacs process does
not exist on the local machine.  (Bug#1474)
(desktop-read): Extract function from here...
(desktop--load-locked-desktop-p): ...to here.  New function handles
the semantics of 'desktop-load-locked-desktop', including above new
value 'check'.
(desktop--emacs-pid-running-p): New function.

* test/lisp/desktop-tests.el: New file with tests for the above.

1 files changed, 50 insertions, 0 deletions

diff --git a/test/lisp/desktop-tests.el b/test/lisp/desktop-tests.el
new file mode 100644
index 00000000000..d52fe39ed96
--- /dev/null
+++ b/test/lisp/desktop-tests.el
@@ -0,0 +1,50 @@
+;;; desktop-tests.el --- Tests for desktop.el  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2020 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs 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.
+
+;; GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'desktop)
+
+(ert-deftest desktop-tests--emacs-pid-running-p ()
+  (should (desktop--emacs-pid-running-p (emacs-pid)))
+  (should-not (desktop--emacs-pid-running-p 1)))
+
+(ert-deftest desktop-tests--load-locked-desktop-p ()
+  (let ((desktop-load-locked-desktop t))
+    (should (desktop--load-locked-desktop-p (emacs-pid)))))
+
+(ert-deftest desktop-tests--load-locked-desktop-p-nil ()
+  (let ((desktop-load-locked-desktop nil))
+    (should-not (desktop--load-locked-desktop-p (emacs-pid)))))
+
+(ert-deftest desktop-tests--load-locked-desktop-p-ask ()
+ (let ((desktop-load-locked-desktop 'ask))
+   (cl-letf (((symbol-function 'y-or-n-p) (lambda (&rest _) t)))
+     (should (desktop--load-locked-desktop-p (emacs-pid))))
+   (cl-letf (((symbol-function 'y-or-n-p) (lambda (&rest _) nil)))
+     (should-not (desktop--load-locked-desktop-p (emacs-pid))))))
+
+(ert-deftest desktop-tests--load-locked-desktop-p-check ()
+  (let ((desktop-load-locked-desktop 'check-pid))
+    (desktop--load-locked-desktop-p (emacs-pid))))
+
+(provide 'desktop-tests)