Use lexical-binding in cal-julian.el and add tests

* lisp/calendar/cal-julian.el: Use lexical-binding.
* test/lisp/calendar/cal-julian-tests.el: New file.

lisp/calendar/cal-julian.el

@@ -1,4 +1,4 @@
-;;; cal-julian.el --- calendar functions for the Julian calendar
+;;; cal-julian.el --- calendar functions for the Julian calendar  -*- lexical-binding:t -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2020 Free Software Foundation, Inc.
 

test/lisp/calendar/cal-julian-tests.el

@@ -0,0 +1,72 @@
+;;; cal-julian-tests.el --- tests for calendar/cal-julian.el  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2020 Free Software Foundation, Inc.
+
+;; Author: Stefan Kangas <stefankangas@gmail.com>
+
+;; 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/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'cal-julian)
+
+(ert-deftest cal-julian-test-to-absolute ()
+  (should (equal (calendar-gregorian-from-absolute
+                  (calendar-julian-to-absolute
+                   '(10 25 1917)))
+                 '(11 7 1917))))
+
+(ert-deftest cal-julian-test-from-absolute ()
+  (should (equal (calendar-julian-from-absolute
+                  (calendar-absolute-from-gregorian
+                   '(11 7 1917)))
+                 '(10 25 1917))))
+
+(ert-deftest cal-julian-test-date-string ()
+  (should (equal (let ((calendar-date-display-form calendar-iso-date-display-form))
+                   (calendar-julian-date-string '(11 7 1917)))
+                 "1917-10-25")))
+
+(defmacro with-cal-julian-test (&rest body)
+  `(save-window-excursion
+     (unwind-protect
+         (progn
+           (calendar)
+           ,@body)
+       (kill-buffer "*Calendar*"))))
+
+(ert-deftest cal-julian-test-goto-date ()
+  (with-cal-julian-test
+   (calendar-julian-goto-date '(10 25 1917))
+   (should (looking-at "7"))))
+
+(ert-deftest cal-julian-test-astro-to-and-from-absolute ()
+  (should (= (+ (calendar-astro-to-absolute 0.0)
+                (calendar-astro-from-absolute 0.0))
+             0.0)))
+
+(ert-deftest cal-julian-calendar-astro-date-string ()
+  (should (equal (calendar-astro-date-string '(10 25 1917)) "2421527")))
+
+(ert-deftest calendar-astro-goto-day-number ()
+  (with-cal-julian-test
+   (calendar-astro-goto-day-number 2421527)
+   (backward-char)
+   (should (looking-at "25"))))
+
+(provide 'cal-julian-tests)
+;;; cal-julian-tests.el ends here