time-equal, and time values of infinity and NaN

* doc/lispref/os.texi (Time Calculations):
Document time-equal, and the behavior on NaNs and infinities of
time-less-p, time-add, time-subtract.
* etc/NEWS: Mention the change.
* src/editfns.c (time_arith): Change last arg from function
to bool.  All callers changed.  Do the right thing with
infinities and NaNs.
(time_cmp): New function, which handlesx infinities and NaNs.
(Ftime_less_p): Use it.
(Ftime_equal): New function.
* test/lisp/emacs-lisp/timer-tests.el (timer-test-multiple-of-time):
Use it.

1 files changed, 3 insertions, 5 deletions

diff --git a/test/lisp/emacs-lisp/timer-tests.el b/test/lisp/emacs-lisp/timer-tests.el
index 1d3ba757f63..0e40cdf442f 100644
--- a/test/lisp/emacs-lisp/timer-tests.el
+++ b/test/lisp/emacs-lisp/timer-tests.el
@@ -40,10 +40,8 @@
       (should (debug-timer-check)) t))
 
 (ert-deftest timer-test-multiple-of-time ()
-  (should (zerop
-           (float-time
-            (time-subtract
-             (timer-next-integral-multiple-of-time '(0 0 0 1) (1+ (ash 1 53)))
-             (list (ash 1 (- 53 16)) 1))))))
+  (should (time-equal
+           (timer-next-integral-multiple-of-time '(0 0 0 1) (1+ (ash 1 53)))
+           (list (ash 1 (- 53 16)) 1))))
 
 ;;; timer-tests.el ends here