Fix 'timer-next-integral-multiple-of-time'

* lisp/emacs-lisp/timer.el
(timer-next-integral-multiple-of-time): Fix recent change for
fractional values of SECS.  (Bug#33071)
* test/lisp/emacs-lisp/timer-tests.el
(timer-next-integral-multiple-of-time-2): New test.

2 files changed, 9 insertions, 1 deletions

diff --git a/lisp/emacs-lisp/timer.el b/lisp/emacs-lisp/timer.el
index 927e640feaa..e140738d9f3 100644
--- a/lisp/emacs-lisp/timer.el
+++ b/lisp/emacs-lisp/timer.el
@@ -101,7 +101,7 @@ of SECS seconds since the epoch.  SECS may be a fraction."
                        time
                      (encode-time time 1000000000000)))
          (hz (cdr ticks-hz))
-         (s-ticks (* secs hz))
+         (s-ticks (round (* secs hz)))
          (more-ticks (+ (car ticks-hz) s-ticks)))
     (encode-time (cons (- more-ticks (% more-ticks s-ticks)) hz))))
 
diff --git a/test/lisp/emacs-lisp/timer-tests.el b/test/lisp/emacs-lisp/timer-tests.el
index c5971ee7687..7a5b9263b0b 100644
--- a/test/lisp/emacs-lisp/timer-tests.el
+++ b/test/lisp/emacs-lisp/timer-tests.el
@@ -44,4 +44,12 @@
            (timer-next-integral-multiple-of-time '(0 0 0 1) (1+ (ash 1 53)))
            (list (ash 1 (- 53 16)) 1))))
 
+(ert-deftest timer-next-integral-multiple-of-time-2 ()
+  "Test bug#33071."
+  (let* ((tc (current-time))
+         (tce (encode-time tc 100))
+         (nt (timer-next-integral-multiple-of-time tc 0.01))
+         (nte (encode-time nt 100)))
+    (should (= (car nte) (1+ (car tce))))))
+
 ;;; timer-tests.el ends here