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| author | Paul Eggert <eggert@cs.ucla.edu> | 2019-08-16 16:25:02 -0700 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2019-08-16 16:27:27 -0700 |
| commit | f9fd12a30b3d94eb48f7b309907d136d7b2682ac (patch) | |
| tree | d00aa93beec6eb1013127ee251342f39f135a994 /test/lisp/timezone-tests.el | |
| parent | e82923c817159c751aa9c902093a46b9457e8499 (diff) | |
| download | emacs-f9fd12a30b3d94eb48f7b309907d136d7b2682ac.tar.gz emacs-f9fd12a30b3d94eb48f7b309907d136d7b2682ac.tar.bz2 emacs-f9fd12a30b3d94eb48f7b309907d136d7b2682ac.zip | |
Fix time-add rounding bug
Without this fix, time arithmetic yielded results that were not
mathematically accurate, even though the exact results were
representable; for example, (time-add 0 1e-13) yielded a timestamp
equal to 0 instead of to 1e-13.
* lisp/timezone.el (timezone-time-from-absolute):
Let time-add do its thing rather than using floating point
internally, which has rounding errors. We now have bignums and so
don’t need floating point to avoid overflow issues.
* src/timefns.c (timeform_sub_ps_p): New function.
(time_arith): If either argument is a float, represent the
result exactly instead of discarding sub-ps info.
* test/lisp/timezone-tests.el (timezone-tests-time-from-absolute):
Don’t assume (HI LO US PS) timestamp format.
* test/src/emacs-module-tests.el (mod-test-add-nanosecond/valid):
Don’t assume that time-add discards sub-ns info.
* test/src/timefns-tests.el (time-rounding-tests):
Add regression test to detect time-add rounding bug.
Diffstat (limited to 'test/lisp/timezone-tests.el')
| -rw-r--r-- | test/lisp/timezone-tests.el | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/test/lisp/timezone-tests.el b/test/lisp/timezone-tests.el index 4b5f5617ecd..c374042fa5d 100644 --- a/test/lisp/timezone-tests.el +++ b/test/lisp/timezone-tests.el @@ -135,9 +135,10 @@ (should (equal (timezone-zone-to-minute "*invalid*") 0))) (ert-deftest timezone-tests-time-from-absolute () - (should (equal (timezone-time-from-absolute (* 2020 365) ; Jan 1 2020 - (* 12 60 60)) ; 12:00 - '(23911 48704 0 0)))) + (should (time-equal-p + (timezone-time-from-absolute (* 2020 365) ; Jan 1 2020 + (* 12 60 60)) ; 12:00 + '(23911 48704 0 0)))) ;; TODO: Write tests for timezone-tests-time-zone-from-absolute, which is a ;; bit tricky since the results depend on `current-time-zone'. |