Don’t stress-test time zones near the Epoch

* test/src/editfns-tests.el (format-time-string-with-zone)
(format-time-string-with-outlandish-zone): Don’t format
timestamps near the Epoch, as this runs into bugs on MS-Windows,
and we don’t want to worry about those bugs.
This commit is contained in:
Paul Eggert 2017-05-01 10:41:50 -07:00
parent 6f0dfad84e
commit a4dc24cf4f

View file

@ -140,21 +140,38 @@
;;; Use only POSIX-compatible TZ values, since the tests should work
;;; even if tzdb is not in use.
(ert-deftest format-time-string-with-zone ()
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S %z" '(0 0 0 0) t)
"1970-01-01 00:00:00 +0000"))
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S %z (%Z)" '(0 0 0 0) "PST8")
"1969-12-31 16:00:00 -0800 (PST)"))
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S %z (%Z)" '(0 0 0 0)
"NZST-12NZDT,M9.5.0,M4.1.0/3")
"1970-01-01 13:00:00 +1300 (NZDT)")))
;; Dont use (0 0 0 0) as the test case, as there are too many bugs
;; in MSVC (and presumably other) C libraries when formatting time
;; stamps near the Epoch of 1970-01-01 00:00:00 UTC, and this test
;; is for GNU Emacs, not for C runtimes. Instead, look before you
;; leap: "look" is the timestamp just before the first leap second
;; on 1972-06-30 23:59:60 UTC, so it should format to the same
;; string regardless of whether the underlying C library ignores
;; leap seconds, while avoiding circa-1970 glitches.
(let ((look '(1202 22527 999999 999999)))
;; UTC.
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S.%3N %z" look t)
"1972-06-30 23:59:59.999 +0000"))
;; Time zone without DST in 1972.
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S.%3N %z (%Z)" look "NZST-12")
"1972-07-01 11:59:59.999 +1200 (NZST)"))
;; United States DST in 1972.
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S.%3N %z (%Z)" look
"PST8PDT,M4.5.0,M10.5,0")
"1972-06-30 16:59:59.999 -0700 (PDT)"))
;; New South Wales DST in 1971-2.
(should (string-equal
(format-time-string "%Y-%m-%d %H:%M:%S.%3N %z (%Z)" look
"AEST-10AEDT,M10.5.0,M2.5.0/3")
"1972-07-01 09:59:59.999 +1000 (AEST)"))))
;;; This should not dump core.
(ert-deftest format-time-string-with-outlandish-zone ()
(should (stringp
(format-time-string "%Y-%m-%d %H:%M:%S %z" '(0 0 0 0)
(format-time-string "%Y-%m-%d %H:%M:%S.%3N %z" nil
(concat (make-string 2048 ?X) "0")))))
;;; editfns-tests.el ends here