fix: harden t/gh10.t skip logic and update stale docs

lib/Date/Format.pm

@@ -173,9 +173,10 @@ with C<O>, e.g. C<%OY> will output the year as roman numerals.
 
 =head1 LIMITATION
 
-The functions in this module are limited to the time range that can be
-represented by the time_t data type, i.e. 1901-12-13 20:45:53 GMT to
-2038-01-19 03:14:07 GMT.
+On Perl 5.12 and later with a 64-bit integer (the common case on modern
+systems), dates far beyond 2038 are supported.  On older 32-bit builds of
+Perl, the functions in this module are limited to the range of the
+C<time_t> data type: 1901-12-13 20:45:53 GMT to 2038-01-19 03:14:07 GMT.
 
 =head1 AUTHOR
 

lib/Date/Parse.pm

@@ -472,6 +472,17 @@ Below is a sample list of dates that are known to be parsable with Date::Parse
  1999 10:02:18 "GMT"
  16 Nov 94 22:28:20 PST
 
+=head1 MISSING YEAR INFERENCE
+
+When the input date string does not contain a year, C<str2time> assumes the
+date refers to the most recent past occurrence.  If the month (and day) have
+not yet occurred in the current year, the previous year is used.  For example,
+parsing C<"25 Dec"> in June will return December 25 of the previous year, while
+parsing C<"15 Mar"> in June will return March 15 of the current year.
+
+The reference time used for this inference defaults to C<time()> but can be
+overridden with the optional C<EPOCH> parameter.
+
 =head1 BUGS
 
 When both the month and the date are specified in the date as numbers

t/gh10.t

@@ -27,15 +27,18 @@ BEGIN {
 
 use POSIX qw();
 use Test::More;
+use Time::Zone qw();
 use Date::Format qw(time2str);
 
 # Skip the whole file if the platform does not support IANA timezone names.
-# Use epoch 1352019262 (2012-11-04 01:04:22 PDT): DST=1 in America/Los_Angeles
-# but DST=0 in UTC, so this check actually distinguishes the two and won't
-# produce a false-positive on a UTC-only system.
+# We verify that TZ='America/Los_Angeles' actually took effect by checking
+# both the DST flag AND the UTC offset for a known PDT epoch.  Checking only
+# the DST flag can false-positive on systems where TZ assignment fails but
+# the host's native timezone happens to have DST at this epoch (GH#99).
 my $has_la_tz = eval {
     my @lt = localtime(1352019262);    # 2012-11-04 01:04:22 PDT (before fall-back)
-    $lt[8] == 1;                       # Expect DST flag = 1 in PDT
+    $lt[8] == 1                        # Expect DST flag = 1 in PDT
+    && Time::Zone::calc_off(1352019262) == -7*3600;  # Expect UTC-7 (PDT offset)
 };
 plan( skip_all => "system does not support America/Los_Angeles timezone" )
     unless $has_la_tz;