use POSIX       qw( strftime );
use Time::Local qw( timelocal );

# Pretend we're executing at 12:00:05 am on Mar 12th, 2008.
# The DST time zone change occured on Mar 9th, 2008 here.
my $time = timelocal(5,0,0,12,3-1,2008);

my $offset = 7;
my $date = strftime "%Y-%m-%d",
    localtime($time - $offset * 86400);

print("Expecting: 2008-03-05\n");
print("Received:  $date\n");