Test::MockTime(3)

NAME
Test::MockTime - Replaces actual time with simulated time

VERSION
Version 0.17

SYNOPSIS
  use Test::MockTime qw( :all );
  set_relative_time(-600);

  # do some tests depending on time increasing from 600 seconds ago

  set_absolute_time(0);

  # do some more tests depending on time starting from the epoch
  # epoch may vary according to platform.  see perlport.

  set_fixed_time(CORE::time());

  # do some more tests depending on time staying at the current actual time

  set_absolute_time('1970-01-01T00:00:00Z');

  # do some tests depending on time starting at Unix epoch time

  set_fixed_time('01/01/1970 00:00:00', '%m/%d/%Y %H:%M:%S');

  # do some tests depending on time staying at the Unix epoch time

  restore_time();

  # resume normal service

DESCRIPTION
This module was created to enable test suites to test code at specific points in time. Specifically it overrides localtime, gmtime and time at compile time and then relies on the user supplying a mock time via set_relative_time, set_absolute_time or set_fixed_time to alter future calls to gmtime,time or localtime.

SUBROUTINES/METHODS

set_absolute_time
    If given a single, numeric argument, the argument is an absolute time (for example, if 0 is supplied, the absolute time will be the epoch), and calculates the offset to allow subsequent calls to time, gmtime and localtime to reflect this.

    for example, in the following code

      Test::MockTime::set_absolute_time(0);
      my ($start) = time;
      sleep 2;
      my ($end) = time;

    The $end variable should contain 2 seconds past the epoch;

    If given two arguments, the first argument is taken to be an absolute time in some string format (for example, "01/01/1970 00:00:00"). The second argument is taken to be a "strptime" format string (for example, "%m/%d/%Y %H:%M:%S"). If a single argument is given, but that argument is not numeric, a "strptime" format string of "%Y-%m-%dT%H:%M:%SZ" is assumed.

    for example, in the following code

      Test::MockTime::set_absolute_time('1970-01-01T00:00:00Z');
      my ($start) = time;
      sleep 2;
      my ($end) = time;

    The $end variable should contain 2 seconds past the Unix epoch;

set_relative_time($relative)
    takes as an argument an relative value from current time (for example, if -10 is supplied, current time be converted to actual machine time - 10 seconds) and calculates the offset to allow subsequent calls to time,gmtime and localtime to reflect this.

    for example, in the following code

      my ($start) = time;
      Test::MockTime::set_relative_time(-600);
      sleep 600;
      my ($end) = time;

    The $end variable should contain either the same or very similar values to the $start variable.

set_fixed_time
    If given a single, numeric argument, the argument is an absolute time (for example, if 0 is supplied, the absolute time will be the epoch). All subsequent calls to gmtime, localtime and time will return this value.

    for example, in the following code

      Test::MockTime::set_fixed_time(time)
      my ($start) = time;
      sleep 3;
      my ($end) = time;

    the $end variable and the $start variable will contain the same results

    If given two arguments, the first argument is taken to be an absolute time in some string format (for example, "01/01/1970 00:00:00"). The second argument is taken to be a "strptime" format string (for example, "%m/%d/%Y %H:%M:%S"). If a single argument is given, but that argument is not numeric, a "strptime" format string of "%Y-%m-%dT%H:%M:%SZ" is assumed.

restore()
    restore the default time handling values. "restore_time" is an alias. When exported with the 'all' tag, this subroutine is exported as "restore_time".

CONFIGURATION AND ENVIRONMENT
Test::MockTime requires no configuration files or environment variables.

DEPENDENCIES
Test::MockTime depends on the following non-core Perl modules.

•   Time::Piece 1.08 or greater

INCOMPATIBILITIES
None reported

BUGS AND LIMITATIONS
Probably.

AUTHOR
David Dick <ddick@cpan.org>

LICENSE AND COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

ACKNOWLEDGEMENTS
Thanks to a use.perl.org journal entry <http://use.perl.org/~geoff/journal/20660> by Geoffrey Young.