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.

