# Test::MockTime - Replaces actual time with simulated time - perldoc - [phpMan]

## NAME
    [Test::MockTime](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime/markdown) - Replaces actual time with simulated time

## VERSION
    Version 0.17

## SYNOPSIS
      use [Test::MockTime](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime/markdown) qw( :all );
      set_relative_time(-600);

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

      [set_absolute_time(0)](https://www.chedong.com/phpMan.php/man/setabsolutetime/0/markdown);

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

      set_fixed_time([CORE::time](https://www.chedong.com/phpMan.php/perldoc/CORE%3A%3Atime/markdown)());

      # 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](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime/markdown)::[set_absolute_time(0)](https://www.chedong.com/phpMan.php/man/setabsolutetime/0/markdown);
          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](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime%3A%3Asetabsolutetime/markdown)('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
        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 ($start) = time;
          [Test::MockTime::set_relative_time](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime%3A%3Asetrelativetime/markdown)(-600);
          sleep 600;
          my ($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](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime%3A%3Asetfixedtime/markdown)(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](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime/markdown) requires no configuration files or environment variables.

## DEPENDENCIES
    [Test::MockTime](https://www.chedong.com/phpMan.php/perldoc/Test%3A%3AMockTime/markdown) depends on the following non-core Perl modules.

    *   [Time::Piece](https://www.chedong.com/phpMan.php/perldoc/Time%3A%3APiece/markdown) 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.