NAME

   Mock::Sub - Mock module, package, object and standard subroutines, with
   unit testing in mind.

SYNOPSIS

       # see EXAMPLES for a full use case and caveats

       use Mock::Sub;

       my $foo = Mock::Sub->mock('Package::foo');

       # wait until the mocked sub is called

       Package::foo();

       # then...

       $foo->name;         # name of sub that's mocked
       $foo->called;       # was the sub called?
       $foo->called_count; # how many times was it called?
       $foo->called_with;  # array of params sent to sub

       # create a mock object to reduce typing when multiple subs
       # are mocked

       my $mock = Mock::Sub->new;

       my $foo = $mock->mock('Package::foo');
       my $bar = $mock->mock('Package::bar');

       # have the mocked sub return something when it's called (you can use void
       # context if you don't need the functionality of the object)

       $mock->mock('Package::foo', return_value => 'True');
       my $return = Package::foo;

       # have the mocked sub perform an action (void context again)

       $mock->mock('Package::foo', side_effect => sub { die "eval catch"; });
       eval { Package::foo; };
       print 'died' if $@;

       # extract the parameters the sub was called with (best if you know what
       # the original sub is expecting)

       my @args = $foo->called_with;

       # add/change/remove the side_effect after instantiation

       $foo->side_effect(sub {die;});

       # add/change/remove the return_value after instantiation

       $foo->return_value(50);

       # reset the mocked sub for re-use within the same scope

       $foo->reset;

       # restore original functionality to the sub

       $foo->unmock;

DESCRIPTION

   Easy to use and very lightweight module for mocking out sub calls. Very
   useful for testing areas of your own modules where getting coverage may
   be difficult due to nothing to test against, and/or to reduce test run
   time by eliminating the need to call subs that you really don't want or
   need to test.

EXAMPLE

   Here's a full example to get further coverage where it's difficult if
   not impossible to test certain areas of your code (eg: you have if/else
   statements, but they don't do anything but call other subs. You don't
   want to test the subs that are called, nor do you want to add
   statements to your code).

   Note that if the end subroutine you're testing is NOT Object Oriented
   (and you're importing them into your module that you're testing), you
   have to mock them as part of your own namespace (ie. instead of
   Other::first, you'd mock MyModule::first).

      # module you're testing:

       package MyPackage;

       use Other;
       use Exporter qw(import);
       @EXPORT_OK = qw(test);

       my $other = Other->new;

       sub test {
           my $arg = shift;

           if ($arg == 1){
               # how do you test this... there's no return etc.
               $other->first();
           }
           if ($arg == 2){
               $other->second();
           }
       }

       # your test file

       use MyPackage qw(test);
       use Mock::Sub;
       use Test::More tests => 2;

       my $mock = Mock::Sub->new;

       my $first = $mock->mock('Other::first');
       my $second = $mock->mock('Other::second');

       # coverage for first if() in MyPackage::test
       test(1);
       is ($first->called, 1, "1st if() statement covered");

       # coverage for second if()
       test(2);
       is ($second->called, 1, "2nd if() statement covered");

METHODS

new

   Instantiates and returns a new Mock::Sub object.

mock('sub', %opts)

   Instantiates a new object on each call. 'sub' is the name of the
   subroutine to mock (requires full package name if the sub isn't in
   main::).

   Options:

   return_value

     Set this to have the mocked sub return anything you wish.

   side_effect

     Send in a code reference containing an action you'd like the mocked
     sub to perform (die() is useful for testing with eval()).

     You can use both side_effect and return_value params at the same
     time. side_effect will be run first, and then return_value. Note that
     if side_effect's last expression evaluates to any value whatsoever
     (even false), it will return that and return_value will be skipped.

     To work around this and have the side_effect run but still get the
     return_value thereafter, write your cref to evaluate undef as the
     last thing it does: sub {...; undef; }.

unmock

   Restores the original functionality back to the sub, and runs reset()
   on the object.

called

   Returns true if the sub being mocked has been called.

called_count

   Returns the number of times the mocked sub has been called.

called_with

   Returns an array of the parameters sent to the subroutine.

name

   Returns the full name of the sub being mocked, as entered into mock().

side_effect($cref)

   Add (or remove) a side effect after instantiation. Same rules apply
   here as they do for the side_effect parameter.

return_value

   Add (or change, delete) the mocked sub's return value after
   instantiation. Takes a single parameter, which can be anything you want
   it to be. Send in undef to remove a previously set value.

reset

   Resets the functional parameters (return_value, side_effect), along
   with called() and called_count() back to undef/false.

NOTES

   I didn't make this a Test:: module (although it started that way)
   because I can see more uses than placing it into that category.

AUTHOR

   Steve Bertrand, <steveb at cpan.org>

BUGS

   Please report any bugs or requests at
   https://github.com/stevieb9/mock-sub/issues

REPOSITORY

   https://github.com/stevieb9/mock-sub

BUILD RESULTS

   Travis-CI: https://travis-ci.org/stevieb9/mock-sub

   CPAN Testers: http://matrix.cpantesters.org/?dist=Mock-Sub

SUPPORT

   You can find documentation for this module with the perldoc command.

       perldoc Mock::Sub

ACKNOWLEDGEMENTS

   Python's MagicMock module.

LICENSE AND COPYRIGHT

   Copyright 2015 Steve Bertrand.

   This program is free software; you can redistribute it and/or modify it
   under the terms of either: the GNU General Public License as published
   by the Free Software Foundation; or the Artistic License.

   See http://dev.perl.org/licenses/ for more information.