NAME

       Test::MockModule - Override subroutines in a module for unit testing

SYNOPSIS

               use Module::Name;
               use Test::MockModule;

               {
                       my $module = Test::MockModule->new('Module::Name');
                       $module->mock('subroutine', sub { ... });
                       Module::Name::subroutine(@args); # mocked

                       #Same effect, but this will die() if other_subroutine()
                       #doesn't already exist, which is often desirable.
                       $module->redefine('other_subroutine', sub { ... });
               }

               Module::Name::subroutine(@args); # original subroutine

               # Working with objects
               use Foo;
               use Test::MockModule;
               {
                       my $mock = Test::MockModule->new('Foo');
                       $mock->mock(foo => sub { print "Foo!\n"; });

                       my $foo = Foo->new();
                       $foo->foo(); # prints "Foo!\n"
               }

DESCRIPTION

       "Test::MockModule" lets you temporarily redefine subroutines in other packages for the
       purposes of unit testing.

       A "Test::MockModule" object is set up to mock subroutines for a given module. The object
       remembers the original subroutine so it can be easily restored. This happens automatically
       when all MockModule objects for the given module go out of scope, or when you "unmock()"
       the subroutine.

METHODS

       new($package[, %options])
           Returns an object that will mock subroutines in the specified $package.

           If there is no $VERSION defined in $package, the module will be automatically loaded.
           You can override this behaviour by setting the "no_auto" option:

                   my $mock = Test::MockModule->new('Module::Name', no_auto => 1);

       get_package()
           Returns the target package name for the mocked subroutines

       is_mocked($subroutine)
           Returns a boolean value indicating whether or not the subroutine is currently mocked

       mock($subroutine => \&coderef)
           Temporarily replaces one or more subroutines in the mocked module. A subroutine can be
           mocked with a code reference or a scalar. A scalar will be recast as a subroutine that
           returns the scalar.

           The following statements are equivalent:

                   $module->mock(purge => 'purged');
                   $module->mock(purge => sub { return 'purged'});

           When dealing with references, things behave slightly differently. The following
           statements are NOT equivalent:

                   # Returns the same arrayref each time, with the localtime() at time of mocking
                   $module->mock(updated => [localtime()]);
                   # Returns a new arrayref each time, with up-to-date localtime() value
                   $module->mock(updated => sub { return [localtime()]});

           The following statements are in fact equivalent:

                   my $array_ref = [localtime()]
                   $module->mock(updated => $array_ref)
                   $module->mock(updated => sub { return $array_ref });

           However, "undef" is a special case. If you mock a subroutine with "undef" it will
           install an empty subroutine

                   $module->mock(purge => undef);
                   $module->mock(purge => sub { });

           rather than a subroutine that returns "undef":

                   $module->mock(purge => sub { undef });

           You can call "mock()" for the same subroutine many times, but when you call
           "unmock()", the original subroutine is restored (not the last mocked instance).

           MOCKING + EXPORT

           If you are trying to mock a subroutine exported from another module, this may not
           behave as you initialy would expect, since Test::MockModule is only mocking at the
           target module, not anything importing that module. If you mock the local package, or
           use a fully qualified function name, you will get the behavior you desire:

                   use Test::MockModule;
                   use Test::More;
                   use POSIX qw/strftime/;

                   my $posix = Test::MockModule->new("POSIX");

                   $posix->mock("strftime", "Yesterday");
                   is strftime("%D", localtime(time)), "Yesterday", "`strftime` was mocked successfully"; # Fails
                   is POSIX::strftime("%D", localtime(time)), "Yesterday", "`strftime` was mocked successfully"; # Succeeds

                   my $main = Test::MockModule->new("main", no_auto => 1);
                   $main->mock("strftime", "today");
                   is strftime("%D", localtime(time)), "today", "`strftime` was mocked successfully"; # Succeeds

           If you are trying to mock a subroutine that was exported into a module that you're
           trying to test, rather than mocking the subroutine in its originating module, you can
           instead mock it in the module you are testing:

                   package MyModule;
                   use POSIX qw/strftime/;

                   sub minus_twentyfour
                   {
                           return strftime("%a, %b %d, %Y", localtime(time - 86400));
                   }

                   package main;
                   use Test::More;
                   use Test::MockModule;

                   my $posix = Test::MockModule->new("POSIX");
                   $posix->mock("strftime", "Yesterday");

                   is MyModule::minus_twentyfour(), "Yesterday", "`minus-tewntyfour` got mocked"; # fails

                   my $mymodule = Test::MockModule->new("MyModule", no_auto => 1);
                   $mymodule->mock("strftime", "Yesterday");
                   is MyModule::minus_twentyfour(), "Yesterday", "`minus-tewntyfour` got mocked"; # suceeds

       redefine($subroutine)
           The same behavior as "mock()", but this will preemptively check to be sure that all
           passed subroutines actually exist. This is useful to ensure that if a mocked module's
           interface changes the test doesn't just keep on testing a code path that no longer
           behaves consistently with the mocked behavior.

       original($subroutine)
           Returns the original (unmocked) subroutine

       unmock($subroutine [, ...])
           Restores the original $subroutine. You can specify a list of subroutines to "unmock()"
           in one go.

       unmock_all()
           Restores all the subroutines in the package that were mocked. This is automatically
           called when all "Test::MockObject" objects for the given package go out of scope.

       noop($subroutine [, ...])
           Given a list of subroutine names, mocks each of them with a no-op subroutine. Handy
           for mocking methods you want to ignore!

               # Neuter a list of methods in one go
               $module->noop('purge', 'updated');

SEE ALSO

       Test::MockObject::Extends

       Sub::Override

AUTHORS

       Current Maintainer: Geoff Franks <gfranks@cpan.org>

       Original Author: Simon Flack <simonflk _AT_ cpan.org>

COPYRIGHT

       Copyright 2004 Simon Flack <simonflk _AT_ cpan.org>.  All rights reserved

       You may distribute under the terms of either the GNU General Public License or the
       Artistic License, as specified in the Perl README file.