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NAME

Class::Mockable


DESCRIPTION

A handy mix-in for making stuff mockable.

Use this so that when testing your code you can easily mock how your code talks to other bits of code, thus making it possible to test your code in isolation, and without relying on third-party services.


SYNOPSIS

    use Class::Mockable
        _email_sender         => 'Email::Sender::Simple',
        _email_sent_storage   => 'MyApp::Storage::EmailSent';

is equivalent to:

    {
        my $email_sender;
        _reset_email_sender();
        sub _reset_email_sender {
            $email_sender = 'Email::Sender::Simple'
        };
        sub _email_sender {
            my $class = shift;
            if (exists($_[0])) { $email_sender = shift; }
            return $email_sender;
        }
        my $email_sent_storage;
        _reset_email_sent_storage();
        sub _reset_email_sent_storage {
            $email_sent_storage = 'MyApp::Storage::EmailSent'
        };
        sub _email_sent_storage {
            my $class = shift;
            if (exists($_[0])) { $email_sent_storage = shift; }
            return $email_sent_storage;
        }
    }


HOW TO USE IT

After setting up as above, the anywhere that your code would want to refer to the class 'Email::Sender::Simple', for example, you would do this:

    my $sender = $self->_email_sender();

In your tests, you would do this:

    My::Module->_email_sender('MyApp::Tests::Mocks::EmailSender');
    ok(My::Module->send_email(...), "email sending stuff works");

where 'MyApp::Tests::Mocks::EmailSender' pretends to be the real email sending class, only without spamming everyone every time you run the tests. And of course, if you do want to really send email from a test - perhaps you want to do an end-to-end test before releasing - you would do this:

    My::Module->_reset_email_sender() if($ENV{RELEASE_TESTING});
    ok(My::Module->send_email(...),
        "email sending stuff works (without mocking)");

to restore the default functionality.

METHOD MOCKING

We also provide a way of easily inserting shims that wrap around methods that you have defined.

    use Class::Mockable
        methods => {
            _foo => 'foo',
        };

The above will create a _foo sub on your class that by default will call your class's foo() subroutine. This behaviour can be changed by calling the setter function _set_foo (where _foo is your identifier). The default behaviour can be restored by calling _reset_foo (again, where _foo is your identifier).

For example:

    package Some::Module;
    use Class::Mockable
        methods => {
            _bar => 'bar',
        };
    sub bar {
        my $self = shift;
        return "Bar";
    }
    sub foo {
        my $self = shift;
        return $self->_bar();
    }
    package main;
    Some::Module->_set_bar(
        sub {
            my $self = shift;
            return "Foo";
        }
    );
    print Some::Module->bar();         # Prints "Bar"
    print Some::Module->foo();         # Prints "Foo"
    Some::Module->_reset_bar();
    print Some::Module->bar();         # Prints "Bar"
    print Some::Module->foo();         # Prints "Bar"

It will also work for inserting a shim into a subclass to wrap around a method inherited from a superclass.


CAVEATS

If you use namespace::autoclean in the same module as this it may ``helpfully'' delete mocked methods that you create. You may need to explicitly exclude those from namespace::autoclean's list of things to clean.


AUTHOR

Copyright 2012-13 UK2 Ltd and David Cantrell <david@cantrell.org.uk>

With some bits from James Ronan

This software is free-as-in-speech software, and may be used, distributed, and modified under the terms of either the GNU General Public Licence version 2 or the Artistic Licence. It's up to you which one you use. The full text of the licences can be found in the files GPL2.txt and ARTISTIC.txt, respectively.


SOURCE CODE REPOSITORY

<git://github.com/DrHyde/perl-modules-Class-Mockable.git>


BUGS/FEEDBACK

Please report bugs at Github <https://github.com/DrHyde/perl-modules-Class-Mockable/issues>


CONSPIRACY

This software is also free-as-in-mason.