Test::Builder::Mock::Class - Simulating other classes for Test::Builder


  use Test::Builder::Mock::Class ':all';
  use Test::More 'no_plan';

  # concrete mock class
  mock_class 'Net::FTP' => 'Net::FTP::Mock';
  my $mock_object1 = Net::FTP::Mock->new;

  # anonymous mocked class
  my $metamock2 = mock_anon_class 'Net::FTP';
  my $mock_object2 = $metamock2->new_object;

  # anonymous class with role applied
  my $metamock3 = Test::Builder::Mock::Class->create_mock_anon_class(
      class => 'Net::FTP',
      roles => [ 'My::Handler::Role' ],
  my $mock_object3 = $metamock3->new_object;


This module adds support for standard Test::Builder framework (Test::Simple or Test::More) to Test::Mock::Class.

Mock class can be used to create mock objects which can simulate the behavior of complex, real (non-mock) objects and are therefore useful when a real object is impractical or impossible to incorporate into a unit test.

See Test::Mock::Class for more detailed documentation.



mock_class( class : Str, mock_class : Str = undef ) : Moose::Meta::Class

Creates the concrete mock class based on original class. If the name of mock_class is undefined, its name is created based on name of original class with added ::Mock suffix.

The function returns the metaclass object of new mock_class.

mock_anon_class( class : Str = undef ) : Moose::Meta::Class

Creates an anonymous mock class based on original class. The name of this class is automatically generated. If class argument not defined, the empty mock class is created.

The function returns the metaobject of new mock class.


Test::Builder::Mock::Class ':all';

Imports all functions into caller's namespace.


The Test::Builder::Mock::Class fits perfectly to Test::Builder (Test::Simple or Test::More) tests. It adds automatically the tests for each mock_invoke (which is called implicitly by all mock methods) and mock_tally. It means that you need to add these tests to your test plan.

Example code:

  package My::ExampleTest;

  use Test::More 'no_plan';
  use Test::Builder::Mock::Class ':all';

  require 'IO::File';
  my $mock = mock_anon_class 'IO::File';
  my $io = $mock->new_object;
  $io->mock_return( open => 1, args => [qr//, 'r'] );

  ok( $io->open('/etc/passwd', 'r'), '$io->open' );


Moose after version 1.05 calls BUILDALL method automatically, so this is one more test to whole plan.

Test::More needs an exact count of all tests and it will be different for Moose before and after version 1.05. There are following workarounds:

  # No plan at all
  use Test::More 'no_plan';

  # Different plans depend on Moose version
  use Test::More;
  require Moose;
  plan tests => (Moose->VERSION >= 1.05 ? 10 : 8);

  # Require Moose >= 1.05
  use Moose 1.05 ();
  use Test::More tests => 10;


Mock metaclass API: Test::Builder::Mock::Class::Role::Meta::Class, Moose::Meta::Class.

Mock object methods: Test::Builder::Mock::Class::Role::Object.

Perl standard testing: Test::Builder, Test::Simple, Test::More.

Mock classes for xUnit-like testing (Test::Unit::Lite): Test::Mock::Class.

Other implementations: Test::MockObject, Test::MockClass.


The API is not stable yet and can be changed in future.


Piotr Roszatycki <>


Based on SimpleTest, an open source unit test framework for the PHP programming language, created by Marcus Baker, Jason Sweat, Travis Swicegood, Perrick Penet and Edward Z. Yang.

Copyright (c) 2009, 2010 Piotr Roszatycki <>.

This program is free software; you can redistribute it and/or modify it under GNU Lesser General Public License.