Test::Signature - Automated SIGNATURE testing


    # This is actually the t/0-signature.t file from this distribution.
    use Test::More tests => 1;
    use Test::Signature;



Test::Signature verifies that the Module::Signature generated signature of a module is correct.


Module::Signature allows you to verify that a distribution has not been tampered with. Test::Signature lets that be tested as part of the distribution's test suite.

By default, if Module::Signature is not installed then it will just say so and not fail the test. That can be overridden though.

IMPORTANT: This is not a substitute for the users verifying the distribution themselves. By the time this module is run, the users will have already run your Makefile.PL or Build.PL scripts which could have been compromised.

This module is more for ensuring you've updated your signature appropriately before distributing, and for preventing accidental errors during transmission or packaging.


signature_ok is exported by default. signature_force_ok must be explicitly exported.


This will test that the Module::Signature generated signature is valid for the distribution. It can be given two optional parameters. The first is a name for the test. The default is Valid signature. The second is whether a lack of Module::Signature should be regarded as a failure. The default is 0 meaning 'no'.

    # Test with defaults
    # Test with custom name
    signature_ok( "Is the signature valid?" );
    # Test with custom name and force C<Module::Signature> to exist
    signature_ok( "Is the signature valid?", 1 );
    # Test without custom name, but forcing
    signature_ok( undef, 1 );


This is equivalent to calling signature_ok( $name, 1 ) but is more readable.

    # These are equivalent:
    signature_force_ok( "Is our signature valid?" );
    signature_ok( "Is our signature valid?", 1);

    # These are equivalent:
    signature_ok( undef, 1 );



It is imperative that your MANIFEST and MANIFEST.SKIP files be accurate and complete. If you are using ExtUtils::MakeMaker and you do not have a MANIFEST.SKIP file, then don't worry about the rest of this. If you do have a MANIFEST.SKIP file, or you use Module::Build, you must read this.

Since the test is run at make test time, the distribution has been made. Thus your MANIFEST.SKIP file should have the entries listed below.

If you're using ExtUtils::MakeMaker, you should have, at least:


These entries are part of the default set provided by ExtUtils::Manifest, which is ignored if you provide your own MANIFEST.SKIP file.

If you are using Module::Build, there is no default MANIFEST.SKIP so you must provide your own. It must, minimally, contain:


If you don't have the correct entries, Module::Signature will complain that you have:

    ==> MISMATCHED content between MANIFEST and distribution files! <==

You should note this during normal development testing anyway.

Use with Test::Prereq

Test::Prereq tends to get a bit particular about modules. If you're using the force option with Test::Signature then you will have to specify that you expect Module::Signature as a prerequisite. Test::Signature will not have it as a prerequisite since that would defeat the point of having the force variant.

If you are using ExtUtils::MakeMaker you should have a line like the following in your Makefile.PL:

    'PREREQ_PM' => {
        'Test::Signature'   => '1.04',
        'Module::Signature' => '0.22',
        'Test::More'        => '0.47',

If using Module::Build, your Build.PL should have:

    build_requires => {
        'Test::Signature'   => '1.04',
        'Module::Signature' => '0.22',
        'Test::More'        => '0.47',

If you just want the default behaviour of testing the signature if and only if the user already has Module::Signature installed, then you will need something like the following code. The example uses Module::Build format but it should be trivial for you to translate to ExtUtils::MakeMaker.

    #!/usr/bin/perl -w
    use strict;
    use Module::Build 0.18;

    my @extra_build;

    eval { require Module::Signature };
    if (!$@ or $Test::Prereq::VERSION)
        push @extra_build, "Module::Signature" => '0.22'

    my $m = Module::Build->new(
        dist_name => 'WWW-Yahoo-Groups',
        dist_version => '1.7.7',
        license => 'perl',

        requires => {
            # various modules
            'perl'             => '5.6.0',
        build_requires => {
            'Test::More'          => 0.47,
            'Test::Prereq'        => 0.19,
            'Test::Prereq::Build' => 0.04,
            'Test::Signature'     => 1.04,


If you have any questions on using this module with Test::Prereq, just email me (address below).

Use with Module::Install

Module::Install is a module to assist in the bundling of build prerequisite modules in packages. Well, among other things.

Test::Signature is a perfect candidate for such a module. As it's a module aimed purely at those writing modules rather than those using them.

Here's a good way to use it:

Make a test file (say, t/00sig.t) that contains the following:

    use lib 'inc';
    use Test::More tests => 1;
    use Test::Signature;

In your Makefile.PL (or Build.PL if appropriate) add:

    include 'Test::Signature';

And that's it! You don't have to specify it as a prerequisite or anything like that because Module::Install will include it in your distribution. And you don't have to worry about size because Module::Install strips out all this waffling POD.


Arthur Bergman for suggesting the module.

Audrey Tang for writing Module::Signature, and making some suggestions.

Tels suggested testing network connectivity to Audrey; Audrey added that to Module::Signature 0.16 and I (Iain Truskett) added it to this module (as of 1.03).


Please report bugs at <> or via the web interface at


Audrey Tang <> Original author: Iain Truskett <>, now passed away.


Copyright 2002, 2003 by Iain Truskett. Copyright 2003, 2007, 2015 by Audrey Tang <>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


perl, Module::Signature, Test::More.

Module::Build, ExtUtils::Manifest, ExtUtils::MakeMaker.

Test::Prereq, Module::Install.