++ed by:
Author image Ben Marcotte
and 3 contributors


Test::Subtest::Attribute - Declare subtests using subroutine attributes


version 0.04


  use Test::More;
  use Test::Subtest::Attribute qw( subtests );

  sub subtest_foo :Subtest {
      ok( 1, 'foo is OK' );
      return 1;

  sub subtest_bar :Subtest( 'name for bar' ) {
      ok( 1, 'bar is OK' );
      return 1;



This module provides a simple way, using a subroutine attribute called :Subtest, to declare normal subroutines to be subtests in a test script.

Subtests are typically declared using a call to the subtest() function from Test::More, in one of the two following ways:

  subtest 'name1'  => sub { ... };  # An anonymous sub
  subtest 'name 2' => \&some_named_sub;

The first way can quickly lead to long anonymous subs that can present issues when looking at stacktraces for debugging, profiling, logging, etc. The second way usually leads to repeating the same, or similar, names for each subtest subroutine, in addition to declaring the sub itself, e.g.:

  subtest 'test_this' => \&test_this;
  subtest 'test_that' => \&test_that;
  sub test_this { ... }
  sub test_that { ... }

This module lets you declare those subtests without calls to the subtest() function, by simply adding a :Subtest attribute to any subroutine that you'd like to have executed as a subtest, like so:

  sub subtest_name1 :Subtest {

That declares a subtest named 'name1' (the subtest_ part of the name, if present, is automatically stripped off).

If you'd like to specify the name of the subtest explicitly, which is handy if you'd like to use a name that includes characters. such as spaces, that aren't allowed in bareword identifiers, you can do so by providing an argument to the :Subtest attribute like so:

  sub some_named_sub :Subtest('name 2') {

When you're done declaring subtests, you run all the ones you've queued up by calling subtests()-run()>.

From this module, most test scripts will only need to use the :Subtest attribute and the run() method described below. Most of the other methods described below are for more advanced usage, such as in test modules that might want to conditionally add, remove, or otherwise manipulate the subtests managed herein.



  subtests()->add( coderef => \%my_sub );

Adds a subroutine to the current queue of subtests. This method can accept a number of named arguments.


Indicates the name of this particular subtest. If the name isn't unique, it will replace the previously declared subtest with the same name.


A value of 'prepend' indicates the subtest should be added to the head of the queue of subtests. A value of 'append' indicates the subtest should be added to the end of the queue of subtests. If not given, the default is to append the subtest.


A reference to the subroutine (named or anonymous) to eventually call for this subtest.


The package from which the subtest should be invoked. Typically, this would be the package that the subroutine lives in. Calling the run() method with an invocant argument takes precedence over this. It also appears in the fully qualified subroutine name, if run() is called in verbose mode. Defaults to main if not given.


The name of the subroutine to call for this subtest. If coderef is defined, this is only needed for display purposes. If coderef is not defined, the run() method will attempt to find a sub with this name that can be called via the invocant or package arguments.


  subtests()->prepend( coderef => \%my_sub );

Adds a subtest to the head of the current queue of subtests. Takes the same arguments as the add() method, and sets the where param to prepend.


  subtests()->append( coderef => \%my_sub );

Adds a subtest to the end of the current queue of subtests. Takes the same arguments as the add() method, and sets the where param to append.


  subtests()->remove( $name_or_coderef );

Removes the indicated subtest(s) from the queue. The argument can either be the name or the coderef associated with the subtest.



Returns a list of all of the subtests currently in the queue.


  subtests()->run( %args );

Runs all of the subtests that are currently in the queue.

This method can be called with any of the following arguments:


The test builder to use. If none is given, a new Test::Builder instance will be created.


If given, the subtest subroutines will be invoked via this reference.

NOTE: When the :Subtest attribute is used, the name of the package that the subroutine appears in will be remembered in the subtest metadata, and that package name will be used if no invocant argument is given explicitly when calling this method. If that value happens to be undefined for any reason, the package name main is the default instead.


When given, and set to a true value, subtest names will be displayed with [sub name] appended. If the package name can be determined, and is not main, the sub name will be fully qualified with such.



Returns a handle that can be used to invoke the methods in this module. As such, this is the only function exported by this module.

Currently, this just returns the name of this package, but, in the future, it could return an object instance.


Attribute::Handlers Test::Builder


Ben Marcotte <bmarcotte NOSPAM cpan.org>


This software is copyright (c) 2017 by Ben Marcotte.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.