[patch @13687] Unicode::Collate 0.10

[p5sagit/p5-mst-13.2.git] / lib / Test / More.pm

package Test::More;

use 5.004;

use strict;
use Test::Builder;


# Can't use Carp because it might cause use_ok() to accidentally succeed
# even though the module being used forgot to use Carp.  Yes, this
# actually happened.
sub _carp {
    my($file, $line) = (caller(1))[1,2];
    warn @_, sprintf " at $file line $line\n";
}



require Exporter;
use vars qw($VERSION @ISA @EXPORT %EXPORT_TAGS $TODO);
$VERSION = '0.33';
@ISA    = qw(Exporter);
@EXPORT = qw(ok use_ok require_ok
             is isnt like is_deeply
             skip todo
             pass fail
             eq_array eq_hash eq_set
             $TODO
             plan
             can_ok  isa_ok
            );

my $Test = Test::Builder->new;


# 5.004's Exporter doesn't have export_to_level.
sub _export_to_level
{
      my $pkg = shift;
      my $level = shift;
      (undef) = shift;                  # XXX redundant arg
      my $callpkg = caller($level);
      $pkg->export($callpkg, @_);
}


=head1 NAME

Test::More - yet another framework for writing test scripts

=head1 SYNOPSIS

  use Test::More tests => $Num_Tests;
  # or
  use Test::More qw(no_plan);
  # or
  use Test::More skip_all => $reason;

  BEGIN { use_ok( 'Some::Module' ); }
  require_ok( 'Some::Module' );

  # Various ways to say "ok"
  ok($this eq $that, $test_name);

  is  ($this, $that,    $test_name);
  isnt($this, $that,    $test_name);
  like($this, qr/that/, $test_name);

  is_deeply($complex_structure1, $complex_structure2, $test_name);

  SKIP: {
      skip $why, $how_many unless $have_some_feature;

      ok( foo(),       $test_name );
      is( foo(42), 23, $test_name );
  };

  TODO: {
      local $TODO = $why;

      ok( foo(),       $test_name );
      is( foo(42), 23, $test_name );
  };

  can_ok($module, @methods);
  isa_ok($object, $class);

  pass($test_name);
  fail($test_name);

  # Utility comparison functions.
  eq_array(\@this, \@that);
  eq_hash(\%this, \%that);
  eq_set(\@this, \@that);

  # UNIMPLEMENTED!!!
  my @status = Test::More::status;

  # UNIMPLEMENTED!!!
  BAIL_OUT($why);


=head1 DESCRIPTION

If you're just getting started writing tests, have a look at
Test::Simple first.  This is a drop in replacement for Test::Simple
which you can switch to once you get the hang of basic testing.

This module provides a very wide range of testing utilities.  Various
ways to say "ok", facilities to skip tests, test future features
and compare complicated data structures.


=head2 I love it when a plan comes together

Before anything else, you need a testing plan.  This basically declares
how many tests your script is going to run to protect against premature
failure.

The preferred way to do this is to declare a plan when you C<use Test::More>.

  use Test::More tests => $Num_Tests;

There are rare cases when you will not know beforehand how many tests
your script is going to run.  In this case, you can declare that you
have no plan.  (Try to avoid using this as it weakens your test.)

  use Test::More qw(no_plan);

In some cases, you'll want to completely skip an entire testing script.

  use Test::More skip_all => $skip_reason;

Your script will declare a skip with the reason why you skipped and
exit immediately with a zero (success).  See L<Test::Harness> for
details.

If you want to control what functions Test::More will export, you
have to use the 'import' option.  For example, to import everything
but 'fail', you'd do:

  use Test::More tests => 23, import => ['!fail'];

Alternatively, you can use the plan() function.  Useful for when you
have to calculate the number of tests.

  use Test::More;
  plan tests => keys %Stuff * 3;

or for deciding between running the tests at all:

  use Test::More;
  if( $^O eq 'MacOS' ) {
      plan skip_all => 'Test irrelevant on MacOS';
  }
  else {
      plan tests => 42;
  }

=cut

sub plan {
    my(@plan) = @_;

    my $caller = caller;

    $Test->exported_to($caller);
    $Test->plan(@plan);

    my @imports = ();
    foreach my $idx (0..$#plan) {
        if( $plan[$idx] eq 'import' ) {
            @imports = @{$plan[$idx+1]};
            last;
        }
    }

    __PACKAGE__->_export_to_level(1, __PACKAGE__, @imports);
}

sub import {
    my($class) = shift;
    goto &plan;
}


=head2 Test names

By convention, each test is assigned a number in order.  This is
largely done automatically for you.  However, its often very useful to
assign a name to each test.  Which would you rather see:

  ok 4
  not ok 5
  ok 6

or

  ok 4 - basic multi-variable
  not ok 5 - simple exponential
  ok 6 - force == mass * acceleration

The later gives you some idea of what failed.  It also makes it easier
to find the test in your script, simply search for "simple
exponential".

All test functions take a name argument.  Its optional, but highly
suggested that you use it.


=head2 I'm ok, you're not ok.

The basic purpose of this module is to print out either "ok #" or "not
ok #" depending on if a given test succeeded or failed.  Everything
else is just gravy.

All of the following print "ok" or "not ok" depending on if the test
succeeded or failed.  They all also return true or false,
respectively.

=over 4

=item B<ok>

  ok($this eq $that, $test_name);

This simply evaluates any expression (C<$this eq $that> is just a
simple example) and uses that to determine if the test succeeded or
failed.  A true expression passes, a false one fails.  Very simple.

For example:

    ok( $exp{9} == 81,                   'simple exponential' );
    ok( Film->can('db_Main'),            'set_db()' );
    ok( $p->tests == 4,                  'saw tests' );
    ok( !grep !defined $_, @items,       'items populated' );

(Mnemonic:  "This is ok.")

$test_name is a very short description of the test that will be printed
out.  It makes it very easy to find a test in your script when it fails
and gives others an idea of your intentions.  $test_name is optional,
but we B<very> strongly encourage its use.

Should an ok() fail, it will produce some diagnostics:

    not ok 18 - sufficient mucus
    #     Failed test 18 (foo.t at line 42)

This is actually Test::Simple's ok() routine.

=cut

sub ok ($;$) {
    my($test, $name) = @_;
    $Test->ok($test, $name);
}

=item B<is>

=item B<isnt>

  is  ( $this, $that, $test_name );
  isnt( $this, $that, $test_name );

Similar to ok(), is() and isnt() compare their two arguments
with C<eq> and C<ne> respectively and use the result of that to
determine if the test succeeded or failed.  So these:

    # Is the ultimate answer 42?
    is( ultimate_answer(), 42,          "Meaning of Life" );

    # $foo isn't empty
    isnt( $foo, '',     "Got some foo" );

are similar to these:

    ok( ultimate_answer() eq 42,        "Meaning of Life" );
    ok( $foo ne '',     "Got some foo" );

(Mnemonic:  "This is that."  "This isn't that.")

So why use these?  They produce better diagnostics on failure.  ok()
cannot know what you are testing for (beyond the name), but is() and
isnt() know what the test was and why it failed.  For example this
test:

    my $foo = 'waffle';  my $bar = 'yarblokos';
    is( $foo, $bar,   'Is foo the same as bar?' );

Will produce something like this:

    not ok 17 - Is foo the same as bar?
    #     Failed test 1 (foo.t at line 139)
    #          got: 'waffle'
    #     expected: 'yarblokos'

So you can figure out what went wrong without rerunning the test.

You are encouraged to use is() and isnt() over ok() where possible,
however do not be tempted to use them to find out if something is
true or false!

  # XXX BAD!  $pope->isa('Catholic') eq 1
  is( $pope->isa('Catholic'), 1,        'Is the Pope Catholic?' );

This does not check if C<$pope->isa('Catholic')> is true, it checks if
it returns 1.  Very different.  Similar caveats exist for false and 0.
In these cases, use ok().

  ok( $pope->isa('Catholic') ),         'Is the Pope Catholic?' );

For those grammatical pedants out there, there's an C<isn't()>
function which is an alias of isnt().

=cut

sub is ($$;$) {
    $Test->is_eq(@_);
}

sub isnt ($$;$) {
    my($this, $that, $name) = @_;

    my $test;
    {
        local $^W = 0;   # so isnt(undef, undef) works quietly.
        $test = $this ne $that;
    }

    my $ok = $Test->ok($test, $name);

    unless( $ok ) {
        $that = defined $that ? "'$that'" : 'undef';

        $Test->diag(sprintf <<DIAGNOSTIC, $that);
it should not be %s
but it is.
DIAGNOSTIC

    }

    return $ok;
}

*isn't = \&isnt;


=item B<like>

  like( $this, qr/that/, $test_name );

Similar to ok(), like() matches $this against the regex C<qr/that/>.

So this:

    like($this, qr/that/, 'this is like that');

is similar to:

    ok( $this =~ /that/, 'this is like that');

(Mnemonic "This is like that".)

The second argument is a regular expression.  It may be given as a
regex reference (i.e. C<qr//>) or (for better compatibility with older
perls) as a string that looks like a regex (alternative delimiters are
currently not supported):

    like( $this, '/that/', 'this is like that' );

Regex options may be placed on the end (C<'/that/i'>).

Its advantages over ok() are similar to that of is() and isnt().  Better
diagnostics on failure.

=cut

sub like ($$;$) {
    $Test->like(@_);
}

=item B<can_ok>

  can_ok($module, @methods);
  can_ok($object, @methods);

Checks to make sure the $module or $object can do these @methods
(works with functions, too).

    can_ok('Foo', qw(this that whatever));

is almost exactly like saying:

    ok( Foo->can('this') && 
        Foo->can('that') && 
        Foo->can('whatever') 
      );

only without all the typing and with a better interface.  Handy for
quickly testing an interface.

=cut

sub can_ok ($@) {
    my($proto, @methods) = @_;
    my $class= ref $proto || $proto;

    my @nok = ();
    foreach my $method (@methods) {
        my $test = "'$class'->can('$method')";
        eval $test || push @nok, $method;
    }

    my $name;
    $name = @methods == 1 ? "$class->can($methods[0])" 
                          : "$class->can(...)";
    
    my $ok = $Test->ok( !@nok, $name );

    $Test->diag(map "$class->can('$_') failed\n", @nok);

    return $ok;
}

=item B<isa_ok>

  isa_ok($object, $class, $object_name);

Checks to see if the given $object->isa($class).  Also checks to make
sure the object was defined in the first place.  Handy for this sort
of thing:

    my $obj = Some::Module->new;
    isa_ok( $obj, 'Some::Module' );

where you'd otherwise have to write

    my $obj = Some::Module->new;
    ok( defined $obj && $obj->isa('Some::Module') );

to safeguard against your test script blowing up.

The diagnostics of this test normally just refer to 'the object'.  If
you'd like them to be more specific, you can supply an $object_name
(for example 'Test customer').

=cut

sub isa_ok ($$;$) {
    my($object, $class, $obj_name) = @_;

    my $diag;
    $obj_name = 'The object' unless defined $obj_name;
    my $name = "$obj_name isa $class";
    if( !defined $object ) {
        $diag = "$obj_name isn't defined";
    }
    elsif( !ref $object ) {
        $diag = "$obj_name isn't a reference";
    }
    elsif( !$object->isa($class) ) {
        $diag = "$obj_name isn't a '$class'";
    }

    my $ok;
    if( $diag ) {
        $ok = $Test->ok( 0, $name );
        $Test->diag("$diag\n");
    }
    else {
        $ok = $Test->ok( 1, $name );
    }

    return $ok;
}


=item B<pass>

=item B<fail>

  pass($test_name);
  fail($test_name);

Sometimes you just want to say that the tests have passed.  Usually
the case is you've got some complicated condition that is difficult to
wedge into an ok().  In this case, you can simply use pass() (to
declare the test ok) or fail (for not ok).  They are synonyms for
ok(1) and ok(0).

Use these very, very, very sparingly.

=cut

sub pass (;$) {
    $Test->ok(1, @_);
}

sub fail (;$) {
    $Test->ok(0, @_);
}

=back

=head2 Module tests

You usually want to test if the module you're testing loads ok, rather
than just vomiting if its load fails.  For such purposes we have
C<use_ok> and C<require_ok>.

=over 4

=item B<use_ok>

   BEGIN { use_ok($module); }
   BEGIN { use_ok($module, @imports); }

These simply use the given $module and test to make sure the load
happened ok.  Its recommended that you run use_ok() inside a BEGIN
block so its functions are exported at compile-time and prototypes are
properly honored.

If @imports are given, they are passed through to the use.  So this:

   BEGIN { use_ok('Some::Module', qw(foo bar)) }

is like doing this:

   use Some::Module qw(foo bar);


=cut

sub use_ok ($;@) {
    my($module, @imports) = @_;
    @imports = () unless @imports;

    my $pack = caller;

    eval <<USE;
package $pack;
require $module;
$module->import(\@imports);
USE

    my $ok = $Test->ok( !$@, "use $module;" );

    unless( $ok ) {
        chomp $@;
        $Test->diag(<<DIAGNOSTIC);
Tried to use '$module'.
Error:  $@
DIAGNOSTIC

    }

    return $ok;
}

=item B<require_ok>

   require_ok($module);

Like use_ok(), except it requires the $module.

=cut

sub require_ok ($) {
    my($module) = shift;

    my $pack = caller;

    eval <<REQUIRE;
package $pack;
require $module;
REQUIRE

    my $ok = $Test->ok( !$@, "require $module;" );

    unless( $ok ) {
        chomp $@;
        $Test->diag(<<DIAGNOSTIC);
#     Tried to require '$module'.
#     Error:  $@
DIAGNOSTIC

    }

    return $ok;
}

=back

=head2 Conditional tests

B<WARNING!> The following describes an I<experimental> interface that
is subject to change B<WITHOUT NOTICE>!  Use at your peril.

Sometimes running a test under certain conditions will cause the
test script to die.  A certain function or method isn't implemented
(such as fork() on MacOS), some resource isn't available (like a 
net connection) or a module isn't available.  In these cases it's
necessary to skip tests, or declare that they are supposed to fail
but will work in the future (a todo test).

For more details on skip and todo tests see L<Test::Harness>.

The way Test::More handles this is with a named block.  Basically, a
block of tests which can be skipped over or made todo.  It's best if I
just show you...

=over 4

=item B<SKIP: BLOCK>

  SKIP: {
      skip $why, $how_many if $condition;

      ...normal testing code goes here...
  }

This declares a block of tests to skip, $how_many tests there are,
$why and under what $condition to skip them.  An example is the
easiest way to illustrate:

    SKIP: {
        skip "Pigs don't fly here", 2 unless Pigs->can('fly');

        my $pig = Pigs->new;
        $pig->takeoff;

        ok( $pig->altitude > 0,         'Pig is airborne' );
        ok( $pig->airspeed > 0,         '  and moving'    );
    }

If pigs cannot fly, the whole block of tests will be skipped
completely.  Test::More will output special ok's which Test::Harness
interprets as skipped tests.  Its important to include $how_many tests
are in the block so the total number of tests comes out right (unless
you're using C<no_plan>, in which case you can leave $how_many off if
you like).

You'll typically use this when a feature is missing, like an optional
module is not installed or the operating system doesn't have some
feature (like fork() or symlinks) or maybe you need an Internet
connection and one isn't available.

=for _Future
See L</Why are skip and todo so weird?>

=cut

#'#
sub skip {
    my($why, $how_many) = @_;

    unless( defined $how_many ) {
        # $how_many can only be avoided when no_plan is in use.
        _carp "skip() needs to know \$how_many tests are in the block"
          unless $Test::Builder::No_Plan;
        $how_many = 1;
    }

    for( 1..$how_many ) {
        $Test->skip($why);
    }

    local $^W = 0;
    last SKIP;
}


=item B<TODO: BLOCK>

    TODO: {
        local $TODO = $why;

        ...normal testing code goes here...
    }

Declares a block of tests you expect to fail and $why.  Perhaps it's
because you haven't fixed a bug or haven't finished a new feature:

    TODO: {
        local $TODO = "URI::Geller not finished";

        my $card = "Eight of clubs";
        is( URI::Geller->your_card, $card, 'Is THIS your card?' );

        my $spoon;
        URI::Geller->bend_spoon;
        is( $spoon, 'bent',    "Spoon bending, that's original" );
    }

With a todo block, the tests inside are expected to fail.  Test::More
will run the tests normally, but print out special flags indicating
they are "todo".  Test::Harness will interpret failures as being ok.
Should anything succeed, it will report it as an unexpected success.

The nice part about todo tests, as opposed to simply commenting out a
block of tests, is it's like having a programmatic todo list.  You know
how much work is left to be done, you're aware of what bugs there are,
and you'll know immediately when they're fixed.

Once a todo test starts succeeding, simply move it outside the block.
When the block is empty, delete it.


=back

=head2 Comparison functions

Not everything is a simple eq check or regex.  There are times you
need to see if two arrays are equivalent, for instance.  For these
instances, Test::More provides a handful of useful functions.

B<NOTE> These are NOT well-tested on circular references.  Nor am I
quite sure what will happen with filehandles.

=over 4

=item B<is_deeply>

  is_deeply( $this, $that, $test_name );

Similar to is(), except that if $this and $that are hash or array
references, it does a deep comparison walking each data structure to
see if they are equivalent.  If the two structures are different, it
will display the place where they start differing.

B<NOTE> Display of scalar refs is not quite 100%

=cut

use vars qw(@Data_Stack);
my $DNE = bless [], 'Does::Not::Exist';
sub is_deeply {
    my($this, $that, $name) = @_;

    my $ok;
    if( !ref $this || !ref $that ) {
        $ok = $Test->is_eq($this, $that, $name);
    }
    else {
        local @Data_Stack = ();
        if( _deep_check($this, $that) ) {
            $ok = $Test->ok(1, $name);
        }
        else {
            $ok = $Test->ok(0, $name);
            $ok = $Test->diag(_format_stack(@Data_Stack));
        }
    }

    return $ok;
}

sub _format_stack {
    my(@Stack) = @_;

    my $var = '$FOO';
    my $did_arrow = 0;
    foreach my $entry (@Stack) {
        my $type = $entry->{type} || '';
        my $idx  = $entry->{'idx'};
        if( $type eq 'HASH' ) {
            $var .= "->" unless $did_arrow++;
            $var .= "{$idx}";
        }
        elsif( $type eq 'ARRAY' ) {
            $var .= "->" unless $did_arrow++;
            $var .= "[$idx]";
        }
        elsif( $type eq 'REF' ) {
            $var = "\${$var}";
        }
    }

    my @vals = @{$Stack[-1]{vals}}[0,1];
    my @vars = ();
    ($vars[0] = $var) =~ s/\$FOO/     \$got/;
    ($vars[1] = $var) =~ s/\$FOO/\$expected/;

    my $out = "Structures begin differing at:\n";
    foreach my $idx (0..$#vals) {
        my $val = $vals[$idx];
        $vals[$idx] = !defined $val ? 'undef' : 
                      $val eq $DNE  ? "Does not exist"
                                    : "'$val'";
    }

    $out .= "$vars[0] = $vals[0]\n";
    $out .= "$vars[1] = $vals[1]\n";

    return $out;
}


=item B<eq_array>

  eq_array(\@this, \@that);

Checks if two arrays are equivalent.  This is a deep check, so
multi-level structures are handled correctly.

=cut

#'#
sub eq_array  {
    my($a1, $a2) = @_;
    return 1 if $a1 eq $a2;

    my $ok = 1;
    my $max = $#$a1 > $#$a2 ? $#$a1 : $#$a2;
    for (0..$max) {
        my $e1 = $_ > $#$a1 ? $DNE : $a1->[$_];
        my $e2 = $_ > $#$a2 ? $DNE : $a2->[$_];

        push @Data_Stack, { type => 'ARRAY', idx => $_, vals => [$e1, $e2] };
        $ok = _deep_check($e1,$e2);
        pop @Data_Stack if $ok;

        last unless $ok;
    }
    return $ok;
}

sub _deep_check {
    my($e1, $e2) = @_;
    my $ok = 0;

    my $eq;
    {
        # Quiet uninitialized value warnings when comparing undefs.
        local $^W = 0; 

        if( $e1 eq $e2 ) {
            $ok = 1;
        }
        else {
            if( UNIVERSAL::isa($e1, 'ARRAY') and
                UNIVERSAL::isa($e2, 'ARRAY') )
            {
                $ok = eq_array($e1, $e2);
            }
            elsif( UNIVERSAL::isa($e1, 'HASH') and
                   UNIVERSAL::isa($e2, 'HASH') )
            {
                $ok = eq_hash($e1, $e2);
            }
            elsif( UNIVERSAL::isa($e1, 'REF') and
                   UNIVERSAL::isa($e2, 'REF') )
            {
                push @Data_Stack, { type => 'REF', vals => [$e1, $e2] };
                $ok = _deep_check($$e1, $$e2);
                pop @Data_Stack if $ok;
            }
            elsif( UNIVERSAL::isa($e1, 'SCALAR') and
                   UNIVERSAL::isa($e2, 'SCALAR') )
            {
                push @Data_Stack, { type => 'REF', vals => [$e1, $e2] };
                $ok = _deep_check($$e1, $$e2);
            }
            else {
                push @Data_Stack, { vals => [$e1, $e2] };
                $ok = 0;
            }
        }
    }

    return $ok;
}


=item B<eq_hash>

  eq_hash(\%this, \%that);

Determines if the two hashes contain the same keys and values.  This
is a deep check.

=cut

sub eq_hash {
    my($a1, $a2) = @_;
    return 1 if $a1 eq $a2;

    my $ok = 1;
    my $bigger = keys %$a1 > keys %$a2 ? $a1 : $a2;
    foreach my $k (keys %$bigger) {
        my $e1 = exists $a1->{$k} ? $a1->{$k} : $DNE;
        my $e2 = exists $a2->{$k} ? $a2->{$k} : $DNE;

        push @Data_Stack, { type => 'HASH', idx => $k, vals => [$e1, $e2] };
        $ok = _deep_check($e1, $e2);
        pop @Data_Stack if $ok;

        last unless $ok;
    }

    return $ok;
}

=item B<eq_set>

  eq_set(\@this, \@that);

Similar to eq_array(), except the order of the elements is B<not>
important.  This is a deep check, but the irrelevancy of order only
applies to the top level.

=cut

# We must make sure that references are treated neutrally.  It really
# doesn't matter how we sort them, as long as both arrays are sorted
# with the same algorithm.
sub _bogus_sort { local $^W = 0;  ref $a ? 0 : $a cmp $b }

sub eq_set  {
    my($a1, $a2) = @_;
    return 0 unless @$a1 == @$a2;

    # There's faster ways to do this, but this is easiest.
    return eq_array( [sort _bogus_sort @$a1], [sort _bogus_sort @$a2] );
}


=back

=head1 NOTES

Test::More is B<explicitly> tested all the way back to perl 5.004.

=head1 BUGS and CAVEATS

=over 4

=item Making your own ok()

This will not do what you mean:

    sub my_ok {
        ok( @_ );
    }

    my_ok( 2 + 2 == 5, 'Basic addition' );

since ok() takes it's arguments as scalars, it will see the length of
@_ (2) and always pass the test.  You want to do this instead:

    sub my_ok {
        ok( $_[0], $_[1] );
    }

The other functions act similarly.

=item The eq_* family have some caveats.

=item Test::Harness upgrades

no_plan and todo depend on new Test::Harness features and fixes.  If
you're going to distribute tests that use no_plan your end-users will
have to upgrade Test::Harness to the latest one on CPAN.

If you simply depend on Test::More, it's own dependencies will cause a
Test::Harness upgrade.

=back


=head1 HISTORY

This is a case of convergent evolution with Joshua Pritikin's Test
module.  I was largely unaware of its existence when I'd first
written my own ok() routines.  This module exists because I can't
figure out how to easily wedge test names into Test's interface (along
with a few other problems).

The goal here is to have a testing utility that's simple to learn,
quick to use and difficult to trip yourself up with while still
providing more flexibility than the existing Test.pm.  As such, the
names of the most common routines are kept tiny, special cases and
magic side-effects are kept to a minimum.  WYSIWYG.


=head1 SEE ALSO

L<Test::Simple> if all this confuses you and you just want to write
some tests.  You can upgrade to Test::More later (its forward
compatible).

L<Test> for a similar testing module.

L<Test::Harness> for details on how your test results are interpreted
by Perl.

L<Test::Unit> describes a very featureful unit testing interface.

L<Test::Inline> shows the idea of embedded testing.

L<SelfTest> is another approach to embedded testing.


=head1 AUTHORS

Michael G Schwern E<lt>schwern@pobox.comE<gt> with much inspiration from
Joshua Pritikin's Test module and lots of discussion with Barrie
Slaymaker and the perl-qa gang.


=head1 COPYRIGHT

Copyright 2001 by Michael G Schwern E<lt>schwern@pobox.comE<gt>.

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

See L<http://www.perl.com/perl/misc/Artistic.html>

=cut

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