source: vendor/perl/5.8.8/lib/autouse.t

#!./perl

BEGIN {
    chdir 't' if -d 't';
    @INC = '../lib';
    require Config;
    if (($Config::Config{'extensions'} !~ m!\bList/Util\b!) ){
        print "1..0 # Skip -- Perl configured without List::Util module\n";
        exit 0;
    }
}

use Test;
BEGIN { plan tests => 10; }

BEGIN {
    require autouse;
    eval {
        "autouse"->import('List::Util' => 'List::Util::first(&@)');
    };
    ok( !$@ );

    eval {
        "autouse"->import('List::Util' => 'Foo::min');
    };
    ok( $@, qr/^autouse into different package attempted/ );

    "autouse"->import('List::Util' => qw(max first(&@)));
}

my @a = (1,2,3,4,5.5);
ok( max(@a), 5.5);


# first() has a prototype of &@.  Make sure that's preserved.
ok( (first { $_ > 3 } @a), 4);


# Example from the docs.
use autouse 'Carp' => qw(carp croak);

{
    my @warning;
    local $SIG{__WARN__} = sub { push @warning, @_ };
    carp "this carp was predeclared and autoused\n";
    ok( scalar @warning, 1 );
    ok( $warning[0], qr/^this carp was predeclared and autoused\n/ );

    eval { croak "It is but a scratch!" };
    ok( $@, qr/^It is but a scratch!/);
}


# Test that autouse's lazy module loading works.  We assume that nothing
# involved in this test uses Text::Soundex, which is pretty safe.
use autouse 'Text::Soundex' => qw(soundex);

my $mod_file = 'Text/Soundex.pm'; # just fine and portable for %INC
ok( !exists $INC{$mod_file} );
ok( soundex('Basset'), 'B230' );
ok( exists $INC{$mod_file} );