<<< IF vary!!zip!!gzip,bzip2 == 'gzip';
    unzip   = 'gunzip';
    modpkg  = 'IO::Compress::Gzip';
    modpkgu = 'IO::Uncompress::Gunzip';
ELSE;
    unzip   = 'bunzip2';
    modpkg  = 'IO::Compress::Bzip2';
    modpkgu = 'IO::Uncompress::Bunzip2';
END ->>>
# Check that IO::Callback inter-operates with <<< modpkg >>>

use strict;
use warnings;

use Test::More;
BEGIN {
    eval 'use <<< modpkg >>> qw/<<< zip >>>/';
    plan skip_all => '<<< modpkg >>> required' if $@;

    eval 'use <<< modpkgu >>> qw/<<< unzip >>>/';
    plan skip_all => '<<< modpkgu >>> required' if $@;

    plan tests => 6;
}
use Test::NoWarnings;

use Fatal qw/close/;
use IO::Callback;

sub is_zipped ($$;$) {
    my ($zgot, $want, $comment) = @_;

    my $got;
    <<< unzip >>>(\$zgot, \$got) or die "<<< unzip >>> failed";
    is( $got, $want, $comment );
}

my $test_data = "foo\n" x 100;

my $lines = 0;
my $coderef_read_fh = IO::Callback->new('<', sub {
    return if $lines++ >= 100;
    return "foo\n";
});

my $compressed;
ok <<< zip >>>($coderef_read_fh, \$compressed), "<<< zip >>> from read coderef succeeded";
is_zipped $compressed, $test_data, "<<< zip >>> from read coderef correct";

my $got_close = 0;
my $got_data = '';
my $coderef_write_fh = IO::Callback->new('>', sub {
    my $buf = shift;
    if (length $buf) {
        $got_close and die "write after close";
        $got_data .= $buf;
    } else {
        ++$got_close;
    }
});

ok <<< zip >>>(\$test_data, $coderef_write_fh), "<<< zip >>> to write coderef succeeded";
close $coderef_write_fh;
is $got_close, 1, "write fh got close";
is_zipped $got_data, $test_data, "<<< zip >>> to write coderef correct";