<document source="test data">
    <section ids="perl-test" names="perl test">
        <title>
            Perl Test
        <paragraph>
            Supply both argument and content.
        <system_message level="1" line="6" source="test data" type="INFO">
            <paragraph>
                No directive entry for "perl" in module "Text::Restructured::Directive".
                Trying "perl" as canonical directive name.
        <system_message level="3" line="6" source="test data" type="ERROR">
            <paragraph>
                Error in "perl" directive:
                Cannot have both argument and content.
            <literal_block xml:space="preserve">
                .. perl:: $a = 1;
                   :literal:
                \n\
                   $a = 2;
        <paragraph>
            A paragraph.