import click


if click.__version__ >= '3.0':
    def test_legacy_callbacks(runner):
        def legacy_callback(ctx, value):
            return value.upper()

        @click.command()
        @click.option('--foo', callback=legacy_callback)
        def cli(foo):
            click.echo(foo)

        result = runner.invoke(cli, ['--foo', 'wat'])
        assert result.exit_code == 0
        assert 'WAT' in result.output
        assert 'Invoked legacy parameter callback' in result.output