<?php
$args_list = array(
    'taxonomy' => 'group', // Registered tax name
    'show_count' => true,
    'hierarchical' => false,
    'echo' => '0',
);
$entries = get_categories('title_li=&orderby=name&hide_empty=0&taxonomy=group');
$current_selected_cat = $instance['testi_cat'];
foreach ($entries as $key => $entry)

                    {
                        $id = $entry->term_id;
                        $title = $entry->name;

                        $checked = '';

                        if($current_selected_cat) {

                            foreach ($current_selected_cat as $entry2)
                            {
                                if($entry2 == $id)
                                {
                                    $checked = ' checked="checked" ';

                                }
                            }
                        }

                        echo '<input type="checkbox"  name="'.$this->get_field_name('testi_cat').'[]" value="' . $id . '"' . $checked . '> ' . $title . '<br />';
                    }
?>