how to test a wp plugin

hi ,

there is a plugin, written by another user.
i have activated that plugin in WP. It works fine.

Now i want to do some modifications and test that plugin. (dispay variables..add variables etc)
How can i do this without running the plugin

Say plugin file is myplugin.php
Can i access this pluging via my site url… like http://www.mysite.com/wp-content/plugin/myplugin.php

But then it says, it missing this and that file…

Need your assistance. How to run this plugin

—————Pluging code is as follows———–

<?php
/*
Plugin Name: Deal Parser
Description: Parses deal site and adds content as post
*/

add_action('admin_menu', 'deal_parser_menu');

function deal_parser_menu()
{
    add_menu_page('Deal Parser', 'Deal Parser', 'manage_options', 'dealparser', 'deal_parser_page', '', 6);
}

function deal_parser_page()
{
    ?>
    <script>
        (function ($) {
            $(document).ready(function () {

                var ajaxurl = '<?php echo admin_url('admin-ajax.php'); ?>';
                $('#runner').on('click', function () {
                    var realthis = $(this);
                    $(this).prop('disabled', true);
                    $(this).after('<img style="margin-left:20px" id="theloader" src="<?=plugins_url('deal-parser/images/ajax-loader.gif') ?>">');

                    $.post(
                        ajaxurl,
                        {
                            'action': 'fetch_site'
                        },
                        function (response) {
                            $('#frameholder').html(response);
                            $('#theloader').remove();
                            $(realthis).prop('disabled', false);

                        }
                    );
                })
            });
        })(jQuery);

    </script>

    <br>  <br>  <br>
    <input type="submit" autocomplete="off" value="Run parser manually now" class="button" id="runner" name="">
    <div id="frameholder"></div>
<?
}

function print_pre($val)
{
    echo "<pre>";
    print_r($val);
    echo "</pre>";
    die();
}

add_action('wp_ajax_fetch_site', 'fetch_site');

function fetch_site()
{

    global $wpdb;
    echo "<br>Bot starting to run..";
    echo "<br>Going to http://www.wow.lk/deals/home.jsp ..";

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'http://www.wow.lk/deals/home.jsp');
    curl_setopt($ch, CURLOPT_USERAGENT, 'Googlebot/2.1 (http://www.googlebot.com/bot.html)');
    curl_setopt($ch, CURLOPT_REFERER, 'http://www.google.com');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_COOKIESESSION, true);
    curl_setopt($ch, CURLOPT_COOKIEJAR, 'wow.txt'); //could be empty, but cause problems on some hosts
    curl_setopt($ch, CURLOPT_COOKIEFILE, 'wow.txt'); //could be empty, but cause problems on some hosts
    $answer = curl_exec($ch);
    if (curl_error($ch)) {
        echo curl_error($ch);
    }

    include_once('simple_html_dom.php');

    $html = str_get_html($answer);

    $ret = $html->find('.marginBotm10px a');

    krsort($ret);

    foreach ($ret as $thisdeal) {
        global $wpdb;
        echo "<br>Going to http://www.wow.lk" . $thisdeal->attr['href'] . " ..";
        curl_setopt($ch, CURLOPT_URL, "http://www.wow.lk" . $thisdeal->attr['href']);
        $answer = curl_exec($ch);

        $html2 = str_get_html($answer);

        $ret2 = $html2->find('h1.marginBotm10px', 0);

        /*
        $check = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE post_title = '" . trim($ret2->innertext) . "' and post_status='published'");

        print_pre(trim($ret2->innertext));
        if ($check) {
            echo "<br> The deal " . trim($ret2->innertext) . ' already exists, deal updated';
            continue;
        }

        */
        $title = trim($ret2->innertext);
        if (get_page_by_title($title, 'OBJECT', 'seller')) :

            echo "<br> The deal " . trim($ret2->innertext) . ' already exists, deal updated';

            continue;

        endif;

		 echo "<br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/>";
			 echo "**************************************************";

        $ret3 = $html2->find('.dealblock_content_info_image', 0);

        $imageurl = $ret3->attr['src'];
        $upload_dir = wp_upload_dir();
        $image_data = file_get_contents($imageurl);
        $filename = basename($imageurl);
        $pieces = explode('.', $filename);

        $filenamenew = $pieces[0] . time();
        $filename = $filenamenew . "." . $pieces[1];

        if (wp_mkdir_p($upload_dir['path']))
            $file = $upload_dir['path'] . '/' . $filename;
        else
            $file = $upload_dir['basedir'] . '/' . $filename;
        file_put_contents($file, $image_data);

        $fileurl = str_replace("/home/zerandib/public_html/samplesite/", "http://ustradeads.com/samplesite/", $file);

        $ret4 = $html2->find('#wow_deal_bigtextarea', 0);
        $ret5 = $html2->find('#wow_deal_bigtextarea', 1);

        $ret6 = $html2->find('#wow_deal_validity', 0)->find('p', 0)->innertext;

        $ret6 = str_replace('of ','',$ret6);
        $piecesdate = explode("to", trim($ret6));

        $dealstart = strtotime(trim($piecesdate[0]));

        if($dealstart > time())
        {
            $dealstart = time();
        }
        if(!is_int($dealstart)) print_pre($dealstart);
        $dealend = strtotime(str_replace('.', '', trim($piecesdate[1])));

        $our_price = str_replace(',','',str_replace('Rs ','',trim($html2->find('.dealblock_price_to',0)->innertext)));

        $current_price = str_replace(',','',str_replace('Rs ','',trim($html2->find('.dealblock_price_from',0)->innertext)));

		echo "************";
		echo "<br/>";
		echo $our_price;
		echo "************";
		echo $current_price;
		echo "<br/>";
		echo "************";

		print_pre("**************************");
		print_pre($our_price);
		print_pre("**************************");
		print_pre($current_price);

        $sold_count =$html2->find('#sold_count', 0)->innertext;
        $my_post = array(
            'post_title' => trim($ret2->innertext),
            'post_content' => '<div class="dealpage_header">
<h3><a href="' . $fileurl . '"><img class="alignnone  wp-image-9" src="' . $fileurl . '" alt="2"/></a></h3>
<a target="_blank" href="http://www.wow.lk' . $thisdeal->attr['href'] . '"><button>Get This Deal</button></a>
<h3>Deal Terms & Conditions</h3>
</div>
<div id="wow_deal_bigtextarea" class="alpha omega squre_border marginTB10px">
' . $ret4->innertext . '
</div>
<div class="dealpage_header">
<h3>About Deal</h3>
</div>
<div id="wow_deal_bigtextarea" class="alpha omega squre_border margintop10px marginBotm30px">
' . $ret5->innertext . '

</div>',
            'post_status' => 'publish',
            'post_author' => 1,
            'post_category' => array(8, 39),
            'post_type' => 'seller'
        );

        $post_ID = wp_insert_post($my_post);
        $post_url = get_the_permalink($post_ID);

        $wpdb->insert("wp_postmeta", array(
            "post_id" => $post_ID,
            "meta_key" => "coupon_start_date_time",
            "meta_value" => $dealstart
        ));

        $wpdb->insert("wp_postmeta", array(
                "post_id" => $post_ID,
                "meta_key" => "coupon_end_date_time",
                "meta_value" => $dealend
            ));

        $wpdb->insert("wp_postmeta", array(
            "post_id" => $post_ID,
            "meta_key" => "our_price",
            "meta_value" => $our_price
        ));

        $wpdb->insert("wp_postmeta", array(
            "post_id" => $post_ID,
            "meta_key" => "current_price",
            "meta_value" => $current_price
        ));

        $wpdb->insert("wp_postmeta", array(
            "post_id" => $post_ID,
            "meta_key" => "file_name",
            "meta_value" => $fileurl
        ));
        $wpdb->insert("wp_postmeta", array(
            "post_id" => $post_ID,
            "meta_key" => "status",
            "meta_value" => 1
        ));

   echo "<br> Deal with title : " . trim($ret2->innertext) . " added successfully. View post : <a href='" . $post_url . "' target='_blank'>" . $post_url . "</a>";

}

}

?>