Im attempting to give a little code for an already made thumbnail wordpress plugin.

Essentially i wish to obtain the image src of the image and also the just print it in to the HTML, but each time i run it, its just echoing 'Array'

This is exactly what i've to date.

$testing = wp_get_attachment_image_src($post_thumbnail_id);
$html = '<a href="'.$testing.'">';

Any help could be greatly appreciated.

Based on the Wordpress Documentation for wp_get_attachment_image_src the return value is:

An assortment that contains:

$image[] => url

$image[1] => width

$image[2] => height

Therefore, this is exactly what you'll need:

$html = '<a href="'.$testing[0].'">';