Optimize the code

The code must be optimized a little. Just to make an example, the code could be changed from

$module_name = 'wordpress_import';
$dir = drupal_get_path('module', $module_name) .'/tests';

to

$dir = drupal_get_path('module', 'wordpress_import') .'/tests';

especially when $module_name is used just once on the function code.