I am building a plugin and have used the simple query:

function getTotal($postType){
  $total = 0;

  $args = array(
   'post_type' => $postType,
  );
  $metrics = new WP_Query( $args );

  foreach( $metrics->get_posts() as $post ) {
      $total++;
  }

  wp_reset_postdata();

  return $total;
}

But the moment I add this code to my plugin, the following error:

Fatal error: Uncaught Error: Call to undefined function is_user_logged_in() in C:xampphtdocssamwp-includesclass-wp-query.php:2352 Stack trace: #0 C:xampphtdocssamwp-includesclass-wp-query.php(3222): WP_Query->get_posts() #1 C:xampphtdocssamwp-includesclass-wp-query.php(3328): WP_Query->query(Array) #2 C:xampphtdocssamwp-contentpluginssample_pluginModelsdataModels.php(62): WP_Query->__construct(Array) #3 C:xampphtdocssamwp-contentpluginssample_pluginViewscounselorTable.php(3): getCounselors() #4 C:xampphtdocssamwp-contentpluginssample_pluginsample_plugin.php(20): require(‘C:xampphtdocs…’) #5 C:xampphtdocssamwp-settings.php(305): include_once(‘C:xampphtdocs…’) #6 C:xampphtdocssamwp-config.php(91): require_once(‘C:xampphtdocs…’) #7 C:xampphtdocssamwp-load.php(37): require_once(‘C:xampphtdocs…’) #8 C:xampphtdocssamwp-blog-header.php(13): require_once(‘C:xampphtdocs…’) #9 C:xampphtdocssamindex.php(17): require(‘C:xampphtdocs. in C:xampphtdocssamwp-includesclass-wp-query.php on line 2352

I’ve been looking for some time now, but can’t find any direct explanation for the issue here. Guidance please?