HiddenFieldSelector.php

<?php

namespace Drupal\Tests;

use Behat\Mink\Selector\PartialNamedSelector;

/**
 * Extends PartialNamedSelector to allow retrieval of hidden fields.
 *
 * @see \Behat\Mink\Selector\PartialNamedSelector
 */
class HiddenFieldSelector extends PartialNamedSelector {
    
    /**
     * {@inheritdoc}
     */
    public function __construct() {
        $xpath = ".//input[%lowercaseType% = 'hidden' and (%idOrNameMatch% or %valueMatch%)]";
        $this->registerNamedXpath('hidden_field', $xpath);
        parent::__construct();
    }

}