Sets and clears values from a Drupal entity reference field widget.

EntityReferenceContext.php

<?php

use Behat\Mink\Mink;
use Behat\MinkExtension\Context\MinkAwareContext;

/**
 * Class EntityReferenceContext.
 */
class EntityReferenceContext implements MinkAwareContext {

  /**
   * Mink instance.
   *
   * @var \Behat\Mink\Mink
   */
  protected $mink;

  /**
   * Mink parameters.
   *
   * @var array
   */
  protected $minkParameters = [];

  /**
   * {@inheritdoc}
   */
  public function setMink(Mink $mink) {
    $this->mink = $mink;
  }

  /**
   * {@inheritdoc}
   */
  public function setMinkParameters(array $parameters) {
    $this->minkParameters = $parameters;
  }

  /**
   * Clears values from an entity reference widget.
   *
   * @When I clear the references for :name
   */
  public function assertClearReferences($name) {
    $widget = $this->findEntityReferenceWidget($name);
    foreach ($widget->findAll('css', 'table input') as $inputEl) {
      /** @var \Behat\Mink\Element\NodeElement $inputEl */
      $inputEl->setValue('');
    }
  }

  /**
   * Add a value to an entity reference widget.
   *
   * @When I set a reference to :value for :name
   */
  public function assertAddReference($value, $name) {
    $widget = $this->findEntityReferenceWidget($name);

    /** @var \Behat\Mink\Element\NodeElement[] $inputEls */
    $inputEls = $widget->findAll('css', 'table input');
    $inputEl = array_pop($inputEls);

    // If the last input already has a value, we'll need to press the "add more"
    // button and try again.
    if ($inputEl->getValue()) {
      // @TODO: Make this compatible with JS browsers (AJAX interaction).
      $widget->pressButton('Add another item');
      $inputEls = $widget->findAll('css', 'table input');
      $inputEl = array_pop($inputEls);
    }

    $inputEl->setValue($value);
  }

  /**
   * Finds an entity reference widget.
   *
   * @param string $name
   *   The field name.
   *
   * @return \Behat\Mink\Element\NodeElement
   *   The widget.
   *
   * @throws \Exception
   *   The the widget is not found.
   */
  protected function findEntityReferenceWidget($name) {
    $name = trim($name);

    // Find all the widgets.
    /** @var \Behat\Mink\Element\NodeElement[] $tables */
    $widgets = $this->mink->getSession()->getPage()->findAll('css', '.field--widget-entity-reference-autocomplete');

    // Filter down to ones with labels matching the name.
    $widgets = array_filter($widgets, function ($widget) use ($name) {
      /** @var \Behat\Mink\Element\NodeElement $widget */
      if ($label = $widget->find('css', '.label')) {
        return trim($label->getText()) == $name;
      }
      return FALSE;
    });

    // Return the first one.
    if (!$widget = reset($widgets)) {
      throw new \Exception(sprintf('Unable to find entity reference field "%s".', $name));
    }

    return $widget;
  }

}