Behat Context for checking field configuration in Drupal 8

FieldContext.php

<?php

use Behat\Behat\Context\Context;

/**
 * Defines application features from the specific context.
 */
class FieldContext implements Context {

  /**
   * Verify a field exists on an entity bundle.
   *
   * @Then :bundle type :entity_type entities have a(n) :field_type field :field_name
   */
  public function assertEntityTypeFieldType($entity_type, $bundle, $field_type, $field_name) {
    /** @var \Drupal\Core\Entity\EntityFieldManagerInterface $fieldManager */
    $fieldManager = \Drupal::service('entity_field.manager');
    $fieldDefinitions = $fieldManager->getFieldDefinitions($entity_type, $bundle);

    // Verify field set on entity type, bundle.
    if (!array_key_exists($field_name, $fieldDefinitions)) {
      throw new \Exception(sprintf('No field "%s" exists on "%s" type "%s" entities.', $field_name, $bundle, $entity_type));
    }

    // Verify type.
    if ($fieldDefinitions[$field_name]->getType() != $field_type) {
      throw new \Exception(sprintf('No field "%s" on "%s" type "%s" entities is not type "%s".', $field_name, $bundle, $entity_type, $field_type));
    }
  }

}