--- /dev/null
+<?php
+
+/**
+ * @file
+ * Test module for testing the book module breadcrumb.
+ */
+
+use Drupal\Core\Access\AccessResultForbidden;
+use Drupal\Core\Access\AccessResultNeutral;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\node\NodeInterface;
+
+/**
+ * Implements hook_node_access().
+ */
+function book_breadcrumb_test_node_access(NodeInterface $node, $operation, AccountInterface $account) {
+ $config = \Drupal::config('book_breadcrumb_test.settings');
+ if ($config->get('hide') && $node->getTitle() == "you can't see me" && $operation == 'view') {
+ $access = new AccessResultForbidden();
+ }
+ else {
+ $access = new AccessResultNeutral();
+ }
+ $access->addCacheableDependency($config);
+ $access->addCacheableDependency($node);
+ return $access;
+}