Update to Drupal 8.0.5. For more information, see https://www.drupal.org/node/2679347

core/modules/book/tests/modules/book_breadcrumb_test/book_breadcrumb_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Book module breadcrumb tests'
+type: module
+description: 'Support module for book module breadcrumb testing.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/book/tests/modules/book_breadcrumb_test/book_breadcrumb_test.module

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+<?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;
+}

core/modules/book/tests/modules/book_breadcrumb_test/config/install/book_breadcrumb_test.settings.yml

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+'hide': false

core/modules/book/tests/modules/book_breadcrumb_test/config/schema/book_breadcrumb_test.schema.yml

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+# Schema for the configuration files of the book_breadcrumb_test module.
+
+book_breadcrumb_test.settings:
+  type: config_object
+  label: 'Book Breadcrumb Test module settings'
+  mapping:
+    hide:
+      type: boolean
+      label: 'Setting for hiding content'