core/modules/book/src/Tests/BookTest.php         | 30 +++++++++++++-----------
 core/modules/book/tests/modules/book_test.module |  1 +
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/core/modules/book/src/Tests/BookTest.php b/core/modules/book/src/Tests/BookTest.php
index 950b9dc..d2394cd 100644
--- a/core/modules/book/src/Tests/BookTest.php
+++ b/core/modules/book/src/Tests/BookTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\book\Tests;
 
 use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\simpletest\WebTestBase;
 use Drupal\user\RoleInterface;
@@ -125,6 +126,7 @@ public function testBookNavigationCacheContext() {
 
     // Enable the debug output.
     \Drupal::state()->set('book_test.debug_book_navigation_cache_context', TRUE);
+    Cache::invalidateTags(['book_test.debug_book_navigation_cache_context']);
 
     $this->drupalLogin($this->bookAuthor);
 
@@ -152,7 +154,7 @@ public function testBookNavigationCacheContext() {
   /**
    * Tests saving the book outline on an empty book.
    */
-  function atestEmptyBook() {
+  function testEmptyBook() {
     // Create a new empty book.
     $this->drupalLogin($this->bookAuthor);
     $book = $this->createBookNode('new');
@@ -167,7 +169,7 @@ function atestEmptyBook() {
   /**
    * Tests book functionality through node interfaces.
    */
-  function atestBook() {
+  function testBook() {
     // Create new book.
     $nodes = $this->createBook();
     $book = $this->book;
@@ -371,7 +373,7 @@ function createBookNode($book_nid, $parent = NULL) {
   /**
    * Tests book export ("printer-friendly version") functionality.
    */
-  function atestBookExport() {
+  function testBookExport() {
     // Create a book.
     $nodes = $this->createBook();
 
@@ -416,7 +418,7 @@ function atestBookExport() {
   /**
    * Tests the functionality of the book navigation block.
    */
-  function atestBookNavigationBlock() {
+  function testBookNavigationBlock() {
     $this->drupalLogin($this->adminUser);
 
     // Enable the block.
@@ -439,7 +441,7 @@ function atestBookNavigationBlock() {
   /**
    * Tests the book navigation block when an access module is installed.
    */
-  function atestNavigationBlockOnAccessModuleInstalled() {
+  function testNavigationBlockOnAccessModuleInstalled() {
     $this->drupalLogin($this->adminUser);
     $block = $this->drupalPlaceBlock('book_navigation', array('block_mode' => 'book pages'));
 
@@ -470,7 +472,7 @@ function atestNavigationBlockOnAccessModuleInstalled() {
   /**
    * Tests the access for deleting top-level book nodes.
    */
-   function atestBookDelete() {
+   function testBookDelete() {
      $node_storage = $this->container->get('entity.manager')->getStorage('node');
      $nodes = $this->createBook();
      $this->drupalLogin($this->adminUser);
@@ -498,7 +500,7 @@ function atestBookDelete() {
   /*
    * Tests node type changing machine name when type is a book allowed type.
    */
-  function atestBookNodeTypeChange() {
+  function testBookNodeTypeChange() {
     $this->drupalLogin($this->adminUser);
     // Change the name, machine name and description.
     $edit = array(
@@ -591,7 +593,7 @@ function atestBookNodeTypeChange() {
   /**
    * Tests re-ordering of books.
    */
-  public function atestBookOrdering() {
+  public function testBookOrdering() {
     // Create new book.
     $this->createBook();
     $book = $this->book;
@@ -619,7 +621,7 @@ public function atestBookOrdering() {
   /**
    * Tests outline of a book.
    */
-  public function atestBookOutline() {
+  public function testBookOutline() {
     $this->drupalLogin($this->bookAuthor);
 
     // Create new node not yet a book.
@@ -673,7 +675,7 @@ public function atestBookOutline() {
   /**
    * Tests that saveBookLink() returns something.
    */
-  public function atestSaveBookLink() {
+  public function testSaveBookLink() {
     $book_manager = \Drupal::service('book.manager');
 
     // Mock a link for a new book.
@@ -693,7 +695,7 @@ public function atestSaveBookLink() {
   /**
    * Tests the listing of all books.
    */
-  public function atestBookListing() {
+  public function testBookListing() {
     // Create a new book.
     $this->createBook();
 
@@ -709,7 +711,7 @@ public function atestBookListing() {
   /**
    * Tests the administrative listing of all books.
    */
-  public function atestAdminBookListing() {
+  public function testAdminBookListing() {
     // Create a new book.
     $this->createBook();
 
@@ -722,7 +724,7 @@ public function atestAdminBookListing() {
   /**
    * Tests the administrative listing of all book pages in a book.
    */
-  public function atestAdminBookNodeListing() {
+  public function testAdminBookNodeListing() {
     // Create a new book.
     $this->createBook();
     $this->drupalLogin($this->adminUser);
@@ -739,7 +741,7 @@ public function atestAdminBookNodeListing() {
   /**
    * Ensure the loaded book in hook_node_load() does not depend on the user.
    */
-  public function atestHookNodeLoadAccess() {
+  public function testHookNodeLoadAccess() {
     \Drupal::service('module_installer')->install(['node_access_test']);
 
     // Ensure that the loaded book in hook_node_load() does NOT depend on the
diff --git a/core/modules/book/tests/modules/book_test.module b/core/modules/book/tests/modules/book_test.module
index 2f868a4..939e756 100644
--- a/core/modules/book/tests/modules/book_test.module
+++ b/core/modules/book/tests/modules/book_test.module
@@ -15,6 +15,7 @@
  * Implements hook_page_attachments().
  */
 function book_test_page_attachments(array &$page) {
+  $page['#cache']['tags'][] = 'book_test.debug_book_navigation_cache_context';
   if (\Drupal::state()->get('book_test.debug_book_navigation_cache_context', FALSE)) {
     drupal_set_message(\Drupal::service('cache_contexts_manager')->convertTokensToKeys(['route.book_navigation'])->getKeys()[0]);
   }