diff --git a/core/modules/book/tests/src/Functional/BookTest.php b/core/modules/book/tests/src/Functional/BookTest.php
index 66edec9..d7771f0 100644
--- a/core/modules/book/tests/src/Functional/BookTest.php
+++ b/core/modules/book/tests/src/Functional/BookTest.php
@@ -335,15 +335,20 @@ public function generateOutlinePattern($nodes) {
    *   A book node ID or set to 'new' to create a new book.
    * @param int|null $parent
    *   (optional) Parent book reference ID. Defaults to NULL.
+   * @param string $submit
+   *   (optional) Value of the submit button whose click is to be emulated.
+   *   Defaults to 'Save'.
    *
    * @return \Drupal\node\NodeInterface
    *   The created node.
    */
-  public function createBookNode($book_nid, $parent = NULL) {
+  public function createBookNode($book_nid, $parent = NULL, $submit = NULL) {
     // $number does not use drupal_static as it should not be reset
     // since it uniquely identifies each call to createBookNode().
     static $number = 0; // Used to ensure that when sorted nodes stay in same order.
 
+    $submit = $submit ?: t('Save');
+
     $edit = [];
     $edit['title[0][value]'] = str_pad($number, 2, '0', STR_PAD_LEFT) . ' - SimpleTest test node ' . $this->randomMachineName(10);
     $edit['body[0][value]'] = 'SimpleTest test body ' . $this->randomMachineName(32) . ' ' . $this->randomMachineName(32);
@@ -353,13 +358,13 @@ public function createBookNode($book_nid, $parent = NULL) {
       $this->drupalPostForm('node/add/book', $edit, t('Change book (update list of parents)'));
 
       $edit['book[pid]'] = $parent;
-      $this->drupalPostForm(NULL, $edit, t('Save'));
+      $this->drupalPostForm(NULL, $edit, $submit);
       // Make sure the parent was flagged as having children.
       $parent_node = \Drupal::entityManager()->getStorage('node')->loadUnchanged($parent);
       $this->assertFalse(empty($parent_node->book['has_children']), 'Parent node is marked as having children');
     }
     else {
-      $this->drupalPostForm('node/add/book', $edit, t('Save'));
+      $this->drupalPostForm('node/add/book', $edit, $submit);
     }
 
     // Check to make sure the book node was created.