--- /dev/null
+<?php
+
+namespace Drupal\Tests\book\Kernel\Migrate\d6;
+
+use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
+use Drupal\node\Entity\Node;
+
+/**
+ * Upgrade book structure.
+ *
+ * @group migrate_drupal_6
+ */
+class MigrateBookTest extends MigrateDrupal6TestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['book', 'menu_ui'];
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setUp() {
+ parent::setUp();
+ $this->installSchema('book', ['book']);
+ $this->installSchema('node', ['node_access']);
+ $this->migrateContent();
+ $this->executeMigrations(['d6_node', 'd6_book']);
+ }
+
+ /**
+ * Tests the Drupal 6 book structure to Drupal 8 migration.
+ */
+ public function testBook() {
+ $nodes = Node::loadMultiple([4, 5, 6, 7, 8]);
+ $this->assertIdentical('4', $nodes[4]->book['bid']);
+ $this->assertIdentical('0', $nodes[4]->book['pid']);
+
+ $this->assertIdentical('4', $nodes[5]->book['bid']);
+ $this->assertIdentical('4', $nodes[5]->book['pid']);
+
+ $this->assertIdentical('4', $nodes[6]->book['bid']);
+ $this->assertIdentical('5', $nodes[6]->book['pid']);
+
+ $this->assertIdentical('4', $nodes[7]->book['bid']);
+ $this->assertIdentical('5', $nodes[7]->book['pid']);
+
+ $this->assertIdentical('8', $nodes[8]->book['bid']);
+ $this->assertIdentical('0', $nodes[8]->book['pid']);
+
+ $tree = \Drupal::service('book.manager')->bookTreeAllData(4);
+ $this->assertIdentical('4', $tree['49990 Node 4 4']['link']['nid']);
+ $this->assertIdentical('5', $tree['49990 Node 4 4']['below']['50000 Node 5 5']['link']['nid']);
+ $this->assertIdentical('6', $tree['49990 Node 4 4']['below']['50000 Node 5 5']['below']['50000 Node 6 6']['link']['nid']);
+ $this->assertIdentical('7', $tree['49990 Node 4 4']['below']['50000 Node 5 5']['below']['50000 Node 7 7']['link']['nid']);
+ $this->assertIdentical([], $tree['49990 Node 4 4']['below']['50000 Node 5 5']['below']['50000 Node 6 6']['below']);
+ $this->assertIdentical([], $tree['49990 Node 4 4']['below']['50000 Node 5 5']['below']['50000 Node 7 7']['below']);
+ }
+
+}