class BookRelationshipTest

class BookRelationshipTest extends ViewTestBase {
    
    /**
     * Views used by this test.
     *
     * @var array
     */
    public static $testViews = [
        'test_book_view',
    ];
    
    /**
     * Modules to install.
     *
     * @var array
     */
    protected static $modules = [
        'book_test_views',
        'book',
        'views',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * A book node.
     *
     * @var object
     */
    protected $book;
    
    /**
     * A user with permission to create and edit books.
     *
     * @var object
     */
    protected $bookAuthor;
    
    /**
     * {@inheritdoc}
     */
    protected function setUp($import_test_views = TRUE, $modules = []) : void {
        parent::setUp($import_test_views, $modules);
        // Create users.
        $this->bookAuthor = $this->drupalCreateUser([
            'create new books',
            'create book content',
            'edit own book content',
            'add content to books',
        ]);
        ViewTestData::createTestViews(static::class, [
            'book_test_views',
        ]);
    }
    
    /**
     * Creates a new book with a page hierarchy.
     */
    protected function createBook() {
        // Create new book.
        $this->drupalLogin($this->bookAuthor);
        $this->book = $this->createBookNode('new');
        $book = $this->book;
        $nodes = [];
        // Node 0.
        $nodes[] = $this->createBookNode($book->id());
        // Node 1.
        $nodes[] = $this->createBookNode($book->id(), $nodes[0]->book['nid']);
        // Node 2.
        $nodes[] = $this->createBookNode($book->id(), $nodes[1]->book['nid']);
        // Node 3.
        $nodes[] = $this->createBookNode($book->id(), $nodes[2]->book['nid']);
        // Node 4.
        $nodes[] = $this->createBookNode($book->id(), $nodes[3]->book['nid']);
        // Node 5.
        $nodes[] = $this->createBookNode($book->id(), $nodes[4]->book['nid']);
        // Node 6.
        $nodes[] = $this->createBookNode($book->id(), $nodes[5]->book['nid']);
        // Node 7.
        $nodes[] = $this->createBookNode($book->id(), $nodes[6]->book['nid']);
        $this->drupalLogout();
        return $nodes;
    }
    
    /**
     * Creates a book node.
     *
     * @param int|string $book_nid
     *   A book node ID or set to 'new' to create a new book.
     * @param int|null $parent
     *   (optional) Parent book reference ID. Defaults to NULL.
     *
     * @return \Drupal\node\NodeInterface
     *   The book node.
     */
    protected function createBookNode($book_nid, $parent = NULL) {
        // $number does not use drupal_static as it should not be reset
        // since it uniquely identifies each call to createBookNode().
        // Used to ensure that when sorted nodes stay in same order.
        static $number = 0;
        $edit = [];
        $edit['title[0][value]'] = $number . ' - test node ' . $this->randomMachineName(10);
        $edit['body[0][value]'] = 'test body ' . $this->randomMachineName(32) . ' ' . $this->randomMachineName(32);
        $edit['book[bid]'] = $book_nid;
        if ($parent !== NULL) {
            $this->drupalGet('node/add/book');
            $this->submitForm($edit, 'Change book (update list of parents)');
            $edit['book[pid]'] = $parent;
            $this->submitForm($edit, 'Save');
            // Make sure the parent was flagged as having children.
            $parent_node = \Drupal::entityTypeManager()->getStorage('node')
                ->loadUnchanged($parent);
            $this->assertNotEmpty($parent_node->book['has_children'], 'Parent node is marked as having children');
        }
        else {
            $this->drupalGet('node/add/book');
            $this->submitForm($edit, 'Save');
        }
        // Check to make sure the book node was created.
        $node = $this->drupalGetNodeByTitle($edit['title[0][value]']);
        $this->assertNotNull($node === FALSE ? NULL : $node, 'Book node found in database.');
        $number++;
        return $node;
    }
    
    /**
     * Tests using the views relationship.
     */
    public function testRelationship() : void {
        // Create new book.
        
        /** @var \Drupal\node\NodeInterface[] $nodes */
        $nodes = $this->createBook();
        for ($i = 0; $i < 8; $i++) {
            $this->drupalGet('test-book/' . $nodes[$i]->id());
            for ($j = 0; $j < $i; $j++) {
                $this->assertSession()
                    ->linkExists($nodes[$j]->label());
            }
        }
    }

}