class BookUninstallTest

class BookUninstallTest extends KernelTestBase {
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'system',
    'user',
    'field',
    'filter',
    'text',
    'node',
    'book',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->installEntitySchema('user');
    $this->installEntitySchema('node');
    $this->installSchema('book', [
      'book',
    ]);
    $this->installSchema('node', [
      'node_access',
    ]);
    $this->installConfig([
      'node',
      'book',
      'field',
    ]);
    // For uninstall to work.
    $this->installSchema('user', [
      'users_data',
    ]);
  }
  
  /**
   * Tests the book_system_info_alter() method.
   */
  public function testBookUninstall() {
    // No nodes exist.
    $validation_reasons = \Drupal::service('module_installer')->validateUninstall([
      'book',
    ]);
    $this->assertEquals([], $validation_reasons, 'The book module is not required.');
    $content_type = NodeType::create([
      'type' => $this->randomMachineName(),
      'name' => $this->randomString(),
    ]);
    $content_type->save();
    $book_config = $this->config('book.settings');
    $allowed_types = $book_config->get('allowed_types');
    $allowed_types[] = $content_type->id();
    $book_config->set('allowed_types', $allowed_types)
      ->save();
    $node = Node::create([
      'title' => $this->randomString(),
      'type' => $content_type->id(),
    ]);
    $node->book['bid'] = 'new';
    $node->save();
    // One node in a book but not of type book.
    $validation_reasons = \Drupal::service('module_installer')->validateUninstall([
      'book',
    ]);
    $this->assertEquals([
      'To uninstall Book, delete all content that is part of a book',
    ], $validation_reasons['book']);
    $book_node = Node::create([
      'title' => $this->randomString(),
      'type' => 'book',
    ]);
    $book_node->book['bid'] = FALSE;
    $book_node->save();
    // Two nodes, one in a book but not of type book and one book node (which is
    // not in a book).
    $validation_reasons = \Drupal::service('module_installer')->validateUninstall([
      'book',
    ]);
    $this->assertEquals([
      'To uninstall Book, delete all content that is part of a book',
    ], $validation_reasons['book']);
    $node->delete();
    // One node of type book but not actually part of a book.
    $validation_reasons = \Drupal::service('module_installer')->validateUninstall([
      'book',
    ]);
    $this->assertEquals([
      'To uninstall Book, delete all content that has the Book content type',
    ], $validation_reasons['book']);
    $book_node->delete();
    // No nodes exist therefore the book module is not required.
    $module_data = \Drupal::service('extension.list.module')->getList();
    $this->assertFalse(isset($module_data['book']->info['required']), 'The book module is not required.');
    $node = Node::create([
      'title' => $this->randomString(),
      'type' => $content_type->id(),
    ]);
    $node->save();
    // One node exists but is not part of a book therefore the book module is
    // not required.
    $validation_reasons = \Drupal::service('module_installer')->validateUninstall([
      'book',
    ]);
    $this->assertEquals([], $validation_reasons, 'The book module is not required.');
    // Uninstall the Book module and check the node type is deleted.
    \Drupal::service('module_installer')->uninstall([
      'book',
    ]);
    $this->assertNull(NodeType::load('book'), "The book node type does not exist.");
  }

}