class MessagesTest

class MessagesTest extends UnitTestCase {
    
    /**
     * The view executable object.
     *
     * @var \Drupal\views\ViewExecutable
     */
    protected $view;
    
    /**
     * The message handler.
     *
     * @var \Drupal\views\Plugin\views\area\Messages
     */
    protected $messagesHandler;
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        $this->messagesHandler = new Messages([], 'result', []);
    }
    
    /**
     * Tests the render method.
     *
     * @covers ::defineOptions
     * @covers ::render
     */
    public function testRender() : void {
        // The handler is configured to show with empty views by default, so should
        // appear.
        $this->assertSame([
            '#type' => 'status_messages',
        ], $this->messagesHandler
            ->render());
        // Turn empty off, and make sure it isn't rendered.
        $this->messagesHandler->options['empty'] = FALSE;
        // $empty parameter passed to render will still be FALSE, so should still
        // appear.
        $this->assertSame([
            '#type' => 'status_messages',
        ], $this->messagesHandler
            ->render());
        // Should now be empty as both the empty option and parameter are empty.
        $this->assertSame([], $this->messagesHandler
            ->render(TRUE));
    }

}