public function testGetBlockHtml()
 {
     // Without layout
     /** @var $blockFactory \Magento\Framework\View\Element\BlockFactory */
     $blockFactory = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->get('Magento\\Framework\\View\\Element\\BlockFactory');
     $block1 = $blockFactory->createBlock('Magento\\Framework\\View\\Element\\Text');
     $block1->setText('Block text');
     $block1->setNameInLayout('block');
     $html = $this->_block->getBlockHtml('block');
     $this->assertInternalType('string', $html);
     $this->assertEmpty($html);
     // With layout
     $expected = 'Block2';
     $block2 = $this->_createBlockWithLayout('block2', 'block2', 'Magento\\Framework\\View\\Element\\Text');
     $block3 = $this->_createBlockWithLayout('block3', 'block3');
     $block2->setText($expected);
     $html = $block3->getBlockHtml('block2');
     $this->assertInternalType('string', $html);
     $this->assertEquals($expected, $html);
 }