get( \Magento\Framework\View\LayoutInterface::class ); /** @var $block \Magento\Catalog\Block\Product\View\Additional */ $block = $layout->createBlock(\Magento\Catalog\Block\Product\View\Additional::class, 'block'); /** @var $childFirst \Magento\Framework\View\Element\Text */ $childFirst = $layout->addBlock(\Magento\Framework\View\Element\Text::class, 'child1', 'block'); $htmlFirst = 'Any html of child1'; $childFirst->setText($htmlFirst); /** @var $childSecond \Magento\Framework\View\Element\Text */ $childSecond = $layout->addBlock(\Magento\Framework\View\Element\Text::class, 'child2', 'block'); $htmlSecond = 'Any html of child2'; $childSecond->setText($htmlSecond); $list = $block->getChildHtmlList(); $this->assertIsArray($list); $this->assertCount(2, $list); $this->assertContains($htmlFirst, $list); $this->assertContains($htmlSecond, $list); } }