public function testHelper() { // Without layout $this->assertInstanceOf('Mage_Core_Helper_Data', $this->_block->helper('Mage_Core_Helper_Data')); // With layout $this->_block->setLayout(new Mage_Core_Model_Layout()); $helper = $this->_block->helper('Mage_Core_Helper_Data'); try { $this->assertInstanceOf('Mage_Core_Helper_Data', $helper); $this->assertInstanceOf('Mage_Core_Model_Layout', $helper->getLayout()); /* Helper is a 'singleton', so assigned layout may affect further helper usage */ $helper->setLayout(null); } catch (Exception $e) { $helper->setLayout(null); throw $e; } }