public function testApply()
 {
     $this->_model->getState()->addFilter(\Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create('Magento\\Catalog\\Model\\Layer\\Filter\\Item', array('data' => array('filter' => \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create('Magento\\Catalog\\Model\\Layer\\Filter\\Category', array('layer' => $this->_model)), 'value' => 'expected-value-string'))))->addFilter(\Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create('Magento\\Catalog\\Model\\Layer\\Filter\\Item', array('data' => array('filter' => \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create('Magento\\Catalog\\Model\\Layer\\Filter\\Decimal', array('layer' => $this->_model)), 'value' => 1234))));
     $this->_model->apply();
     $this->assertEquals('STORE_1_CAT_4_CUSTGROUP_0_cat_expected-value-string_decimal_1234', $this->_model->getStateKey());
     $this->_model->apply();
     $this->assertEquals('STORE_1_CAT_4_CUSTGROUP_0_cat_expected-value-string_decimal_1234_cat_expected-value-string_decimal_1234', $this->_model->getStateKey());
 }
 /**
  * {@inheritdoc}
  */
 public function getStateKey()
 {
     $pluginInfo = $this->pluginList->getNext($this->subjectType, 'getStateKey');
     if (!$pluginInfo) {
         return parent::getStateKey();
     } else {
         return $this->___callPlugins('getStateKey', func_get_args(), $pluginInfo);
     }
 }