Sylius\Behat\Page\Shop\Cart\SummaryPageInterface::getItemUnitPrice PHP Method

    public function getItemUnitPrice($productName);

 /**
  * @Then /^(its|theirs) price should be decreased by ("[^"]+")$/
  * @Then /^(product "[^"]+") price should be decreased by ("[^"]+")$/
  */
 public function itsPriceShouldBeDecreasedBy(ProductInterface $product, $amount)
 {
     $this->summaryPage->open();
     $quantity = $this->summaryPage->getQuantity($product->getName());
     $unitPrice = $this->summaryPage->getItemUnitPrice($product->getName());
     $regularUnitPrice = $this->summaryPage->getItemUnitRegularPrice($product->getName());
     Assert::same($quantity * $unitPrice, $quantity * $regularUnitPrice - $amount, 'Price after discount should be %s, but it is %2$s.');
 }