Sulu\Component\Contact\Model\ContactInterface::getFirstName PHP Method

    public function getFirstName();

 /**
  * Compares an order-address response with its origin entities.
  *
  * @param OrderAddressInterface $orderAddress
  * @param Address $address
  * @param ContactInterface $contact
  * @param AccountInterface $account
  */
 protected function checkOrderAddress($orderAddress, Address $address, ContactInterface $contact, AccountInterface $account = null)
 {
     // Contact
     $this->assertEquals($contact->getFirstName(), $orderAddress->firstName);
     $this->assertEquals($contact->getLastName(), $orderAddress->lastName);
     if ($contact->getTitle() !== null) {
         $this->assertEquals($contact->getTitle()->getTitle(), $orderAddress->title);
     }
     // Address
     $this->assertEqualsIfExists($address->getStreet(), $orderAddress, 'street');
     $this->assertEqualsIfExists($address->getAddition(), $orderAddress, 'addition');
     $this->assertEqualsIfExists($address->getNumber(), $orderAddress, 'number');
     $this->assertEqualsIfExists($address->getCity(), $orderAddress, 'city');
     $this->assertEqualsIfExists($address->getZip(), $orderAddress, 'zip');
     $this->assertEqualsIfExists($address->getCountry()->getName(), $orderAddress, 'country');
     $this->assertEqualsIfExists($address->getPostboxNumber(), $orderAddress, 'postboxNumber');
     $this->assertEqualsIfExists($address->getPostboxCity(), $orderAddress, 'postboxCity');
     $this->assertEqualsIfExists($address->getPostboxPostcode(), $orderAddress, 'postboxPostcode');
     // Account
     if ($account) {
         $this->assertEqualsIfExists($account->getName(), $orderAddress, 'accountName');
         $this->assertEqualsIfExists($account->getUid(), $orderAddress, 'uid');
     }
 }