public function testSetNationalIdentificationNumber()
 {
     $card = new CreditCard();
     $this->assertNull($card->getNationalIdentificationNumber());
     $this->assertNull($card->getSocialSecurityNumber());
     $value = uniqid();
     $this->assertSame($card, $card->setNationalIdentificationNumber($value));
     $this->assertSame($value, $card->getNationalIdentificationNumber());
     $this->assertSame($value, $card->getSocialSecurityNumber());
     $this->assertSame($card, $card->setNationalIdentificationNumber(null));
     $this->assertNull($card->getNationalIdentificationNumber());
     $this->assertNull($card->getSocialSecurityNumber());
 }