Omnipay\Common\CreditCard::validate PHP Method

    public function validate()
    {
        foreach (array('number', 'expiryMonth', 'expiryYear') as $key) {
            if (!$this->getParameter($key)) {
                throw new InvalidCreditCardException("The {$key} parameter is required");
            }
        }
        if ($this->getExpiryDate('Ym') < gmdate('Ym')) {
            throw new InvalidCreditCardException('Card has expired');
        }
        if (!Helper::validateLuhn($this->getNumber())) {
            throw new InvalidCreditCardException('Card number is invalid');
        }
        if (!is_null($this->getNumber()) && !preg_match('/^\\d{12,19}$/i', $this->getNumber())) {
            throw new InvalidCreditCardException('Card number should have 12 to 19 digits');
        }
    }

 /**
  * @expectedException Omnipay\Common\Exception\InvalidCreditCardException
  * @expectedExceptionMessage Card number should have 12 to 19 digits
  */
 public function testInvalidShortCard()
 {
     $this->card->setNumber('4440');
     $this->card->validate();
 }